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@@ -0,0 +1,1818 @@
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+/*
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+ *
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+ * Copyright 2016, Google Inc.
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+ * All rights reserved.
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+ *
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+ * Redistribution and use in source and binary forms, with or without
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+ * modification, are permitted provided that the following conditions are
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+ * met:
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+ *
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+ * * Redistributions of source code must retain the above copyright
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+ * notice, this list of conditions and the following disclaimer.
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+ * * Redistributions in binary form must reproduce the above
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+ * copyright notice, this list of conditions and the following disclaimer
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+ * in the documentation and/or other materials provided with the
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+ * distribution.
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+ * * Neither the name of Google Inc. nor the names of its
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+ * contributors may be used to endorse or promote products derived from
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+ * this software without specific prior written permission.
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+ *
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+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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+ *
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+ */
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+
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+#include <grpc/grpc_posix.h>
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+#include <grpc/support/port_platform.h>
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+
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+/* This polling engine is only relevant on linux kernels supporting epoll() */
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+#ifdef GPR_LINUX_EPOLL
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+
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+#include "src/core/lib/iomgr/ev_epoll_linux.h"
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+
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+#include <assert.h>
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+#include <errno.h>
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+#include <poll.h>
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+#include <signal.h>
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+#include <string.h>
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+#include <sys/epoll.h>
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+#include <sys/socket.h>
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+#include <unistd.h>
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+
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+#include <grpc/support/alloc.h>
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+#include <grpc/support/log.h>
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+#include <grpc/support/string_util.h>
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+#include <grpc/support/tls.h>
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+#include <grpc/support/useful.h>
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+
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+#include "src/core/lib/iomgr/ev_posix.h"
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+#include "src/core/lib/iomgr/iomgr_internal.h"
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+#include "src/core/lib/iomgr/wakeup_fd_posix.h"
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+#include "src/core/lib/profiling/timers.h"
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+#include "src/core/lib/support/block_annotate.h"
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+
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+static int grpc_wakeup_signal = -1;
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+static bool is_grpc_wakeup_signal_initialized = false;
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+
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+/* Implements the function defined in grpc_posix.h. This function might be
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+ * called before even calling grpc_init() to set either a different signal to
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+ * use. If signum == -1, then the use of signals is disabled */
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+void grpc_use_signal(int signum) {
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+ grpc_wakeup_signal = signum;
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+ is_grpc_wakeup_signal_initialized = true;
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+
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+ if (grpc_wakeup_signal < 0) {
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+ gpr_log(GPR_INFO,
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+ "Use of signals is disabled. Epoll engine will not be used");
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+ } else {
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+ gpr_log(GPR_INFO, "epoll engine will be using signal: %d",
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+ grpc_wakeup_signal);
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+ }
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+}
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+
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+struct polling_island;
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+
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+/*******************************************************************************
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+ * Fd Declarations
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+ */
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+struct grpc_fd {
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+ int fd;
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+ /* refst format:
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+ bit 0 : 1=Active / 0=Orphaned
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+ bits 1-n : refcount
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+ Ref/Unref by two to avoid altering the orphaned bit */
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+ gpr_atm refst;
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+
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+ gpr_mu mu;
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+
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+ /* Indicates that the fd is shutdown and that any pending read/write closures
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+ should fail */
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+ bool shutdown;
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+
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+ /* The fd is either closed or we relinquished control of it. In either cases,
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+ this indicates that the 'fd' on this structure is no longer valid */
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+ bool orphaned;
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+
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+ /* TODO: sreek - Move this to a lockfree implementation */
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+ grpc_closure *read_closure;
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+ grpc_closure *write_closure;
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+
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+ /* The polling island to which this fd belongs to and the mutex protecting the
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+ the field */
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+ gpr_mu pi_mu;
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+ struct polling_island *polling_island;
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+
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+ struct grpc_fd *freelist_next;
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+ grpc_closure *on_done_closure;
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+
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+ /* The pollset that last noticed that the fd is readable */
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+ grpc_pollset *read_notifier_pollset;
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+
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+ grpc_iomgr_object iomgr_object;
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+};
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+
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+/* Reference counting for fds */
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+// #define GRPC_FD_REF_COUNT_DEBUG
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+#ifdef GRPC_FD_REF_COUNT_DEBUG
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+static void fd_ref(grpc_fd *fd, const char *reason, const char *file, int line);
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+static void fd_unref(grpc_fd *fd, const char *reason, const char *file,
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+ int line);
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+#define GRPC_FD_REF(fd, reason) fd_ref(fd, reason, __FILE__, __LINE__)
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+#define GRPC_FD_UNREF(fd, reason) fd_unref(fd, reason, __FILE__, __LINE__)
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+#else
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+static void fd_ref(grpc_fd *fd);
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+static void fd_unref(grpc_fd *fd);
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+#define GRPC_FD_REF(fd, reason) fd_ref(fd)
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+#define GRPC_FD_UNREF(fd, reason) fd_unref(fd)
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+#endif
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+
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+static void fd_global_init(void);
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+static void fd_global_shutdown(void);
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+
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+#define CLOSURE_NOT_READY ((grpc_closure *)0)
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+#define CLOSURE_READY ((grpc_closure *)1)
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+
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+/*******************************************************************************
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+ * Polling island Declarations
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+ */
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+
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+// #define GRPC_PI_REF_COUNT_DEBUG
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+#ifdef GRPC_PI_REF_COUNT_DEBUG
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+
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+#define PI_ADD_REF(p, r) pi_add_ref_dbg((p), (r), __FILE__, __LINE__)
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+#define PI_UNREF(p, r) pi_unref_dbg((p), (r), __FILE__, __LINE__)
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+
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+#else /* defined(GRPC_PI_REF_COUNT_DEBUG) */
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+
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+#define PI_ADD_REF(p, r) pi_add_ref((p))
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+#define PI_UNREF(p, r) pi_unref((p))
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+
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+#endif /* !defined(GPRC_PI_REF_COUNT_DEBUG) */
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+
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+typedef struct polling_island {
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+ gpr_mu mu;
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+ /* Ref count. Use PI_ADD_REF() and PI_UNREF() macros to increment/decrement
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+ the refcount.
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+ Once the ref count becomes zero, this structure is destroyed which means
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+ we should ensure that there is never a scenario where a PI_ADD_REF() is
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+ racing with a PI_UNREF() that just made the ref_count zero. */
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+ gpr_refcount ref_count;
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+
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+ /* Pointer to the polling_island this merged into.
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+ * merged_to value is only set once in polling_island's lifetime (and that too
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+ * only if the island is merged with another island). Because of this, we can
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+ * use gpr_atm type here so that we can do atomic access on this and reduce
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+ * lock contention on 'mu' mutex.
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+ *
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+ * Note that if this field is not NULL (i.e not 0), all the remaining fields
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+ * (except mu and ref_count) are invalid and must be ignored. */
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+ gpr_atm merged_to;
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+
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+ /* The fd of the underlying epoll set */
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+ int epoll_fd;
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+
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+ /* The file descriptors in the epoll set */
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+ size_t fd_cnt;
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+ size_t fd_capacity;
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+ grpc_fd **fds;
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+
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+ /* Polling islands that are no longer needed are kept in a freelist so that
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+ they can be reused. This field points to the next polling island in the
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+ free list */
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+ struct polling_island *next_free;
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+} polling_island;
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+
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+/*******************************************************************************
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+ * Pollset Declarations
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+ */
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+struct grpc_pollset_worker {
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+ pthread_t pt_id; /* Thread id of this worker */
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+ struct grpc_pollset_worker *next;
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+ struct grpc_pollset_worker *prev;
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+};
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+
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+struct grpc_pollset {
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+ gpr_mu mu;
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+ grpc_pollset_worker root_worker;
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+ bool kicked_without_pollers;
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+
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+ bool shutting_down; /* Is the pollset shutting down ? */
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+ bool finish_shutdown_called; /* Is the 'finish_shutdown_locked()' called ? */
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+ grpc_closure *shutdown_done; /* Called after after shutdown is complete */
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+
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+ /* The polling island to which this pollset belongs to */
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+ struct polling_island *polling_island;
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+};
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+
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+/*******************************************************************************
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+ * Pollset-set Declarations
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+ */
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+/* TODO: sreek - Change the pollset_set implementation such that a pollset_set
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+ * directly points to a polling_island (and adding an fd/pollset/pollset_set to
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+ * the current pollset_set would result in polling island merges. This would
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+ * remove the need to maintain fd_count here. This will also significantly
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+ * simplify the grpc_fd structure since we would no longer need to explicitly
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+ * maintain the orphaned state */
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+struct grpc_pollset_set {
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+ gpr_mu mu;
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+
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+ size_t pollset_count;
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+ size_t pollset_capacity;
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+ grpc_pollset **pollsets;
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+
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+ size_t pollset_set_count;
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+ size_t pollset_set_capacity;
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+ struct grpc_pollset_set **pollset_sets;
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+
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+ size_t fd_count;
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+ size_t fd_capacity;
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+ grpc_fd **fds;
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+};
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+
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+/*******************************************************************************
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+ * Common helpers
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+ */
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+
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+static void append_error(grpc_error **composite, grpc_error *error,
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+ const char *desc) {
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+ if (error == GRPC_ERROR_NONE) return;
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+ if (*composite == GRPC_ERROR_NONE) {
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+ *composite = GRPC_ERROR_CREATE(desc);
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+ }
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+ *composite = grpc_error_add_child(*composite, error);
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+}
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+
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+/*******************************************************************************
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+ * Polling island Definitions
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+ */
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+
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+/* The wakeup fd that is used to wake up all threads in a Polling island. This
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+ is useful in the polling island merge operation where we need to wakeup all
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+ the threads currently polling the smaller polling island (so that they can
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+ start polling the new/merged polling island)
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+
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+ NOTE: This fd is initialized to be readable and MUST NOT be consumed i.e the
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+ threads that woke up MUST NOT call grpc_wakeup_fd_consume_wakeup() */
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+static grpc_wakeup_fd polling_island_wakeup_fd;
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+
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+/* Polling island freelist */
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+static gpr_mu g_pi_freelist_mu;
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+static polling_island *g_pi_freelist = NULL;
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+
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+static void polling_island_delete(); /* Forward declaration */
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+
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+#ifdef GRPC_TSAN
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+/* Currently TSAN may incorrectly flag data races between epoll_ctl and
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+ epoll_wait for any grpc_fd structs that are added to the epoll set via
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+ epoll_ctl and are returned (within a very short window) via epoll_wait().
