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authorAnand Avati <avati@redhat.com>2013-07-19 08:31:41 -0700
committerVijay Bellur <vbellur@redhat.com>2013-07-23 06:11:12 -0700
commit37ac6bdca826046cbcb0d50727af29baf9407950 (patch)
treeb899eb81a70c7719c5d7e4328697cc314da24b97 /xlators/storage
parentcee1f9b5c7917bba220f1156b342bf07cac4ad38 (diff)
storage/posix: implement batched fsync in a single thread
Because of the extra fsync()s issued by AFR transaction, they could potentially "clog" all the io-threads denying unrelated operations from making progress. This patch assigns a dedicated thread to issues fsyncs, as an experimental feature to understand performance characteristics with the approach. As a basis, incoming individual fsync requests are grouped into batches, falling in the same @batch-fsync-delay-usec window of time. These windows can extend in practice, as processing of the previous batch can take longer than @batch-fsync-delay-usec while new requests are getting batched. The feature support three modes (similar to the -S modes of fs_mark) - syncfs: In this mode one syncfs() is issued per batch, instead of N fsync()s (one per file.) - syncfs-single-fsync: In this mode one syncfs() is issued per batch (which, on Linux, guarantees the completion of write-out of dirty pages in the filesystem up to that point) and one single fsync() to synchronize or flush the controller/drive cache. This corresponds to -S 2 of fsmark. - syncfs-reverse-fsync: In this mode, one syncfs() is issued per batch, and all the open files in that batch are fsync()'ed in the reverse order of the queue. This corresponds to -S 4 of fsmark. - reverse-fsync: In this mode, no syncfs() is issued and all the files in the batch are fsync()'ed in the reverse order. This corresponds to -S 3 of fsmark. Change-Id: Ia1e170a810c780c8d80e02cf910accc4170c4cd4 BUG: 927146 Signed-off-by: Anand Avati <avati@redhat.com> Reviewed-on: http://review.gluster.org/4746 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Diffstat (limited to 'xlators/storage')
-rw-r--r--xlators/storage/posix/src/posix-helpers.c140
-rw-r--r--xlators/storage/posix/src/posix.c111
-rw-r--r--xlators/storage/posix/src/posix.h19
3 files changed, 270 insertions, 0 deletions
diff --git a/xlators/storage/posix/src/posix-helpers.c b/xlators/storage/posix/src/posix-helpers.c
index a13e020..0c0fdba 100644
--- a/xlators/storage/posix/src/posix-helpers.c
+++ b/xlators/storage/posix/src/posix-helpers.c
@@ -1177,3 +1177,143 @@ posix_spawn_health_check_thread (xlator_t *xl)
unlock:
UNLOCK (&priv->lock);
}
+
+int
+posix_fsyncer_pick (xlator_t *this, struct list_head *head)
+{
+ struct posix_private *priv = NULL;
+ int count = 0;
+
+ priv = this->private;
+ pthread_mutex_lock (&priv->fsync_mutex);
+ {
+ while (list_empty (&priv->fsyncs))
+ pthread_cond_wait (&priv->fsync_cond,
+ &priv->fsync_mutex);
+
+ count = priv->fsync_queue_count;
+ priv->fsync_queue_count = 0;
+ list_splice_init (&priv->fsyncs, head);
+ }
+ pthread_mutex_unlock (&priv->fsync_mutex);
+
+ return count;
+}
+
+
+void
+posix_fsyncer_process (xlator_t *this, call_stub_t *stub, gf_boolean_t do_fsync)
+{
+ struct posix_fd *pfd = NULL;
+ int ret = -1;
+ struct posix_private *priv = NULL;
+
+ priv = this->private;
+
+ ret = posix_fd_ctx_get (stub->args.fd, this, &pfd);
+ if (ret < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "could not get fdctx for fd(%s)",
+ uuid_utoa (stub->args.fd->inode->gfid));
+ call_unwind_error (stub, -1, EINVAL);
+ return;
+ }
+
+ if (do_fsync) {
+#ifdef HAVE_FDATASYNC
+ if (stub->args.datasync)
+ ret = fdatasync (pfd->fd);
+ else
+#endif
+ ret = fsync (pfd->fd);
+ } else {
+ ret = 0;
+ }
+
+ if (ret) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "could not fstat fd(%s)",
+ uuid_utoa (stub->args.fd->inode->gfid));
+ call_unwind_error (stub, -1, errno);
+ return;
+ }
+
+ call_unwind_error (stub, 0, 0);
+}
+
+
+static void
+posix_fsyncer_syncfs (xlator_t *this, struct list_head *head)
+{
+ call_stub_t *stub = NULL;
+ struct posix_fd *pfd = NULL;
+ int ret = -1;
+
+ stub = list_entry (head->prev, call_stub_t, list);
+ ret = posix_fd_ctx_get (stub->args.fd, this, &pfd);
+ if (ret)
+ return;
+
+#ifdef GF_LINUX_HOST_OS
+ /* syncfs() is not "declared" in RHEL's glibc even though
+ the kernel has support.
