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linux/include/trace/events/writeback.h
Jan Kara c4a391b53a writeback: do not sync data dirtied after sync start 
When there are processes heavily creating small files while sync(2) is
running, it can easily happen that quite some new files are created
between WB_SYNC_NONE and WB_SYNC_ALL pass of sync(2).  That can happen
especially if there are several busy filesystems (remember that sync
traverses filesystems sequentially and waits in WB_SYNC_ALL phase on one
fs before starting it on another fs).  Because WB_SYNC_ALL pass is slow
(e.g.  causes a transaction commit and cache flush for each inode in
ext3), resulting sync(2) times are rather large.

The following script reproduces the problem:

  function run_writers
  {
    for (( i = 0; i < 10; i++ )); do
      mkdir $1/dir$i
      for (( j = 0; j < 40000; j++ )); do
        dd if=/dev/zero of=$1/dir$i/$j bs=4k count=4 &>/dev/null
      done &
    done
  }

  for dir in "$@"; do
    run_writers $dir
  done

  sleep 40
  time sync

Fix the problem by disregarding inodes dirtied after sync(2) was called
in the WB_SYNC_ALL pass.  To allow for this, sync_inodes_sb() now takes
a time stamp when sync has started which is used for setting up work for
flusher threads.

To give some numbers, when above script is run on two ext4 filesystems
on simple SATA drive, the average sync time from 10 runs is 267.549
seconds with standard deviation 104.799426.  With the patched kernel,
the average sync time from 10 runs is 2.995 seconds with standard
deviation 0.096.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:07 +09:00