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+
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+ To work-around this race, we establish a happens-before relation between
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+ the code just-before epoll_ctl() and the code after epoll_wait() by using
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+ this atomic */
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+gpr_atm g_epoll_sync;
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+#endif /* defined(GRPC_TSAN) */
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+
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+#ifdef GRPC_PI_REF_COUNT_DEBUG
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+void pi_add_ref(polling_island *pi);
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+void pi_unref(polling_island *pi);
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+
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+void pi_add_ref_dbg(polling_island *pi, char *reason, char *file, int line) {
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+ long old_cnt = gpr_atm_acq_load(&(pi->ref_count.count));
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+ pi_add_ref(pi);
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+ gpr_log(GPR_DEBUG, "Add ref pi: %p, old: %ld -> new:%ld (%s) - (%s, %d)",
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+ (void *)pi, old_cnt, old_cnt + 1, reason, file, line);
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+}
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+
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+void pi_unref_dbg(polling_island *pi, char *reason, char *file, int line) {
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+ long old_cnt = gpr_atm_acq_load(&(pi->ref_count.count));
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+ pi_unref(pi);
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+ gpr_log(GPR_DEBUG, "Unref pi: %p, old:%ld -> new:%ld (%s) - (%s, %d)",
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+ (void *)pi, old_cnt, (old_cnt - 1), reason, file, line);
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+}
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+#endif
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+
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+void pi_add_ref(polling_island *pi) { gpr_ref(&pi->ref_count); }
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+
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+void pi_unref(polling_island *pi) {
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+ /* If ref count went to zero, delete the polling island.
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+ Note that this deletion not be done under a lock. Once the ref count goes
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+ to zero, we are guaranteed that no one else holds a reference to the
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+ polling island (and that there is no racing pi_add_ref() call either).
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+
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+ Also, if we are deleting the polling island and the merged_to field is
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+ non-empty, we should remove a ref to the merged_to polling island
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+ */
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+ if (gpr_unref(&pi->ref_count)) {
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+ polling_island *next = (polling_island *)gpr_atm_acq_load(&pi->merged_to);
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+ polling_island_delete(pi);
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+ if (next != NULL) {
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+ PI_UNREF(next, "pi_delete"); /* Recursive call */
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+ }
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+ }
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+}
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+
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+/* The caller is expected to hold pi->mu lock before calling this function */
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+static void polling_island_add_fds_locked(polling_island *pi, grpc_fd **fds,
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+ size_t fd_count, bool add_fd_refs,
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+ grpc_error **error) {
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+ int err;
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+ size_t i;
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+ struct epoll_event ev;
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+ char *err_msg;
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+ const char *err_desc = "polling_island_add_fds";
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+
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+#ifdef GRPC_TSAN
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+ /* See the definition of g_epoll_sync for more context */
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+ gpr_atm_rel_store(&g_epoll_sync, (gpr_atm)0);
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+#endif /* defined(GRPC_TSAN) */
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+
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+ for (i = 0; i < fd_count; i++) {
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+ ev.events = (uint32_t)(EPOLLIN | EPOLLOUT | EPOLLET);
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+ ev.data.ptr = fds[i];
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+ err = epoll_ctl(pi->epoll_fd, EPOLL_CTL_ADD, fds[i]->fd, &ev);
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+
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+ if (err < 0) {
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+ if (errno != EEXIST) {
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+ gpr_asprintf(
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+ &err_msg,
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+ "epoll_ctl (epoll_fd: %d) add fd: %d failed with error: %d (%s)",
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+ pi->epoll_fd, fds[i]->fd, errno, strerror(errno));
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+ append_error(error, GRPC_OS_ERROR(errno, err_msg), err_desc);
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+ gpr_free(err_msg);
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+ }
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+
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+ continue;
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+ }
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+
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+ if (pi->fd_cnt == pi->fd_capacity) {
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+ pi->fd_capacity = GPR_MAX(pi->fd_capacity + 8, pi->fd_cnt * 3 / 2);
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+ pi->fds = gpr_realloc(pi->fds, sizeof(grpc_fd *) * pi->fd_capacity);
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+ }
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+
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+ pi->fds[pi->fd_cnt++] = fds[i];
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+ if (add_fd_refs) {
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+ GRPC_FD_REF(fds[i], "polling_island");
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+ }
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+ }
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+}
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+
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+/* The caller is expected to hold pi->mu before calling this */
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+static void polling_island_add_wakeup_fd_locked(polling_island *pi,
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+ grpc_wakeup_fd *wakeup_fd,
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+ grpc_error **error) {
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+ struct epoll_event ev;
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+ int err;
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+ char *err_msg;
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|
|
+ const char *err_desc = "polling_island_add_wakeup_fd";
|
|
|
+
|
|
|
+ ev.events = (uint32_t)(EPOLLIN | EPOLLET);
|
|
|
+ ev.data.ptr = wakeup_fd;
|
|
|
+ err = epoll_ctl(pi->epoll_fd, EPOLL_CTL_ADD,
|
|
|
+ GRPC_WAKEUP_FD_GET_READ_FD(wakeup_fd), &ev);
|
|
|
+ if (err < 0 && errno != EEXIST) {
|
|
|
+ gpr_asprintf(&err_msg,
|
|
|
+ "epoll_ctl (epoll_fd: %d) add wakeup fd: %d failed with "
|
|
|
+ "error: %d (%s)",
|
|
|
+ pi->epoll_fd,
|
|
|
+ GRPC_WAKEUP_FD_GET_READ_FD(&grpc_global_wakeup_fd), errno,
|
|
|
+ strerror(errno));
|
|
|
+ append_error(error, GRPC_OS_ERROR(errno, err_msg), err_desc);
|
|
|
+ gpr_free(err_msg);
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+/* The caller is expected to hold pi->mu lock before calling this function */
|
|
|
+static void polling_island_remove_all_fds_locked(polling_island *pi,
|
|
|
+ bool remove_fd_refs,
|
|
|
+ grpc_error **error) {
|
|
|
+ int err;
|
|
|
+ size_t i;
|
|
|
+ char *err_msg;
|
|
|
+ const char *err_desc = "polling_island_remove_fds";
|
|
|
+
|
|
|
+ for (i = 0; i < pi->fd_cnt; i++) {
|
|
|
+ err = epoll_ctl(pi->epoll_fd, EPOLL_CTL_DEL, pi->fds[i]->fd, NULL);
|
|
|
+ if (err < 0 && errno != ENOENT) {
|
|
|
+ gpr_asprintf(&err_msg,
|
|
|
+ "epoll_ctl (epoll_fd: %d) delete fds[%zu]: %d failed with "
|
|
|
+ "error: %d (%s)",
|
|
|
+ pi->epoll_fd, i, pi->fds[i]->fd, errno, strerror(errno));
|
|
|
+ append_error(error, GRPC_OS_ERROR(errno, err_msg), err_desc);
|
|
|
+ gpr_free(err_msg);
|
|
|
+ }
|
|
|
+
|
|
|
+ if (remove_fd_refs) {
|
|
|
+ GRPC_FD_UNREF(pi->fds[i], "polling_island");
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ pi->fd_cnt = 0;
|
|
|
+}
|
|
|
+
|
|
|
+/* The caller is expected to hold pi->mu lock before calling this function */
|
|
|
+static void polling_island_remove_fd_locked(polling_island *pi, grpc_fd *fd,
|
|
|
+ bool is_fd_closed,
|
|
|
+ grpc_error **error) {
|
|
|
+ int err;
|
|
|
+ size_t i;
|
|
|
+ char *err_msg;
|
|
|
+ const char *err_desc = "polling_island_remove_fd";
|
|
|
+
|
|
|
+ /* If fd is already closed, then it would have been automatically been removed
|
|
|
+ from the epoll set */
|
|
|
+ if (!is_fd_closed) {
|
|
|
+ err = epoll_ctl(pi->epoll_fd, EPOLL_CTL_DEL, fd->fd, NULL);
|
|
|
+ if (err < 0 && errno != ENOENT) {
|
|
|
+ gpr_asprintf(
|
|
|
+ &err_msg,
|
|
|
+ "epoll_ctl (epoll_fd: %d) del fd: %d failed with error: %d (%s)",
|
|
|
+ pi->epoll_fd, fd->fd, errno, strerror(errno));
|
|
|
+ append_error(error, GRPC_OS_ERROR(errno, err_msg), err_desc);
|
|
|
+ gpr_free(err_msg);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ for (i = 0; i < pi->fd_cnt; i++) {
|
|
|
+ if (pi->fds[i] == fd) {
|
|
|
+ pi->fds[i] = pi->fds[--pi->fd_cnt];
|
|
|
+ GRPC_FD_UNREF(fd, "polling_island");
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+/* Might return NULL in case of an error */
|
|
|
+static polling_island *polling_island_create(grpc_fd *initial_fd,
|
|
|
+ grpc_error **error) {
|
|
|
+ polling_island *pi = NULL;
|
|
|
+ char *err_msg;
|
|
|
+ const char *err_desc = "polling_island_create";
|
|
|
+
|
|
|
+ /* Try to get one from the polling island freelist */
|
|
|
+ gpr_mu_lock(&g_pi_freelist_mu);
|
|
|
+ if (g_pi_freelist != NULL) {
|
|
|
+ pi = g_pi_freelist;
|
|
|
+ g_pi_freelist = g_pi_freelist->next_free;
|
|
|
+ pi->next_free = NULL;
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&g_pi_freelist_mu);
|
|
|
+
|
|
|
+ /* Create new polling island if we could not get one from the free list */
|
|
|
+ if (pi == NULL) {
|
|
|
+ pi = gpr_malloc(sizeof(*pi));
|
|
|
+ gpr_mu_init(&pi->mu);
|
|
|
+ pi->fd_cnt = 0;
|
|
|
+ pi->fd_capacity = 0;
|
|
|
+ pi->fds = NULL;
|
|
|
+ }
|
|
|
+
|
|
|
+ gpr_ref_init(&pi->ref_count, 0);
|
|
|
+ gpr_atm_rel_store(&pi->merged_to, (gpr_atm)NULL);
|
|
|
+
|
|
|
+ pi->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
|
|
|
+
|
|
|
+ if (pi->epoll_fd < 0) {
|
|
|
+ gpr_asprintf(&err_msg, "epoll_create1 failed with error %d (%s)", errno,
|
|
|
+ strerror(errno));
|
|
|
+ append_error(error, GRPC_OS_ERROR(errno, err_msg), err_desc);
|
|
|
+ gpr_free(err_msg);
|
|
|
+ } else {
|
|
|
+ polling_island_add_wakeup_fd_locked(pi, &grpc_global_wakeup_fd, error);
|
|
|
+ pi->next_free = NULL;
|
|
|
+
|
|
|
+ if (initial_fd != NULL) {
|
|
|
+ /* Lock the polling island here just in case we got this structure from
|
|
|
+ the freelist and the polling island lock was not released yet (by the
|
|
|
+ code that adds the polling island to the freelist) */
|
|
|
+ gpr_mu_lock(&pi->mu);
|
|
|
+ polling_island_add_fds_locked(pi, &initial_fd, 1, true, error);
|
|
|
+ gpr_mu_unlock(&pi->mu);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ return pi;
|
|
|
+}
|
|
|
+
|
|
|
+static void polling_island_delete(polling_island *pi) {
|
|
|
+ GPR_ASSERT(pi->fd_cnt == 0);
|
|
|
+
|
|
|
+ gpr_atm_rel_store(&pi->merged_to, (gpr_atm)NULL);
|
|
|
+
|
|
|
+ close(pi->epoll_fd);
|
|
|
+ pi->epoll_fd = -1;
|
|
|
+
|
|
|
+ gpr_mu_lock(&g_pi_freelist_mu);
|
|
|
+ pi->next_free = g_pi_freelist;
|
|
|
+ g_pi_freelist = pi;
|
|
|
+ gpr_mu_unlock(&g_pi_freelist_mu);
|
|
|
+}
|
|
|
+
|
|
|
+/* Attempts to gets the last polling island in the linked list (liked by the
|
|
|
+ * 'merged_to' field). Since this does not lock the polling island, there are no
|
|
|
+ * guarantees that the island returned is the last island */
|
|
|
+static polling_island *polling_island_maybe_get_latest(polling_island *pi) {
|
|
|
+ polling_island *next = (polling_island *)gpr_atm_acq_load(&pi->merged_to);
|
|
|
+ while (next != NULL) {
|
|
|
+ pi = next;
|
|
|
+ next = (polling_island *)gpr_atm_acq_load(&pi->merged_to);
|
|
|
+ }
|
|
|
+
|
|
|
+ return pi;
|
|
|
+}
|
|
|
+
|
|
|
+/* Gets the lock on the *latest* polling island i.e the last polling island in
|
|
|
+ the linked list (linked by the 'merged_to' field). Call gpr_mu_unlock on the
|
|
|
+ returned polling island's mu.