+ */
+#include <sys/syscall.h>
+#include <unistd.h>
+ syscall (SYS_syncfs, pfd->fd);
+#else
+ sync();
+#endif
+
+}
+
+
+void *
+posix_fsyncer (void *d)
+{
+ xlator_t *this = d;
+ struct posix_private *priv = NULL;
+ call_stub_t *stub = NULL;
+ call_stub_t *tmp = NULL;
+ struct list_head list;
+ int count = 0;
+ gf_boolean_t do_fsync = _gf_true;
+
+ priv = this->private;
+
+ for (;;) {
+ INIT_LIST_HEAD (&list);
+
+ count = posix_fsyncer_pick (this, &list);
+
+ usleep (priv->batch_fsync_delay_usec);
+
+ gf_log (this->name, GF_LOG_DEBUG,
+ "picked %d fsyncs", count);
+
+ switch (priv->batch_fsync_mode) {
+ case BATCH_NONE:
+ case BATCH_REVERSE_FSYNC:
+ break;
+ case BATCH_SYNCFS:
+ case BATCH_SYNCFS_SINGLE_FSYNC:
+ case BATCH_SYNCFS_REVERSE_FSYNC:
+ posix_fsyncer_syncfs (this, &list);
+ break;
+ }
+
+ if (priv->batch_fsync_mode == BATCH_SYNCFS)
+ do_fsync = _gf_false;
+ else
+ do_fsync = _gf_true;
+
+ list_for_each_entry_safe_reverse (stub, tmp, &list, list) {
+ list_del_init (&stub->list);
+
+ posix_fsyncer_process (this, stub, do_fsync);
+
+ if (priv->batch_fsync_mode == BATCH_SYNCFS_SINGLE_FSYNC)
+ do_fsync = _gf_false;
+ }
+ }
+}
diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index fee2ce9..e917766 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -2417,6 +2417,33 @@ out:
}
+int
+posix_batch_fsync (call_frame_t *frame, xlator_t *this,
+ fd_t *fd, int datasync, dict_t *xdata)
+{
+ call_stub_t *stub = NULL;
+ struct posix_private *priv = NULL;
+
+ priv = this->private;
+
+ stub = fop_fsync_stub (frame, default_fsync, fd, datasync, xdata);
+ if (!stub) {
+ STACK_UNWIND_STRICT (fsync, frame, -1, ENOMEM, 0, 0, 0);
+ return 0;
+ }
+
+ pthread_mutex_lock (&priv->fsync_mutex);
+ {
+ list_add_tail (&stub->list, &priv->fsyncs);
+ priv->fsync_queue_count++;
+ pthread_cond_signal (&priv->fsync_cond);
+ }
+ pthread_mutex_unlock (&priv->fsync_mutex);
+
+ return 0;
+}
+
+
int32_t
posix_fsync (call_frame_t *frame, xlator_t *this,
fd_t *fd, int32_t datasync, dict_t *xdata)
@@ -2428,6 +2455,7 @@ posix_fsync (call_frame_t *frame, xlator_t *this,
int ret = -1;
struct iatt preop = {0,};
struct iatt postop = {0,};
+ struct posix_private *priv = NULL;
DECLARE_OLD_FS_ID_VAR;
@@ -2443,6 +2471,12 @@ posix_fsync (call_frame_t *frame, xlator_t *this,
goto out;
#endif
+ priv = this->private;
+ if (priv->batch_fsync_mode && xdata && dict_get (xdata, "batch-fsync")) {
+ posix_batch_fsync (frame, this, fd, datasync, xdata);
+ return 0;
+ }
+
ret = posix_fd_ctx_get (fd, this, &pfd);
if (ret < 0) {
op_errno = -ret;
@@ -4303,6 +4337,27 @@ posix_set_owner (xlator_t *this, uid_t uid, gid_t gid)
return ret;
}
+
+static int
+set_batch_fsync_mode (struct posix_private *priv, const char *str)
+{
+ if (strcmp (str, "none") == 0)
+ priv->batch_fsync_mode = BATCH_NONE;
+ else if (strcmp (str, "syncfs") == 0)
+ priv->batch_fsync_mode = BATCH_SYNCFS;
+ else if (strcmp (str, "syncfs-single-fsync") == 0)
+ priv->batch_fsync_mode = BATCH_SYNCFS_SINGLE_FSYNC;
+ else if (strcmp (str, "syncfs-reverse-fsync") == 0)
+ priv->batch_fsync_mode = BATCH_SYNCFS_REVERSE_FSYNC;
+ else if (strcmp (str, "reverse-fsync") == 0)
+ priv->batch_fsync_mode = BATCH_REVERSE_FSYNC;
+ else
+ return -1;
+
+ return 0;
+}
+
+
int
reconfigure (xlator_t *this, dict_t *options)
{
@@ -4310,6 +4365,7 @@ reconfigure (xlator_t *this, dict_t *options)
struct posix_private *priv = NULL;
uid_t uid = -1;
gid_t gid = -1;
+ char *batch_fsync_mode_str = NULL;
priv = this->private;
@@ -4317,6 +4373,18 @@ reconfigure (xlator_t *this, dict_t *options)