|
|
|
+ Usage: To lock/unlock polling island "pi", do the following:
|
|
|
+ polling_island *pi_latest = polling_island_lock(pi);
|
|
|
+ ...
|
|
|
+ ... critical section ..
|
|
|
+ ...
|
|
|
+ gpr_mu_unlock(&pi_latest->mu); // NOTE: use pi_latest->mu. NOT pi->mu */
|
|
|
+static polling_island *polling_island_lock(polling_island *pi) {
|
|
|
+ polling_island *next = NULL;
|
|
|
+
|
|
|
+ while (true) {
|
|
|
+ next = (polling_island *)gpr_atm_acq_load(&pi->merged_to);
|
|
|
+ if (next == NULL) {
|
|
|
+ /* Looks like 'pi' is the last node in the linked list but unless we check
|
|
|
+ this by holding the pi->mu lock, we cannot be sure (i.e without the
|
|
|
+ pi->mu lock, we don't prevent island merges).
|
|
|
+ To be absolutely sure, check once more by holding the pi->mu lock */
|
|
|
+ gpr_mu_lock(&pi->mu);
|
|
|
+ next = (polling_island *)gpr_atm_acq_load(&pi->merged_to);
|
|
|
+ if (next == NULL) {
|
|
|
+ /* pi is infact the last node and we have the pi->mu lock. we're done */
|
|
|
+ break;
|
|
|
+ }
|
|
|
+
|
|
|
+ /* pi->merged_to is not NULL i.e pi isn't the last node anymore. pi->mu
|
|
|
+ * isn't the lock we are interested in. Continue traversing the list */
|
|
|
+ gpr_mu_unlock(&pi->mu);
|
|
|
+ }
|
|
|
+
|
|
|
+ pi = next;
|
|
|
+ }
|
|
|
+
|
|
|
+ return pi;
|
|
|
+}
|
|
|
+
|
|
|
+/* Gets the lock on the *latest* polling islands in the linked lists pointed by
|
|
|
+ *p and *q (and also updates *p and *q to point to the latest polling islands)
|
|
|
+
|
|
|
+ This function is needed because calling the following block of code to obtain
|
|
|
+ locks on polling islands (*p and *q) is prone to deadlocks.
|
|
|
+ {
|
|
|
+ polling_island_lock(*p, true);
|
|
|
+ polling_island_lock(*q, true);
|
|
|
+ }
|
|
|
+
|
|
|
+ Usage/example:
|
|
|
+ polling_island *p1;
|
|
|
+ polling_island *p2;
|
|
|
+ ..
|
|
|
+ polling_island_lock_pair(&p1, &p2);
|
|
|
+ ..
|
|
|
+ .. Critical section with both p1 and p2 locked
|
|
|
+ ..
|
|
|
+ // Release locks: Always call polling_island_unlock_pair() to release locks
|
|
|
+ polling_island_unlock_pair(p1, p2);
|
|
|
+*/
|
|
|
+static void polling_island_lock_pair(polling_island **p, polling_island **q) {
|
|
|
+ polling_island *pi_1 = *p;
|
|
|
+ polling_island *pi_2 = *q;
|
|
|
+ polling_island *next_1 = NULL;
|
|
|
+ polling_island *next_2 = NULL;
|
|
|
+
|
|
|
+ /* The algorithm is simple:
|
|
|
+ - Go to the last polling islands in the linked lists *pi_1 and *pi_2 (and
|
|
|
+ keep updating pi_1 and pi_2)
|
|
|
+ - Then obtain locks on the islands by following a lock order rule of
|
|
|
+ locking polling_island with lower address first
|
|
|
+ Special case: Before obtaining the locks, check if pi_1 and pi_2 are
|
|
|
+ pointing to the same island. If that is the case, we can just call
|
|
|
+ polling_island_lock()
|
|
|
+ - After obtaining both the locks, double check that the polling islands
|
|
|
+ are still the last polling islands in their respective linked lists
|
|
|
+ (this is because there might have been polling island merges before
|
|
|
+ we got the lock)
|
|
|
+ - If the polling islands are the last islands, we are done. If not,
|
|
|
+ release the locks and continue the process from the first step */
|
|
|
+ while (true) {
|
|
|
+ next_1 = (polling_island *)gpr_atm_acq_load(&pi_1->merged_to);
|
|
|
+ while (next_1 != NULL) {
|
|
|
+ pi_1 = next_1;
|
|
|
+ next_1 = (polling_island *)gpr_atm_acq_load(&pi_1->merged_to);
|
|
|
+ }
|
|
|
+
|
|
|
+ next_2 = (polling_island *)gpr_atm_acq_load(&pi_2->merged_to);
|
|
|
+ while (next_2 != NULL) {
|
|
|
+ pi_2 = next_2;
|
|
|
+ next_2 = (polling_island *)gpr_atm_acq_load(&pi_2->merged_to);
|
|
|
+ }
|
|
|
+
|
|
|
+ if (pi_1 == pi_2) {
|
|
|
+ pi_1 = pi_2 = polling_island_lock(pi_1);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (pi_1 < pi_2) {
|
|
|
+ gpr_mu_lock(&pi_1->mu);
|
|
|
+ gpr_mu_lock(&pi_2->mu);
|
|
|
+ } else {
|
|
|
+ gpr_mu_lock(&pi_2->mu);
|
|
|
+ gpr_mu_lock(&pi_1->mu);
|
|
|
+ }
|
|
|
+
|
|
|
+ next_1 = (polling_island *)gpr_atm_acq_load(&pi_1->merged_to);
|
|
|
+ next_2 = (polling_island *)gpr_atm_acq_load(&pi_2->merged_to);
|
|
|
+ if (next_1 == NULL && next_2 == NULL) {
|
|
|
+ break;
|
|
|
+ }
|
|
|
+
|
|
|
+ gpr_mu_unlock(&pi_1->mu);
|
|
|
+ gpr_mu_unlock(&pi_2->mu);
|
|
|
+ }
|
|
|
+
|
|
|
+ *p = pi_1;
|
|
|
+ *q = pi_2;
|
|
|
+}
|
|
|
+
|
|
|
+static void polling_island_unlock_pair(polling_island *p, polling_island *q) {
|
|
|
+ if (p == q) {
|
|
|
+ gpr_mu_unlock(&p->mu);
|
|
|
+ } else {
|
|
|
+ gpr_mu_unlock(&p->mu);
|
|
|
+ gpr_mu_unlock(&q->mu);
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static polling_island *polling_island_merge(polling_island *p,
|
|
|
+ polling_island *q,
|
|
|
+ grpc_error **error) {
|
|
|
+ /* Get locks on both the polling islands */
|
|
|
+ polling_island_lock_pair(&p, &q);
|
|
|
+
|
|
|
+ if (p != q) {
|
|
|
+ /* Make sure that p points to the polling island with fewer fds than q */
|
|
|
+ if (p->fd_cnt > q->fd_cnt) {
|
|
|
+ GPR_SWAP(polling_island *, p, q);
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Merge p with q i.e move all the fds from p (The one with fewer fds) to q
|
|
|
+ Note that the refcounts on the fds being moved will not change here.
|
|
|
+ This is why the last param in the following two functions is 'false') */
|
|
|
+ polling_island_add_fds_locked(q, p->fds, p->fd_cnt, false, error);
|
|
|
+ polling_island_remove_all_fds_locked(p, false, error);
|
|
|
+
|
|
|
+ /* Wakeup all the pollers (if any) on p so that they pickup this change */
|
|
|
+ polling_island_add_wakeup_fd_locked(p, &polling_island_wakeup_fd, error);
|
|
|
+
|
|
|
+ /* Add the 'merged_to' link from p --> q */
|
|
|
+ gpr_atm_rel_store(&p->merged_to, (gpr_atm)q);
|
|
|
+ PI_ADD_REF(q, "pi_merge"); /* To account for the new incoming ref from p */
|
|
|
+ }
|
|
|
+ /* else if p == q, nothing needs to be done */
|
|
|
+
|
|
|
+ polling_island_unlock_pair(p, q);
|
|
|
+
|
|
|
+ /* Return the merged polling island (Note that no merge would have happened
|
|
|
+ if p == q which is ok) */
|
|
|
+ return q;
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_error *polling_island_global_init() {
|
|
|
+ grpc_error *error = GRPC_ERROR_NONE;
|
|
|
+
|
|
|
+ gpr_mu_init(&g_pi_freelist_mu);
|
|
|
+ g_pi_freelist = NULL;
|
|
|
+
|
|
|
+ error = grpc_wakeup_fd_init(&polling_island_wakeup_fd);
|
|
|
+ if (error == GRPC_ERROR_NONE) {
|
|
|
+ error = grpc_wakeup_fd_wakeup(&polling_island_wakeup_fd);
|
|
|
+ }
|
|
|
+
|
|
|
+ return error;
|
|
|
+}
|
|
|
+
|
|
|
+static void polling_island_global_shutdown() {
|
|
|
+ polling_island *next;
|
|
|
+ gpr_mu_lock(&g_pi_freelist_mu);
|
|
|
+ gpr_mu_unlock(&g_pi_freelist_mu);
|
|
|
+ while (g_pi_freelist != NULL) {
|
|
|
+ next = g_pi_freelist->next_free;
|
|
|
+ gpr_mu_destroy(&g_pi_freelist->mu);
|
|
|
+ gpr_free(g_pi_freelist->fds);
|
|
|
+ gpr_free(g_pi_freelist);
|
|
|
+ g_pi_freelist = next;
|
|
|
+ }
|
|
|
+ gpr_mu_destroy(&g_pi_freelist_mu);
|
|
|
+
|
|
|
+ grpc_wakeup_fd_destroy(&polling_island_wakeup_fd);
|
|
|
+}
|
|
|
+
|
|
|
+/*******************************************************************************
|
|
|
+ * Fd Definitions
|
|
|
+ */
|
|
|
+
|
|
|
+/* We need to keep a freelist not because of any concerns of malloc performance
|
|
|
+ * but instead so that implementations with multiple threads in (for example)
|
|
|
+ * epoll_wait deal with the race between pollset removal and incoming poll
|
|
|
+ * notifications.
|
|
|
+ *
|
|
|
+ * The problem is that the poller ultimately holds a reference to this
|
|
|
+ * object, so it is very difficult to know when is safe to free it, at least
|
|
|
+ * without some expensive synchronization.
|
|
|
+ *
|
|
|
+ * If we keep the object freelisted, in the worst case losing this race just
|
|
|
+ * becomes a spurious read notification on a reused fd.
|
|
|
+ */
|
|
|
+
|
|
|
+/* The alarm system needs to be able to wakeup 'some poller' sometimes
|
|
|
+ * (specifically when a new alarm needs to be triggered earlier than the next
|
|
|
+ * alarm 'epoch'). This wakeup_fd gives us something to alert on when such a
|
|
|
+ * case occurs. */
|
|
|
+
|
|
|
+/* TODO: sreek: Right now, this wakes up all pollers. In future we should make
|
|
|
+ * sure to wake up one polling thread (which can wake up other threads if
|
|
|
+ * needed) */
|
|
|
+grpc_wakeup_fd grpc_global_wakeup_fd;
|
|
|
+
|
|
|
+static grpc_fd *fd_freelist = NULL;
|
|
|
+static gpr_mu fd_freelist_mu;
|
|
|
+
|
|
|
+#ifdef GRPC_FD_REF_COUNT_DEBUG
|
|
|
+#define REF_BY(fd, n, reason) ref_by(fd, n, reason, __FILE__, __LINE__)
|
|
|
+#define UNREF_BY(fd, n, reason) unref_by(fd, n, reason, __FILE__, __LINE__)
|
|
|
+static void ref_by(grpc_fd *fd, int n, const char *reason, const char *file,
|
|
|
+ int line) {
|
|
|
+ gpr_log(GPR_DEBUG, "FD %d %p ref %d %ld -> %ld [%s; %s:%d]", fd->fd,
|
|
|
+ (void *)fd, n, gpr_atm_no_barrier_load(&fd->refst),
|
|
|
+ gpr_atm_no_barrier_load(&fd->refst) + n, reason, file, line);
|
|
|
+#else
|
|
|
+#define REF_BY(fd, n, reason) ref_by(fd, n)
|
|
|
+#define UNREF_BY(fd, n, reason) unref_by(fd, n)
|
|
|
+static void ref_by(grpc_fd *fd, int n) {
|
|
|
+#endif
|
|
|
+ GPR_ASSERT(gpr_atm_no_barrier_fetch_add(&fd->refst, n) > 0);
|
|
|
+}
|
|
|
+
|
|
|
+#ifdef GRPC_FD_REF_COUNT_DEBUG
|
|
|
+static void unref_by(grpc_fd *fd, int n, const char *reason, const char *file,
|
|
|
+ int line) {
|
|
|
+ gpr_atm old;
|
|
|
+ gpr_log(GPR_DEBUG, "FD %d %p unref %d %ld -> %ld [%s; %s:%d]", fd->fd,
|
|
|
+ (void *)fd, n, gpr_atm_no_barrier_load(&fd->refst),
|
|
|
+ gpr_atm_no_barrier_load(&fd->refst) - n, reason, file, line);
|
|
|
+#else
|
|
|
+static void unref_by(grpc_fd *fd, int n) {
|
|
|
+ gpr_atm old;
|
|
|
+#endif
|
|
|
+ old = gpr_atm_full_fetch_add(&fd->refst, -n);
|
|
|
+ if (old == n) {
|
|
|
+ /* Add the fd to the freelist */
|
|
|
+ gpr_mu_lock(&fd_freelist_mu);
|
|
|
+ fd->freelist_next = fd_freelist;
|
|
|
+ fd_freelist = fd;
|
|
|
+ grpc_iomgr_unregister_object(&fd->iomgr_object);
|
|
|
+
|
|
|
+ gpr_mu_unlock(&fd_freelist_mu);
|
|
|
+ } else {
|
|
|
+ GPR_ASSERT(old > n);
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+/* Increment refcount by two to avoid changing the orphan bit */
|
|
|
+#ifdef GRPC_FD_REF_COUNT_DEBUG
|
|
|
+static void fd_ref(grpc_fd *fd, const char *reason, const char *file,
|
|
|
+ int line) {
|
|
|
+ ref_by(fd, 2, reason, file, line);
|
|
|
+}
|
|
|
+
|
|
|
+static void fd_unref(grpc_fd *fd, const char *reason, const char *file,
|
|
|
+ int line) {
|
|
|
+ unref_by(fd, 2, reason, file, line);
|
|
|
+}
|
|
|
+#else
|
|
|
+static void fd_ref(grpc_fd *fd) { ref_by(fd, 2); }
|
|
|
+static void fd_unref(grpc_fd *fd) { unref_by(fd, 2); }
|
|
|
+#endif
|
|
|
+
|
|
|
+static void fd_global_init(void) { gpr_mu_init(&fd_freelist_mu); }
|
|
|
+
|
|
|
+static void fd_global_shutdown(void) {
|
|
|
+ gpr_mu_lock(&fd_freelist_mu);
|
|
|
+ gpr_mu_unlock(&fd_freelist_mu);
|
|
|
+ while (fd_freelist != NULL) {
|
|
|
+ grpc_fd *fd = fd_freelist;
|
|
|
+ fd_freelist = fd_freelist->freelist_next;
|
|
|
+ gpr_mu_destroy(&fd->mu);
|
|
|
+ gpr_free(fd);
|
|
|
+ }
|
|
|
+ gpr_mu_destroy(&fd_freelist_mu);
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_fd *fd_create(int fd, const char *name) {
|
|
|
+ grpc_fd *new_fd = NULL;
|
|
|
+
|
|
|
+ gpr_mu_lock(&fd_freelist_mu);
|
|
|
+ if (fd_freelist != NULL) {
|
|
|
+ new_fd = fd_freelist;
|
|
|
+ fd_freelist = fd_freelist->freelist_next;
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&fd_freelist_mu);
|
|
|
+
|
|
|
+ if (new_fd == NULL) {
|
|
|
+ new_fd = gpr_malloc(sizeof(grpc_fd));
|
|
|
+ gpr_mu_init(&new_fd->mu);
|
|
|
+ gpr_mu_init(&new_fd->pi_mu);
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Note: It is not really needed to get the new_fd->mu lock here. If this is a
|
|
|
+ newly created fd (or an fd we got from the freelist), no one else would be
|
|
|
+ holding a lock to it anyway. */
|
|
|
+ gpr_mu_lock(&new_fd->mu);
|
|
|
+
|
|
|
+ gpr_atm_rel_store(&new_fd->refst, (gpr_atm)1);
|
|
|
+ new_fd->fd = fd;
|
|
|
+ new_fd->shutdown = false;
|
|
|
+ new_fd->orphaned = false;
|
|
|
+ new_fd->read_closure = CLOSURE_NOT_READY;
|
|
|
+ new_fd->write_closure = CLOSURE_NOT_READY;
|
|
|
+ new_fd->polling_island = NULL;
|
|
|
+ new_fd->freelist_next = NULL;
|
|
|
+ new_fd->on_done_closure = NULL;
|
|
|
+ new_fd->read_notifier_pollset = NULL;
|
|
|
+
|
|
|
+ gpr_mu_unlock(&new_fd->mu);
|
|
|
+
|
|
|
+ char *fd_name;
|
|
|
+ gpr_asprintf(&fd_name, "%s fd=%d", name, fd);
|
|
|
+ grpc_iomgr_register_object(&new_fd->iomgr_object, fd_name);
|
|
|
+#ifdef GRPC_FD_REF_COUNT_DEBUG
|
|
|
+ gpr_log(GPR_DEBUG, "FD %d %p create %s", fd, (void *)new_fd, fd_name);
|
|
|
+#endif
|
|
|
+ gpr_free(fd_name);
|
|
|
+ return new_fd;
|
|
|
+}
|
|
|
+
|
|
|
+static bool fd_is_orphaned(grpc_fd *fd) {
|
|
|
+ return (gpr_atm_acq_load(&fd->refst) & 1) == 0;
|
|
|
+}
|
|
|
+
|
|
|
+static int fd_wrapped_fd(grpc_fd *fd) {
|
|
|
+ int ret_fd = -1;
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ if (!fd->orphaned) {
|
|
|
+ ret_fd = fd->fd;
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+
|
|
|
+ return ret_fd;
|
|
|
+}
|
|
|
+
|
|
|
+static void fd_orphan(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
|
|
|
+ grpc_closure *on_done, int *release_fd,
|
|
|
+ const char *reason) {
|
|
|
+ bool is_fd_closed = false;
|
|
|
+ grpc_error *error = GRPC_ERROR_NONE;
|
|
|
+
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ fd->on_done_closure = on_done;
|
|
|
+
|
|
|
+ /* If release_fd is not NULL, we should be relinquishing control of the file
|
|
|
+ descriptor fd->fd (but we still own the grpc_fd structure). */
|
|
|
+ if (release_fd != NULL) {
|
|
|
+ *release_fd = fd->fd;
|
|
|
+ } else {
|
|
|
+ close(fd->fd);
|
|
|
+ is_fd_closed = true;
|
|
|
+ }
|
|
|
+
|
|
|
+ fd->orphaned = true;
|
|
|
+
|
|
|
+ /* Remove the active status but keep referenced. We want this grpc_fd struct
|
|
|
+ to be alive (and not added to freelist) until the end of this function */
|
|
|
+ REF_BY(fd, 1, reason);
|
|
|
+
|
|
|
+ /* Remove the fd from the polling island:
|
|
|
+ - Get a lock on the latest polling island (i.e the last island in the
|
|
|
+ linked list pointed by fd->polling_island). This is the island that
|
|
|
+ would actually contain the fd
|
|
|
+ - Remove the fd from the latest polling island
|
|
|
+ - Unlock the latest polling island
|
|
|
+ - Set fd->polling_island to NULL (but remove the ref on the polling island
|
|
|
+ before doing this.) */
|
|
|
+ gpr_mu_lock(&fd->pi_mu);
|
|
|
+ if (fd->polling_island != NULL) {
|
|
|
+ polling_island *pi_latest = polling_island_lock(fd->polling_island);
|
|
|
+ polling_island_remove_fd_locked(pi_latest, fd, is_fd_closed, &error);
|
|
|
+ gpr_mu_unlock(&pi_latest->mu);
|
|
|
+
|
|
|
+ PI_UNREF(fd->polling_island, "fd_orphan");
|
|
|
+ fd->polling_island = NULL;
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&fd->pi_mu);
|
|
|
+
|
|
|
+ grpc_exec_ctx_sched(exec_ctx, fd->on_done_closure, error, NULL);
|
|
|
+
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+ UNREF_BY(fd, 2, reason); /* Drop the reference */
|
|
|
+ GRPC_LOG_IF_ERROR("fd_orphan", GRPC_ERROR_REF(error));
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_error *fd_shutdown_error(bool shutdown) {
|
|
|
+ if (!shutdown) {
|
|
|
+ return GRPC_ERROR_NONE;
|
|
|
+ } else {
|
|
|
+ return GRPC_ERROR_CREATE("FD shutdown");
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static void notify_on_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
|
|
|
+ grpc_closure **st, grpc_closure *closure) {
|
|
|
+ if (fd->shutdown) {
|
|
|
+ grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_CREATE("FD shutdown"),
|
|
|
+ NULL);
|
|
|
+ } else if (*st == CLOSURE_NOT_READY) {
|
|
|
+ /* not ready ==> switch to a waiting state by setting the closure */
|
|
|
+ *st = closure;
|
|
|
+ } else if (*st == CLOSURE_READY) {
|
|
|
+ /* already ready ==> queue the closure to run immediately */
|
|
|
+ *st = CLOSURE_NOT_READY;
|
|
|
+ grpc_exec_ctx_sched(exec_ctx, closure, fd_shutdown_error(fd->shutdown),
|
|
|
+ NULL);
|
|
|
+ } else {
|
|
|
+ /* upcallptr was set to a different closure. This is an error! */
|
|
|
+ gpr_log(GPR_ERROR,
|
|
|
+ "User called a notify_on function with a previous callback still "
|
|
|
+ "pending");