GF_OPTION_RECONF ("brick-gid", gid, options, uint32, out);
posix_set_owner (this, uid, gid);
+ GF_OPTION_RECONF ("batch-fsync-delay-usec", priv->batch_fsync_delay_usec,
+ options, uint32, out);
+
+ GF_OPTION_RECONF ("batch-fsync-mode", batch_fsync_mode_str,
+ options, str, out);
+
+ if (set_batch_fsync_mode (priv, batch_fsync_mode_str) != 0) {
+ gf_log (this->name, GF_LOG_ERROR, "Unknown mode string: %s",
+ batch_fsync_mode_str);
+ goto out;
+ }
+
GF_OPTION_RECONF ("linux-aio", priv->aio_configured,
options, bool, out);
@@ -4368,6 +4436,7 @@ init (xlator_t *this)
char *guuid = NULL;
uid_t uid = -1;
gid_t gid = -1;
+ char *batch_fsync_mode_str;
dir_data = dict_get (this->options, "directory");
@@ -4720,6 +4789,28 @@ init (xlator_t *this)
INIT_LIST_HEAD (&_private->janitor_fds);
posix_spawn_janitor_thread (this);
+
+ pthread_mutex_init (&_private->fsync_mutex, NULL);
+ pthread_cond_init (&_private->fsync_cond, NULL);
+ INIT_LIST_HEAD (&_private->fsyncs);
+
+ ret = pthread_create (&_private->fsyncer, NULL, posix_fsyncer, this);
+ if (ret) {
+ gf_log (this->name, GF_LOG_ERROR, "fsyncer thread"
+ " creation failed (%s)", strerror (errno));
+ goto out;
+ }
+
+ GF_OPTION_INIT ("batch-fsync-mode", batch_fsync_mode_str, str, out);
+
+ if (set_batch_fsync_mode (_private, batch_fsync_mode_str) != 0) {
+ gf_log (this->name, GF_LOG_ERROR, "Unknown mode string: %s",
+ batch_fsync_mode_str);
+ goto out;
+ }
+
+ GF_OPTION_INIT ("batch-fsync-delay-usec", _private->batch_fsync_delay_usec,
+ uint32, out);
out:
return ret;
}
@@ -4849,5 +4940,25 @@ struct volume_options options[] = {
.description = "Interval in seconds for a filesystem health check, "
"set to 0 to disable"
},
+ { .key = {"batch-fsync-mode"},
+ .type = GF_OPTION_TYPE_STR,
+ .default_value = "reverse-fsync",
+ .description = "Possible values:\n"
+ "\t- syncfs: Perform one syncfs() on behalf oa batch"
+ "of fsyncs.\n"
+ "\t- syncfs-single-fsync: Perform one syncfs() on behalf of a batch"
+ " of fsyncs and one fsync() per batch.\n"
+ "\t- syncfs-reverse-fsync: Preform one syncfs() on behalf of a batch"
+ " of fsyncs and fsync() each file in the batch in reverse order.\n"
+ " in reverse order.\n"
+ "\t- reverse-fsync: Perform fsync() of each file in the batch in"
+ " reverse order."
+ },
+ { .key = {"batch-fsync-delay-usec"},
+ .type = GF_OPTION_TYPE_INT,
+ .default_value = "1000000",
+ .description = "Num of usecs to wait for aggregating fsync"
+ " requests",
+ },
{ .key = {NULL} }
};
diff --git a/xlators/storage/posix/src/posix.h b/xlators/storage/posix/src/posix.h
index 2234037..c834b29 100644
--- a/xlators/storage/posix/src/posix.h
+++ b/xlators/storage/posix/src/posix.h
@@ -43,6 +43,7 @@
#include "timer.h"
#include "posix-mem-types.h"
#include "posix-handle.h"
+#include "call-stub.h"
#ifdef HAVE_LIBAIO
#include <libaio.h>
@@ -128,6 +129,22 @@ struct posix_private {
/* node-uuid in pathinfo xattr */
gf_boolean_t node_uuid_pathinfo;
+ pthread_t fsyncer;
+ struct list_head fsyncs;
+ pthread_mutex_t fsync_mutex;
+ pthread_cond_t fsync_cond;
+ int fsync_queue_count;
+
+ enum {
+ BATCH_NONE = 0,
+ BATCH_SYNCFS,
+ BATCH_SYNCFS_SINGLE_FSYNC,
+ BATCH_REVERSE_FSYNC,
+ BATCH_SYNCFS_REVERSE_FSYNC
+ } batch_fsync_mode;
+
+ uint32_t batch_fsync_delay_usec;
+
/* seconds to sleep between health checks */
uint32_t health_check_interval;
pthread_t health_check;
@@ -184,4 +201,6 @@ void
__posix_fd_set_odirect (fd_t *fd, struct posix_fd *pfd, int opflags,
off_t offset, size_t size);
void posix_spawn_health_check_thread (xlator_t *this);
+
+void *posix_fsyncer (void *);
#endif /* _POSIX_H */