|
|
|
+ abort();
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+/* returns 1 if state becomes not ready */
|
|
|
+static int set_ready_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
|
|
|
+ grpc_closure **st) {
|
|
|
+ if (*st == CLOSURE_READY) {
|
|
|
+ /* duplicate ready ==> ignore */
|
|
|
+ return 0;
|
|
|
+ } else if (*st == CLOSURE_NOT_READY) {
|
|
|
+ /* not ready, and not waiting ==> flag ready */
|
|
|
+ *st = CLOSURE_READY;
|
|
|
+ return 0;
|
|
|
+ } else {
|
|
|
+ /* waiting ==> queue closure */
|
|
|
+ grpc_exec_ctx_sched(exec_ctx, *st, fd_shutdown_error(fd->shutdown), NULL);
|
|
|
+ *st = CLOSURE_NOT_READY;
|
|
|
+ return 1;
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_pollset *fd_get_read_notifier_pollset(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_fd *fd) {
|
|
|
+ grpc_pollset *notifier = NULL;
|
|
|
+
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ notifier = fd->read_notifier_pollset;
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+
|
|
|
+ return notifier;
|
|
|
+}
|
|
|
+
|
|
|
+static bool fd_is_shutdown(grpc_fd *fd) {
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ const bool r = fd->shutdown;
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+ return r;
|
|
|
+}
|
|
|
+
|
|
|
+/* Might be called multiple times */
|
|
|
+static void fd_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd) {
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ /* Do the actual shutdown only once */
|
|
|
+ if (!fd->shutdown) {
|
|
|
+ fd->shutdown = true;
|
|
|
+
|
|
|
+ shutdown(fd->fd, SHUT_RDWR);
|
|
|
+ /* Flush any pending read and write closures. Since fd->shutdown is 'true'
|
|
|
+ at this point, the closures would be called with 'success = false' */
|
|
|
+ set_ready_locked(exec_ctx, fd, &fd->read_closure);
|
|
|
+ set_ready_locked(exec_ctx, fd, &fd->write_closure);
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void fd_notify_on_read(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
|
|
|
+ grpc_closure *closure) {
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ notify_on_locked(exec_ctx, fd, &fd->read_closure, closure);
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void fd_notify_on_write(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
|
|
|
+ grpc_closure *closure) {
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ notify_on_locked(exec_ctx, fd, &fd->write_closure, closure);
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+}
|
|
|
+
|
|
|
+/*******************************************************************************
|
|
|
+ * Pollset Definitions
|
|
|
+ */
|
|
|
+GPR_TLS_DECL(g_current_thread_pollset);
|
|
|
+GPR_TLS_DECL(g_current_thread_worker);
|
|
|
+static __thread bool g_initialized_sigmask;
|
|
|
+static __thread sigset_t g_orig_sigmask;
|
|
|
+
|
|
|
+static void sig_handler(int sig_num) {
|
|
|
+#ifdef GRPC_EPOLL_DEBUG
|
|
|
+ gpr_log(GPR_INFO, "Received signal %d", sig_num);
|
|
|
+#endif
|
|
|
+}
|
|
|
+
|
|
|
+static void poller_kick_init() { signal(grpc_wakeup_signal, sig_handler); }
|
|
|
+
|
|
|
+/* Global state management */
|
|
|
+static grpc_error *pollset_global_init(void) {
|
|
|
+ gpr_tls_init(&g_current_thread_pollset);
|
|
|
+ gpr_tls_init(&g_current_thread_worker);
|
|
|
+ poller_kick_init();
|
|
|
+ return grpc_wakeup_fd_init(&grpc_global_wakeup_fd);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_global_shutdown(void) {
|
|
|
+ grpc_wakeup_fd_destroy(&grpc_global_wakeup_fd);
|
|
|
+ gpr_tls_destroy(&g_current_thread_pollset);
|
|
|
+ gpr_tls_destroy(&g_current_thread_worker);
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_error *pollset_worker_kick(grpc_pollset_worker *worker) {
|
|
|
+ grpc_error *err = GRPC_ERROR_NONE;
|
|
|
+ int err_num = pthread_kill(worker->pt_id, grpc_wakeup_signal);
|
|
|
+ if (err_num != 0) {
|
|
|
+ err = GRPC_OS_ERROR(err_num, "pthread_kill");
|
|
|
+ }
|
|
|
+ return err;
|
|
|
+}
|
|
|
+
|
|
|
+/* Return 1 if the pollset has active threads in pollset_work (pollset must
|
|
|
+ * be locked) */
|
|
|
+static int pollset_has_workers(grpc_pollset *p) {
|
|
|
+ return p->root_worker.next != &p->root_worker;
|
|
|
+}
|
|
|
+
|
|
|
+static void remove_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
|
|
|
+ worker->prev->next = worker->next;
|
|
|
+ worker->next->prev = worker->prev;
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_pollset_worker *pop_front_worker(grpc_pollset *p) {
|
|
|
+ if (pollset_has_workers(p)) {
|
|
|
+ grpc_pollset_worker *w = p->root_worker.next;
|
|
|
+ remove_worker(p, w);
|
|
|
+ return w;
|
|
|
+ } else {
|
|
|
+ return NULL;
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static void push_back_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
|
|
|
+ worker->next = &p->root_worker;
|
|
|
+ worker->prev = worker->next->prev;
|
|
|
+ worker->prev->next = worker->next->prev = worker;
|
|
|
+}
|
|
|
+
|
|
|
+static void push_front_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
|
|
|
+ worker->prev = &p->root_worker;
|
|
|
+ worker->next = worker->prev->next;
|
|
|
+ worker->prev->next = worker->next->prev = worker;
|
|
|
+}
|
|
|
+
|
|
|
+/* p->mu must be held before calling this function */
|
|
|
+static grpc_error *pollset_kick(grpc_pollset *p,
|
|
|
+ grpc_pollset_worker *specific_worker) {
|
|
|
+ GPR_TIMER_BEGIN("pollset_kick", 0);
|
|
|
+ grpc_error *error = GRPC_ERROR_NONE;
|
|
|
+ const char *err_desc = "Kick Failure";
|
|
|
+
|
|
|
+ grpc_pollset_worker *worker = specific_worker;
|
|
|
+ if (worker != NULL) {
|
|
|
+ if (worker == GRPC_POLLSET_KICK_BROADCAST) {
|
|
|
+ if (pollset_has_workers(p)) {
|
|
|
+ GPR_TIMER_BEGIN("pollset_kick.broadcast", 0);
|
|
|
+ for (worker = p->root_worker.next; worker != &p->root_worker;
|
|
|
+ worker = worker->next) {
|
|
|
+ if (gpr_tls_get(&g_current_thread_worker) != (intptr_t)worker) {
|
|
|
+ append_error(&error, pollset_worker_kick(worker), err_desc);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ GPR_TIMER_END("pollset_kick.broadcast", 0);
|
|
|
+ } else {
|
|
|
+ p->kicked_without_pollers = true;
|
|
|
+ }
|
|
|
+ } else {
|
|
|
+ GPR_TIMER_MARK("kicked_specifically", 0);
|
|
|
+ if (gpr_tls_get(&g_current_thread_worker) != (intptr_t)worker) {
|
|
|
+ append_error(&error, pollset_worker_kick(worker), err_desc);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ } else if (gpr_tls_get(&g_current_thread_pollset) != (intptr_t)p) {
|
|
|
+ /* Since worker == NULL, it means that we can kick "any" worker on this
|
|
|
+ pollset 'p'. If 'p' happens to be the same pollset this thread is
|
|
|
+ currently polling (i.e in pollset_work() function), then there is no need
|
|
|
+ to kick any other worker since the current thread can just absorb the
|
|
|
+ kick. This is the reason why we enter this case only when
|
|
|
+ g_current_thread_pollset is != p */
|
|
|
+
|
|
|
+ GPR_TIMER_MARK("kick_anonymous", 0);
|
|
|
+ worker = pop_front_worker(p);
|
|
|
+ if (worker != NULL) {
|
|
|
+ GPR_TIMER_MARK("finally_kick", 0);
|
|
|
+ push_back_worker(p, worker);
|
|
|
+ append_error(&error, pollset_worker_kick(worker), err_desc);
|
|
|
+ } else {
|
|
|
+ GPR_TIMER_MARK("kicked_no_pollers", 0);
|
|
|
+ p->kicked_without_pollers = true;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ GPR_TIMER_END("pollset_kick", 0);
|
|
|
+ GRPC_LOG_IF_ERROR("pollset_kick", GRPC_ERROR_REF(error));
|
|
|
+ return error;
|
|
|
+}
|
|
|
+
|
|
|
+static grpc_error *kick_poller(void) {
|
|
|
+ return grpc_wakeup_fd_wakeup(&grpc_global_wakeup_fd);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_init(grpc_pollset *pollset, gpr_mu **mu) {
|
|
|
+ gpr_mu_init(&pollset->mu);
|
|
|
+ *mu = &pollset->mu;
|
|
|
+
|
|
|
+ pollset->root_worker.next = pollset->root_worker.prev = &pollset->root_worker;
|
|
|
+ pollset->kicked_without_pollers = false;
|
|
|
+
|
|
|
+ pollset->shutting_down = false;
|
|
|
+ pollset->finish_shutdown_called = false;
|
|
|
+ pollset->shutdown_done = NULL;
|
|
|
+
|
|
|
+ pollset->polling_island = NULL;
|
|
|
+}
|
|
|
+
|
|
|
+/* Convert a timespec to milliseconds:
|
|
|
+ - Very small or negative poll times are clamped to zero to do a non-blocking
|
|
|
+ poll (which becomes spin polling)
|
|
|
+ - Other small values are rounded up to one millisecond
|
|
|
+ - Longer than a millisecond polls are rounded up to the next nearest
|
|
|
+ millisecond to avoid spinning
|
|
|
+ - Infinite timeouts are converted to -1 */
|
|
|
+static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
|
|
|
+ gpr_timespec now) {
|
|
|
+ gpr_timespec timeout;
|
|
|
+ static const int64_t max_spin_polling_us = 10;
|
|
|
+ if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
|
|
|
+ return -1;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (gpr_time_cmp(deadline, gpr_time_add(now, gpr_time_from_micros(
|
|
|
+ max_spin_polling_us,
|
|
|
+ GPR_TIMESPAN))) <= 0) {
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+ timeout = gpr_time_sub(deadline, now);
|
|
|
+ return gpr_time_to_millis(gpr_time_add(
|
|
|
+ timeout, gpr_time_from_nanos(GPR_NS_PER_MS - 1, GPR_TIMESPAN)));
|
|
|
+}
|
|
|
+
|
|
|
+static void fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
|
|
|
+ grpc_pollset *notifier) {
|
|
|
+ /* Need the fd->mu since we might be racing with fd_notify_on_read */
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ set_ready_locked(exec_ctx, fd, &fd->read_closure);
|
|
|
+ fd->read_notifier_pollset = notifier;
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void fd_become_writable(grpc_exec_ctx *exec_ctx, grpc_fd *fd) {
|
|
|
+ /* Need the fd->mu since we might be racing with fd_notify_on_write */
|
|
|
+ gpr_mu_lock(&fd->mu);
|
|
|
+ set_ready_locked(exec_ctx, fd, &fd->write_closure);
|
|
|
+ gpr_mu_unlock(&fd->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_release_polling_island(grpc_pollset *ps, char *reason) {
|
|
|
+ if (ps->polling_island != NULL) {
|
|
|
+ PI_UNREF(ps->polling_island, reason);
|
|
|
+ }
|
|
|
+ ps->polling_island = NULL;
|
|
|
+}
|
|
|
+
|
|
|
+static void finish_shutdown_locked(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset *pollset) {
|
|
|
+ /* The pollset cannot have any workers if we are at this stage */
|
|
|
+ GPR_ASSERT(!pollset_has_workers(pollset));
|
|
|
+
|
|
|
+ pollset->finish_shutdown_called = true;
|
|
|
+
|
|
|
+ /* Release the ref and set pollset->polling_island to NULL */
|
|
|
+ pollset_release_polling_island(pollset, "ps_shutdown");
|
|
|
+ grpc_exec_ctx_sched(exec_ctx, pollset->shutdown_done, GRPC_ERROR_NONE, NULL);
|
|
|
+}
|
|
|
+
|
|
|
+/* pollset->mu lock must be held by the caller before calling this */
|
|
|
+static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
|
|
|
+ grpc_closure *closure) {
|
|
|
+ GPR_TIMER_BEGIN("pollset_shutdown", 0);
|
|
|
+ GPR_ASSERT(!pollset->shutting_down);
|
|
|
+ pollset->shutting_down = true;
|
|
|
+ pollset->shutdown_done = closure;
|
|
|
+ pollset_kick(pollset, GRPC_POLLSET_KICK_BROADCAST);
|
|
|
+
|
|
|
+ /* If the pollset has any workers, we cannot call finish_shutdown_locked()
|
|
|
+ because it would release the underlying polling island. In such a case, we
|
|
|
+ let the last worker call finish_shutdown_locked() from pollset_work() */
|
|
|
+ if (!pollset_has_workers(pollset)) {
|
|
|
+ GPR_ASSERT(!pollset->finish_shutdown_called);
|
|
|
+ GPR_TIMER_MARK("pollset_shutdown.finish_shutdown_locked", 0);
|
|
|
+ finish_shutdown_locked(exec_ctx, pollset);
|
|
|
+ }
|
|
|
+ GPR_TIMER_END("pollset_shutdown", 0);
|
|
|
+}
|
|
|
+
|
|
|
+/* pollset_shutdown is guaranteed to be called before pollset_destroy. So other
|
|
|
+ * than destroying the mutexes, there is nothing special that needs to be done
|
|
|
+ * here */
|
|
|
+static void pollset_destroy(grpc_pollset *pollset) {
|
|
|
+ GPR_ASSERT(!pollset_has_workers(pollset));
|
|
|
+ gpr_mu_destroy(&pollset->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_reset(grpc_pollset *pollset) {
|
|
|
+ GPR_ASSERT(pollset->shutting_down);
|
|
|
+ GPR_ASSERT(!pollset_has_workers(pollset));
|
|
|
+ pollset->shutting_down = false;
|
|
|
+ pollset->finish_shutdown_called = false;
|
|
|
+ pollset->kicked_without_pollers = false;
|
|
|
+ pollset->shutdown_done = NULL;
|
|
|
+ pollset_release_polling_island(pollset, "ps_reset");
|
|
|
+}
|
|
|
+
|
|
|
+#define GRPC_EPOLL_MAX_EVENTS 1000
|
|
|
+/* Note: sig_mask contains the signal mask to use *during* epoll_wait() */
|
|
|
+static void pollset_work_and_unlock(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset *pollset, int timeout_ms,
|
|
|
+ sigset_t *sig_mask, grpc_error **error) {
|
|
|
+ struct epoll_event ep_ev[GRPC_EPOLL_MAX_EVENTS];
|
|
|
+ int epoll_fd = -1;
|
|
|
+ int ep_rv;
|
|
|
+ polling_island *pi = NULL;
|
|
|
+ char *err_msg;
|
|
|
+ const char *err_desc = "pollset_work_and_unlock";
|
|
|
+ GPR_TIMER_BEGIN("pollset_work_and_unlock", 0);
|
|
|
+
|
|
|
+ /* We need to get the epoll_fd to wait on. The epoll_fd is in inside the
|
|
|
+ latest polling island pointed by pollset->polling_island.
|
|
|
+
|
|
|
+ Since epoll_fd is immutable, we can read it without obtaining the polling
|
|
|
+ island lock. There is however a possibility that the polling island (from
|
|
|
+ which we got the epoll_fd) got merged with another island while we are
|
|
|
+ in this function. This is still okay because in such a case, we will wakeup
|
|
|
+ right-away from epoll_wait() and pick up the latest polling_island the next
|
|
|
+ this function (i.e pollset_work_and_unlock()) is called */
|
|
|
+
|
|
|
+ if (pollset->polling_island == NULL) {
|
|
|
+ pollset->polling_island = polling_island_create(NULL, error);
|
|
|
+ if (pollset->polling_island == NULL) {
|
|
|
+ GPR_TIMER_END("pollset_work_and_unlock", 0);
|
|
|
+ return; /* Fatal error. We cannot continue */
|
|
|
+ }
|
|
|
+
|
|
|
+ PI_ADD_REF(pollset->polling_island, "ps");
|
|
|
+ }
|
|
|
+
|
|
|
+ pi = polling_island_maybe_get_latest(pollset->polling_island);
|
|
|
+ epoll_fd = pi->epoll_fd;
|
|
|
+
|
|
|
+ /* Update the pollset->polling_island since the island being pointed by
|
|
|
+ pollset->polling_island maybe older than the one pointed by pi) */
|
|
|
+ if (pollset->polling_island != pi) {
|
|
|
+ /* Always do PI_ADD_REF before PI_UNREF because PI_UNREF may cause the
|
|
|
+ polling island to be deleted */
|
|
|
+ PI_ADD_REF(pi, "ps");
|
|
|
+ PI_UNREF(pollset->polling_island, "ps");
|
|
|
+ pollset->polling_island = pi;
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Add an extra ref so that the island does not get destroyed (which means
|
|
|
+ the epoll_fd won't be closed) while we are are doing an epoll_wait() on the
|
|
|
+ epoll_fd */
|
|
|
+ PI_ADD_REF(pi, "ps_work");
|
|
|
+ gpr_mu_unlock(&pollset->mu);
|
|
|
+
|
|
|
+ do {
|
|
|
+ ep_rv = epoll_pwait(epoll_fd, ep_ev, GRPC_EPOLL_MAX_EVENTS, timeout_ms,
|
|
|
+ sig_mask);
|
|
|
+ if (ep_rv < 0) {
|
|
|
+ if (errno != EINTR) {
|
|
|
+ gpr_asprintf(&err_msg,
|
|
|
+ "epoll_wait() epoll fd: %d failed with error: %d (%s)",
|
|
|
+ epoll_fd, errno, strerror(errno));
|
|
|
+ append_error(error, GRPC_OS_ERROR(errno, err_msg), err_desc);
|
|
|
+ } else {
|
|
|
+ /* We were interrupted. Save an interation by doing a zero timeout
|
|
|
+ epoll_wait to see if there are any other events of interest */
|
|
|
+ ep_rv = epoll_wait(epoll_fd, ep_ev, GRPC_EPOLL_MAX_EVENTS, 0);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+#ifdef GRPC_TSAN
|
|
|
+ /* See the definition of g_poll_sync for more details */
|
|
|
+ gpr_atm_acq_load(&g_epoll_sync);
|
|
|
+#endif /* defined(GRPC_TSAN) */
|
|
|
+
|
|
|
+ for (int i = 0; i < ep_rv; ++i) {
|
|
|
+ void *data_ptr = ep_ev[i].data.ptr;
|
|
|
+ if (data_ptr == &grpc_global_wakeup_fd) {
|
|
|
+ append_error(error,
|
|
|
+ grpc_wakeup_fd_consume_wakeup(&grpc_global_wakeup_fd),
|
|
|
+ err_desc);
|
|
|
+ } else if (data_ptr == &polling_island_wakeup_fd) {
|
|
|
+ /* This means that our polling island is merged with a different
|
|
|
+ island. We do not have to do anything here since the subsequent call
|
|
|
+ to the function pollset_work_and_unlock() will pick up the correct
|
|
|
+ epoll_fd */
|
|
|
+ } else {
|
|
|
+ grpc_fd *fd = data_ptr;
|
|
|
+ int cancel = ep_ev[i].events & (EPOLLERR | EPOLLHUP);
|
|
|
+ int read_ev = ep_ev[i].events & (EPOLLIN | EPOLLPRI);
|
|
|
+ int write_ev = ep_ev[i].events & EPOLLOUT;
|
|
|
+ if (read_ev || cancel) {
|
|
|
+ fd_become_readable(exec_ctx, fd, pollset);
|
|
|
+ }
|
|
|
+ if (write_ev || cancel) {
|
|
|
+ fd_become_writable(exec_ctx, fd);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ }
|
|
|
+ } while (ep_rv == GRPC_EPOLL_MAX_EVENTS);
|
|
|
+
|
|
|
+ GPR_ASSERT(pi != NULL);
|
|
|
+
|
|
|
+ /* Before leaving, release the extra ref we added to the polling island. It
|
|
|
+ is important to use "pi" here (i.e our old copy of pollset->polling_island
|
|
|
+ that we got before releasing the polling island lock). This is because
|
|
|
+ pollset->polling_island pointer might get udpated in other parts of the
|
|
|
+ code when there is an island merge while we are doing epoll_wait() above */
|
|
|
+ PI_UNREF(pi, "ps_work");
|
|
|
+
|
|
|
+ GPR_TIMER_END("pollset_work_and_unlock", 0);
|
|
|
+}
|
|
|
+
|
|
|
+/* pollset->mu lock must be held by the caller before calling this.
|
|
|
+ The function pollset_work() may temporarily release the lock (pollset->mu)
|
|
|
+ during the course of its execution but it will always re-acquire the lock and
|
|
|
+ ensure that it is held by the time the function returns */
|
|
|
+static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
|
|
|
+ grpc_pollset_worker **worker_hdl,
|
|
|
+ gpr_timespec now, gpr_timespec deadline) {
|
|
|
+ GPR_TIMER_BEGIN("pollset_work", 0);
|
|
|
+ grpc_error *error = GRPC_ERROR_NONE;
|
|
|
+ int timeout_ms = poll_deadline_to_millis_timeout(deadline, now);
|
|
|
+
|
|
|
+ sigset_t new_mask;
|
|
|
+
|
|
|
+ grpc_pollset_worker worker;
|
|
|
+ worker.next = worker.prev = NULL;
|
|
|
+ worker.pt_id = pthread_self();
|
|
|
+
|
|
|
+ *worker_hdl = &worker;
|
|
|
+
|
|
|
+ gpr_tls_set(&g_current_thread_pollset, (intptr_t)pollset);
|
|
|
+ gpr_tls_set(&g_current_thread_worker, (intptr_t)&worker);
|
|
|
+
|
|
|
+ if (pollset->kicked_without_pollers) {
|
|
|
+ /* If the pollset was kicked without pollers, pretend that the current
|
|
|
+ worker got the kick and skip polling. A kick indicates that there is some
|
|
|
+ work that needs attention like an event on the completion queue or an
|
|
|
+ alarm */
|
|
|
+ GPR_TIMER_MARK("pollset_work.kicked_without_pollers", 0);
|
|
|
+ pollset->kicked_without_pollers = 0;
|
|
|
+ } else if (!pollset->shutting_down) {
|
|
|
+ /* We use the posix-signal with number 'grpc_wakeup_signal' for waking up
|
|
|
+ (i.e 'kicking') a worker in the pollset.
|
|
|
+ A 'kick' is a way to inform that worker that there is some pending work
|
|
|
+ that needs immediate attention (like an event on the completion queue,
|
|
|
+ or a polling island merge that results in a new epoll-fd to wait on) and
|
|
|
+ that the worker should not spend time waiting in epoll_pwait().
|
|
|
+
|
|
|
+ A kick can come at anytime (i.e before/during or after the worker calls
|
|
|
+ epoll_pwait()) but in all cases we have to make sure that when a worker
|
|
|
+ gets a kick, it does not spend time in epoll_pwait(). In other words, one
|
|
|
+ kick should result in skipping/exiting of one epoll_pwait();
|
|
|
+
|
|
|
+ To accomplish this, we mask 'grpc_wakeup_signal' on this worker at all
|
|
|
+ times *except* when it is in epoll_pwait(). This way, the worker never
|
|
|
+ misses acting on a kick */
|
|
|
+
|
|
|
+ if (!g_initialized_sigmask) {
|
|
|
+ sigemptyset(&new_mask);
|
|
|
+ sigaddset(&new_mask, grpc_wakeup_signal);
|
|
|
+ pthread_sigmask(SIG_BLOCK, &new_mask, &g_orig_sigmask);
|
|
|
+ sigdelset(&g_orig_sigmask, grpc_wakeup_signal);
|
|
|
+ g_initialized_sigmask = true;
|
|
|
+ /* new_mask: The new thread mask which blocks 'grpc_wakeup_signal'.
|
|
|
+ This is the mask used at all times *except during
|
|
|
+ epoll_wait()*"
|
|
|
+ g_orig_sigmask: The thread mask which allows 'grpc_wakeup_signal' and
|
|
|
+ this is the mask to use *during epoll_wait()*
|
|
|
+
|
|
|
+ The new_mask is set on the worker before it is added to the pollset
|
|
|
+ (i.e before it can be kicked) */
|
|
|
+ }
|
|
|
+
|
|
|
+ push_front_worker(pollset, &worker); /* Add worker to pollset */
|
|
|
+
|
|
|
+ pollset_work_and_unlock(exec_ctx, pollset, timeout_ms, &g_orig_sigmask,
|
|
|
+ &error);
|
|
|
+ grpc_exec_ctx_flush(exec_ctx);
|
|
|
+
|
|
|
+ gpr_mu_lock(&pollset->mu);
|
|
|
+ remove_worker(pollset, &worker);
|
|
|
+ }
|
|
|
+
|
|
|
+ /* If we are the last worker on the pollset (i.e pollset_has_workers() is
|
|
|
+ false at this point) and the pollset is shutting down, we may have to
|
|
|
+ finish the shutdown process by calling finish_shutdown_locked().
|
|
|
+ See pollset_shutdown() for more details.
|
|
|
+
|
|
|
+ Note: Continuing to access pollset here is safe; it is the caller's
|
|
|
+ responsibility to not destroy a pollset when it has outstanding calls to
|
|
|
+ pollset_work() */
|
|
|
+ if (pollset->shutting_down && !pollset_has_workers(pollset) &&
|
|
|
+ !pollset->finish_shutdown_called) {
|
|
|
+ GPR_TIMER_MARK("pollset_work.finish_shutdown_locked", 0);
|
|
|
+ finish_shutdown_locked(exec_ctx, pollset);
|
|
|
+
|
|
|
+ gpr_mu_unlock(&pollset->mu);
|
|
|
+ grpc_exec_ctx_flush(exec_ctx);
|
|
|
+ gpr_mu_lock(&pollset->mu);
|
|
|
+ }
|
|
|
+
|
|
|
+ *worker_hdl = NULL;
|
|
|
+
|
|
|
+ gpr_tls_set(&g_current_thread_pollset, (intptr_t)0);
|
|
|
+ gpr_tls_set(&g_current_thread_worker, (intptr_t)0);
|
|
|
+
|
|
|
+ GPR_TIMER_END("pollset_work", 0);
|
|
|
+
|
|
|
+ GRPC_LOG_IF_ERROR("pollset_work", GRPC_ERROR_REF(error));
|
|
|
+ return error;
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
|
|
|
+ grpc_fd *fd) {
|
|
|
+ grpc_error *error = GRPC_ERROR_NONE;
|
|
|
+
|
|
|
+ gpr_mu_lock(&pollset->mu);
|
|
|
+ gpr_mu_lock(&fd->pi_mu);
|
|
|
+
|
|
|
+ polling_island *pi_new = NULL;
|
|
|
+
|
|
|
+ /* 1) If fd->polling_island and pollset->polling_island are both non-NULL and
|
|
|
+ * equal, do nothing.
|
|
|
+ * 2) If fd->polling_island and pollset->polling_island are both NULL, create
|
|
|
+ * a new polling island (with a refcount of 2) and make the polling_island
|
|
|
+ * fields in both fd and pollset to point to the new island
|
|
|
+ * 3) If one of fd->polling_island or pollset->polling_island is NULL, update
|
|
|
+ * the NULL polling_island field to point to the non-NULL polling_island
|
|
|
+ * field (ensure that the refcount on the polling island is incremented by
|
|
|
+ * 1 to account for the newly added reference)
|
|
|
+ * 4) Finally, if fd->polling_island and pollset->polling_island are non-NULL
|
|
|
+ * and different, merge both the polling islands and update the
|
|
|
+ * polling_island fields in both fd and pollset to point to the merged
|
|
|
+ * polling island.
|
|
|
+ */
|
|
|
+ if (fd->polling_island == pollset->polling_island) {
|
|
|
+ pi_new = fd->polling_island;
|
|
|
+ if (pi_new == NULL) {
|
|
|
+ pi_new = polling_island_create(fd, &error);
|
|
|
+ }
|
|
|
+ } else if (fd->polling_island == NULL) {
|
|
|
+ pi_new = polling_island_lock(pollset->polling_island);
|
|
|
+ polling_island_add_fds_locked(pi_new, &fd, 1, true, &error);
|
|
|
+ gpr_mu_unlock(&pi_new->mu);
|
|
|
+ } else if (pollset->polling_island == NULL) {
|
|
|
+ pi_new = polling_island_lock(fd->polling_island);
|
|
|
+ gpr_mu_unlock(&pi_new->mu);
|
|
|
+ } else {
|
|
|
+ pi_new = polling_island_merge(fd->polling_island, pollset->polling_island,
|
|
|
+ &error);
|
|
|
+ }
|
|
|
+
|
|
|
+ /* At this point, pi_new is the polling island that both fd->polling_island
|
|
|
+ and pollset->polling_island must be pointing to */
|
|
|
+
|
|
|
+ if (fd->polling_island != pi_new) {
|
|
|
+ PI_ADD_REF(pi_new, "fd");
|
|
|
+ if (fd->polling_island != NULL) {
|
|
|
+ PI_UNREF(fd->polling_island, "fd");
|
|
|
+ }
|
|
|
+ fd->polling_island = pi_new;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (pollset->polling_island != pi_new) {
|
|
|
+ PI_ADD_REF(pi_new, "ps");
|
|
|
+ if (pollset->polling_island != NULL) {
|
|
|
+ PI_UNREF(pollset->polling_island, "ps");
|
|
|
+ }
|
|
|
+ pollset->polling_island = pi_new;
|
|
|
+ }
|
|
|
+
|
|
|
+ gpr_mu_unlock(&fd->pi_mu);
|
|
|
+ gpr_mu_unlock(&pollset->mu);
|
|
|
+}
|
|
|
+
|
|
|
+/*******************************************************************************
|
|
|
+ * Pollset-set Definitions
|
|
|
+ */
|
|
|
+
|
|
|
+static grpc_pollset_set *pollset_set_create(void) {
|
|
|
+ grpc_pollset_set *pollset_set = gpr_malloc(sizeof(*pollset_set));
|
|
|
+ memset(pollset_set, 0, sizeof(*pollset_set));
|
|
|
+ gpr_mu_init(&pollset_set->mu);
|
|
|
+ return pollset_set;
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_destroy(grpc_pollset_set *pollset_set) {
|
|
|
+ size_t i;
|
|
|
+ gpr_mu_destroy(&pollset_set->mu);
|
|
|
+ for (i = 0; i < pollset_set->fd_count; i++) {
|
|
|
+ GRPC_FD_UNREF(pollset_set->fds[i], "pollset_set");
|
|
|
+ }
|
|
|
+ gpr_free(pollset_set->pollsets);
|
|
|
+ gpr_free(pollset_set->pollset_sets);
|
|
|
+ gpr_free(pollset_set->fds);
|
|
|
+ gpr_free(pollset_set);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_add_fd(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset_set *pollset_set, grpc_fd *fd) {
|
|
|
+ size_t i;
|
|
|
+ gpr_mu_lock(&pollset_set->mu);
|
|
|
+ if (pollset_set->fd_count == pollset_set->fd_capacity) {
|
|
|
+ pollset_set->fd_capacity = GPR_MAX(8, 2 * pollset_set->fd_capacity);
|
|
|
+ pollset_set->fds = gpr_realloc(
|
|
|
+ pollset_set->fds, pollset_set->fd_capacity * sizeof(*pollset_set->fds));
|
|
|
+ }
|
|
|
+ GRPC_FD_REF(fd, "pollset_set");
|
|
|
+ pollset_set->fds[pollset_set->fd_count++] = fd;
|
|
|
+ for (i = 0; i < pollset_set->pollset_count; i++) {
|
|
|
+ pollset_add_fd(exec_ctx, pollset_set->pollsets[i], fd);
|
|
|
+ }
|
|
|
+ for (i = 0; i < pollset_set->pollset_set_count; i++) {
|
|
|
+ pollset_set_add_fd(exec_ctx, pollset_set->pollset_sets[i], fd);
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&pollset_set->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_del_fd(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset_set *pollset_set, grpc_fd *fd) {
|
|
|
+ size_t i;
|
|
|
+ gpr_mu_lock(&pollset_set->mu);
|
|
|
+ for (i = 0; i < pollset_set->fd_count; i++) {
|
|
|
+ if (pollset_set->fds[i] == fd) {
|
|
|
+ pollset_set->fd_count--;
|
|
|
+ GPR_SWAP(grpc_fd *, pollset_set->fds[i],
|
|
|
+ pollset_set->fds[pollset_set->fd_count]);
|
|
|
+ GRPC_FD_UNREF(fd, "pollset_set");
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ for (i = 0; i < pollset_set->pollset_set_count; i++) {
|
|
|
+ pollset_set_del_fd(exec_ctx, pollset_set->pollset_sets[i], fd);
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&pollset_set->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_add_pollset(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset_set *pollset_set,
|
|
|
+ grpc_pollset *pollset) {
|
|
|
+ size_t i, j;
|
|
|
+ gpr_mu_lock(&pollset_set->mu);
|
|
|
+ if (pollset_set->pollset_count == pollset_set->pollset_capacity) {
|
|
|
+ pollset_set->pollset_capacity =
|
|
|
+ GPR_MAX(8, 2 * pollset_set->pollset_capacity);
|
|
|
+ pollset_set->pollsets =
|
|
|
+ gpr_realloc(pollset_set->pollsets, pollset_set->pollset_capacity *
|
|
|
+ sizeof(*pollset_set->pollsets));
|
|
|
+ }
|
|
|
+ pollset_set->pollsets[pollset_set->pollset_count++] = pollset;
|
|
|
+ for (i = 0, j = 0; i < pollset_set->fd_count; i++) {
|
|
|
+ if (fd_is_orphaned(pollset_set->fds[i])) {
|
|
|
+ GRPC_FD_UNREF(pollset_set->fds[i], "pollset_set");
|
|
|
+ } else {
|
|
|
+ pollset_add_fd(exec_ctx, pollset, pollset_set->fds[i]);
|
|
|
+ pollset_set->fds[j++] = pollset_set->fds[i];
|
|
|
+ }
|
|
|
+ }
|
|
|
+ pollset_set->fd_count = j;
|
|
|
+ gpr_mu_unlock(&pollset_set->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_del_pollset(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset_set *pollset_set,
|
|
|
+ grpc_pollset *pollset) {
|
|
|
+ size_t i;
|
|
|
+ gpr_mu_lock(&pollset_set->mu);
|
|
|
+ for (i = 0; i < pollset_set->pollset_count; i++) {
|
|
|
+ if (pollset_set->pollsets[i] == pollset) {
|
|
|
+ pollset_set->pollset_count--;
|
|
|
+ GPR_SWAP(grpc_pollset *, pollset_set->pollsets[i],
|
|
|
+ pollset_set->pollsets[pollset_set->pollset_count]);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&pollset_set->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_add_pollset_set(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset_set *bag,
|
|
|
+ grpc_pollset_set *item) {
|
|
|
+ size_t i, j;
|
|
|
+ gpr_mu_lock(&bag->mu);
|
|
|
+ if (bag->pollset_set_count == bag->pollset_set_capacity) {
|
|
|
+ bag->pollset_set_capacity = GPR_MAX(8, 2 * bag->pollset_set_capacity);
|
|
|
+ bag->pollset_sets =
|
|
|
+ gpr_realloc(bag->pollset_sets,
|
|
|
+ bag->pollset_set_capacity * sizeof(*bag->pollset_sets));
|
|
|
+ }
|
|
|
+ bag->pollset_sets[bag->pollset_set_count++] = item;
|
|
|
+ for (i = 0, j = 0; i < bag->fd_count; i++) {
|
|
|
+ if (fd_is_orphaned(bag->fds[i])) {
|
|
|
+ GRPC_FD_UNREF(bag->fds[i], "pollset_set");
|
|
|
+ } else {
|
|
|
+ pollset_set_add_fd(exec_ctx, item, bag->fds[i]);
|
|
|
+ bag->fds[j++] = bag->fds[i];
|
|
|
+ }
|
|
|
+ }
|
|
|
+ bag->fd_count = j;
|
|
|
+ gpr_mu_unlock(&bag->mu);
|
|
|
+}
|
|
|
+
|
|
|
+static void pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx,
|
|
|
+ grpc_pollset_set *bag,
|
|
|
+ grpc_pollset_set *item) {
|
|
|
+ size_t i;
|
|
|
+ gpr_mu_lock(&bag->mu);
|
|
|
+ for (i = 0; i < bag->pollset_set_count; i++) {
|
|
|
+ if (bag->pollset_sets[i] == item) {
|
|
|
+ bag->pollset_set_count--;
|
|
|
+ GPR_SWAP(grpc_pollset_set *, bag->pollset_sets[i],
|
|
|
+ bag->pollset_sets[bag->pollset_set_count]);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ gpr_mu_unlock(&bag->mu);
|
|
|
+}
|
|
|
+
|
|
|
+/* Test helper functions
|
|
|
+ * */
|
|
|
+void *grpc_fd_get_polling_island(grpc_fd *fd) {
|
|
|
+ polling_island *pi;
|
|
|
+
|
|
|
+ gpr_mu_lock(&fd->pi_mu);
|
|
|
+ pi = fd->polling_island;
|
|
|
+ gpr_mu_unlock(&fd->pi_mu);
|
|
|
+
|
|
|
+ return pi;
|
|
|
+}
|
|
|
+
|
|
|
+void *grpc_pollset_get_polling_island(grpc_pollset *ps) {
|
|
|
+ polling_island *pi;
|
|
|
+
|
|
|
+ gpr_mu_lock(&ps->mu);
|
|
|
+ pi = ps->polling_island;
|
|
|
+ gpr_mu_unlock(&ps->mu);
|
|
|
+
|
|
|
+ return pi;
|
|
|
+}
|
|
|
+
|
|
|
+bool grpc_are_polling_islands_equal(void *p, void *q) {
|
|
|
+ polling_island *p1 = p;
|
|
|
+ polling_island *p2 = q;
|
|
|
+
|
|
|
+ /* Note: polling_island_lock_pair() may change p1 and p2 to point to the
|
|
|
+ latest polling islands in their respective linked lists */
|
|
|
+ polling_island_lock_pair(&p1, &p2);
|
|
|
+ polling_island_unlock_pair(p1, p2);
|
|
|
+
|
|
|
+ return p1 == p2;
|
|
|
+}
|
|
|
+
|
|
|
+/*******************************************************************************
|
|
|
+ * Event engine binding
|
|
|
+ */
|
|
|
+
|
|
|
+static void shutdown_engine(void) {
|
|
|
+ fd_global_shutdown();
|
|
|
+ pollset_global_shutdown();
|
|
|
+ polling_island_global_shutdown();
|
|
|
+}
|
|
|
+
|
|
|
+static const grpc_event_engine_vtable vtable = {
|
|
|
+ .pollset_size = sizeof(grpc_pollset),
|
|
|
+
|
|
|
+ .fd_create = fd_create,
|
|
|
+ .fd_wrapped_fd = fd_wrapped_fd,
|
|
|
+ .fd_orphan = fd_orphan,
|
|
|
+ .fd_shutdown = fd_shutdown,
|
|
|
+ .fd_is_shutdown = fd_is_shutdown,
|
|
|
+ .fd_notify_on_read = fd_notify_on_read,
|
|
|
+ .fd_notify_on_write = fd_notify_on_write,
|
|
|
+ .fd_get_read_notifier_pollset = fd_get_read_notifier_pollset,
|
|
|
+
|
|
|
+ .pollset_init = pollset_init,
|
|
|
+ .pollset_shutdown = pollset_shutdown,
|
|
|
+ .pollset_reset = pollset_reset,
|
|
|
+ .pollset_destroy = pollset_destroy,
|
|
|
+ .pollset_work = pollset_work,
|
|
|
+ .pollset_kick = pollset_kick,
|
|
|
+ .pollset_add_fd = pollset_add_fd,
|
|
|
+
|
|
|
+ .pollset_set_create = pollset_set_create,
|
|
|
+ .pollset_set_destroy = pollset_set_destroy,
|
|
|
+ .pollset_set_add_pollset = pollset_set_add_pollset,
|
|
|
+ .pollset_set_del_pollset = pollset_set_del_pollset,
|
|
|
+ .pollset_set_add_pollset_set = pollset_set_add_pollset_set,
|
|
|
+ .pollset_set_del_pollset_set = pollset_set_del_pollset_set,
|
|
|
+ .pollset_set_add_fd = pollset_set_add_fd,
|
|
|
+ .pollset_set_del_fd = pollset_set_del_fd,
|
|
|
+
|
|
|
+ .kick_poller = kick_poller,
|
|
|
+
|
|
|
+ .shutdown_engine = shutdown_engine,
|
|
|
+};
|
|
|
+
|
|
|
+/* It is possible that GLIBC has epoll but the underlying kernel doesn't.
|
|
|
+ * Create a dummy epoll_fd to make sure epoll support is available */
|
|
|
+static bool is_epoll_available() {
|
|
|
+ int fd = epoll_create1(EPOLL_CLOEXEC);
|
|
|
+ if (fd < 0) {
|
|
|
+ gpr_log(
|
|
|
+ GPR_ERROR,
|
|
|
+ "epoll_create1 failed with error: %d. Not using epoll polling engine",
|
|
|
+ fd);
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ close(fd);
|
|
|
+ return true;
|
|
|
+}
|
|
|
+
|
|
|
+const grpc_event_engine_vtable *grpc_init_epoll_linux(void) {
|
|
|
+ /* If use of signals is disabled, we cannot use epoll engine*/
|
|
|
+ if (is_grpc_wakeup_signal_initialized && grpc_wakeup_signal < 0) {
|
|
|
+ return NULL;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (!is_epoll_available()) {
|
|
|
+ return NULL;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (!is_grpc_wakeup_signal_initialized) {
|
|
|
+ grpc_use_signal(SIGRTMIN + 2);
|
|
|
+ }
|
|
|
+
|
|
|
+ fd_global_init();
|
|
|
+
|
|
|
+ if (!GRPC_LOG_IF_ERROR("pollset_global_init", pollset_global_init())) {
|
|
|
+ return NULL;
|
|
|
+ }
|
|
|
+
|
|
|
+ if (!GRPC_LOG_IF_ERROR("polling_island_global_init",
|
|
|
+ polling_island_global_init())) {
|
|
|
+ return NULL;
|
|
|
+ }
|
|
|
+
|
|
|
+ return &vtable;
|
|
|
+}
|
|
|
+
|
|
|
+#else /* defined(GPR_LINUX_EPOLL) */
|
|
|
+#if defined(GPR_POSIX_SOCKET)
|
|
|
+#include "src/core/lib/iomgr/ev_posix.h"
|
|
|
+/* If GPR_LINUX_EPOLL is not defined, it means epoll is not available. Return
|
|
|
+ * NULL */
|
|
|
+const grpc_event_engine_vtable *grpc_init_epoll_linux(void) { return NULL; }
|
|
|
+#endif /* defined(GPR_POSIX_SOCKET) */
|
|
|
+
|
|
|
+void grpc_use_signal(int signum) {}
|
|
|
+#endif /* !defined(GPR_LINUX_EPOLL) */
|
yang-g