604 lines
16 KiB
C
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#undef TRACE_SYSTEM
#define TRACE_SYSTEM writeback
#if !defined(_TRACE_WRITEBACK_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_WRITEBACK_H
#include <linux/backing-dev.h>
#include <linux/writeback.h>
#define show_inode_state(state) \
__print_flags(state, "|", \
{I_DIRTY_SYNC, "I_DIRTY_SYNC"}, \
{I_DIRTY_DATASYNC, "I_DIRTY_DATASYNC"}, \
{I_DIRTY_PAGES, "I_DIRTY_PAGES"}, \
{I_NEW, "I_NEW"}, \
{I_WILL_FREE, "I_WILL_FREE"}, \
{I_FREEING, "I_FREEING"}, \
{I_CLEAR, "I_CLEAR"}, \
{I_SYNC, "I_SYNC"}, \
{I_REFERENCED, "I_REFERENCED"} \
)
#define WB_WORK_REASON \
{WB_REASON_BACKGROUND, "background"}, \
{WB_REASON_TRY_TO_FREE_PAGES, "try_to_free_pages"}, \
{WB_REASON_SYNC, "sync"}, \
{WB_REASON_PERIODIC, "periodic"}, \
{WB_REASON_LAPTOP_TIMER, "laptop_timer"}, \
{WB_REASON_FREE_MORE_MEM, "free_more_memory"}, \
{WB_REASON_FS_FREE_SPACE, "fs_free_space"}, \
{WB_REASON_FORKER_THREAD, "forker_thread"}
struct wb_writeback_work;
TRACE_EVENT(writeback_dirty_page,
TP_PROTO(struct page *page, struct address_space *mapping),
TP_ARGS(page, mapping),
TP_STRUCT__entry (
__array(char, name, 32)
__field(unsigned long, ino)
__field(pgoff_t, index)
),
TP_fast_assign(
strncpy(__entry->name,
mapping ? dev_name(mapping->backing_dev_info->dev) : "(unknown)", 32);
__entry->ino = mapping ? mapping->host->i_ino : 0;
__entry->index = page->index;
),
TP_printk("bdi %s: ino=%lu index=%lu",
__entry->name,
__entry->ino,
__entry->index
)
);
DECLARE_EVENT_CLASS(writeback_dirty_inode_template,
TP_PROTO(struct inode *inode, int flags),
TP_ARGS(inode, flags),
TP_STRUCT__entry (
__array(char, name, 32)
__field(unsigned long, ino)
__field(unsigned long, flags)
),
TP_fast_assign(
struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
/* may be called for files on pseudo FSes w/ unregistered bdi */
strncpy(__entry->name,
bdi->dev ? dev_name(bdi->dev) : "(unknown)", 32);
__entry->ino = inode->i_ino;
__entry->flags = flags;
),
TP_printk("bdi %s: ino=%lu flags=%s",
__entry->name,
__entry->ino,
show_inode_state(__entry->flags)
)
);
DEFINE_EVENT(writeback_dirty_inode_template, writeback_dirty_inode_start,
TP_PROTO(struct inode *inode, int flags),
TP_ARGS(inode, flags)
);
DEFINE_EVENT(writeback_dirty_inode_template, writeback_dirty_inode,
TP_PROTO(struct inode *inode, int flags),
TP_ARGS(inode, flags)
);
DECLARE_EVENT_CLASS(writeback_write_inode_template,
TP_PROTO(struct inode *inode, struct writeback_control *wbc),
TP_ARGS(inode, wbc),
TP_STRUCT__entry (
__array(char, name, 32)
__field(unsigned long, ino)
__field(int, sync_mode)
),
TP_fast_assign(
strncpy(__entry->name,
dev_name(inode->i_mapping->backing_dev_info->dev), 32);
__entry->ino = inode->i_ino;
__entry->sync_mode = wbc->sync_mode;
),
TP_printk("bdi %s: ino=%lu sync_mode=%d",
__entry->name,
__entry->ino,
__entry->sync_mode
)
);
DEFINE_EVENT(writeback_write_inode_template, writeback_write_inode_start,
TP_PROTO(struct inode *inode, struct writeback_control *wbc),
TP_ARGS(inode, wbc)
);
DEFINE_EVENT(writeback_write_inode_template, writeback_write_inode,
TP_PROTO(struct inode *inode, struct writeback_control *wbc),
TP_ARGS(inode, wbc)
);
DECLARE_EVENT_CLASS(writeback_work_class,
TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work),
TP_ARGS(bdi, work),
TP_STRUCT__entry(
__array(char, name, 32)
__field(long, nr_pages)
__field(dev_t, sb_dev)
__field(int, sync_mode)
__field(int, for_kupdate)
__field(int, range_cyclic)
__field(int, for_background)
__field(int, reason)
),
TP_fast_assign(
struct device *dev = bdi->dev;
if (!dev)
dev = default_backing_dev_info.dev;
strncpy(__entry->name, dev_name(dev), 32);
__entry->nr_pages = work->nr_pages;
__entry->sb_dev = work->sb ? work->sb->s_dev : 0;
__entry->sync_mode = work->sync_mode;
__entry->for_kupdate = work->for_kupdate;
__entry->range_cyclic = work->range_cyclic;
__entry->for_background = work->for_background;
__entry->reason = work->reason;
),
TP_printk("bdi %s: sb_dev %d:%d nr_pages=%ld sync_mode=%d "
"kupdate=%d range_cyclic=%d background=%d reason=%s",
__entry->name,
MAJOR(__entry->sb_dev), MINOR(__entry->sb_dev),
__entry->nr_pages,
__entry->sync_mode,
__entry->for_kupdate,
__entry->range_cyclic,
__entry->for_background,
__print_symbolic(__entry->reason, WB_WORK_REASON)
)
);
#define DEFINE_WRITEBACK_WORK_EVENT(name) \
DEFINE_EVENT(writeback_work_class, name, \
TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work), \
TP_ARGS(bdi, work))
DEFINE_WRITEBACK_WORK_EVENT(writeback_queue);
DEFINE_WRITEBACK_WORK_EVENT(writeback_exec);
DEFINE_WRITEBACK_WORK_EVENT(writeback_start);
DEFINE_WRITEBACK_WORK_EVENT(writeback_written);
DEFINE_WRITEBACK_WORK_EVENT(writeback_wait);
TRACE_EVENT(writeback_pages_written,
TP_PROTO(long pages_written),
TP_ARGS(pages_written),
TP_STRUCT__entry(
__field(long, pages)
),
TP_fast_assign(
__entry->pages = pages_written;
),
TP_printk("%ld", __entry->pages)
);
DECLARE_EVENT_CLASS(writeback_class,
TP_PROTO(struct backing_dev_info *bdi),
TP_ARGS(bdi),
TP_STRUCT__entry(
__array(char, name, 32)
),
TP_fast_assign(
strncpy(__entry->name, dev_name(bdi->dev), 32);
),
TP_printk("bdi %s",
__entry->name
)
);
#define DEFINE_WRITEBACK_EVENT(name) \
DEFINE_EVENT(writeback_class, name, \
TP_PROTO(struct backing_dev_info *bdi), \
TP_ARGS(bdi))
DEFINE_WRITEBACK_EVENT(writeback_nowork);
DEFINE_WRITEBACK_EVENT(writeback_wake_background);
DEFINE_WRITEBACK_EVENT(writeback_bdi_register);
DEFINE_WRITEBACK_EVENT(writeback_bdi_unregister);
DECLARE_EVENT_CLASS(wbc_class,
TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi),
TP_ARGS(wbc, bdi),
TP_STRUCT__entry(
__array(char, name, 32)
__field(long, nr_to_write)
__field(long, pages_skipped)
__field(int, sync_mode)
__field(int, for_kupdate)
__field(int, for_background)
__field(int, for_reclaim)
__field(int, range_cyclic)
__field(long, range_start)
__field(long, range_end)
),
TP_fast_assign(
strncpy(__entry->name, dev_name(bdi->dev), 32);
__entry->nr_to_write = wbc->nr_to_write;
__entry->pages_skipped = wbc->pages_skipped;
__entry->sync_mode = wbc->sync_mode;
__entry->for_kupdate = wbc->for_kupdate;
__entry->for_background = wbc->for_background;
__entry->for_reclaim = wbc->for_reclaim;
__entry->range_cyclic = wbc->range_cyclic;
__entry->range_start = (long)wbc->range_start;
__entry->range_end = (long)wbc->range_end;
),
TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d "
"bgrd=%d reclm=%d cyclic=%d "
"start=0x%lx end=0x%lx",
__entry->name,
__entry->nr_to_write,
__entry->pages_skipped,
__entry->sync_mode,
__entry->for_kupdate,
__entry->for_background,
__entry->for_reclaim,
__entry->range_cyclic,
__entry->range_start,
__entry->range_end)
)
#define DEFINE_WBC_EVENT(name) \
DEFINE_EVENT(wbc_class, name, \
TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi), \
TP_ARGS(wbc, bdi))
DEFINE_WBC_EVENT(wbc_writepage);
TRACE_EVENT(writeback_queue_io,
TP_PROTO(struct bdi_writeback *wb,
struct wb_writeback_work *work,
int moved),
TP_ARGS(wb, work, moved),
TP_STRUCT__entry(
__array(char, name, 32)
__field(unsigned long, older)
__field(long, age)
__field(int, moved)
__field(int, reason)
),
TP_fast_assign(
unsigned long older_than_this = work->older_than_this;
strncpy(__entry->name, dev_name(wb->bdi->dev), 32);
__entry->older = older_than_this;
__entry->age = older_than_this ?
(jiffies - older_than_this) * 1000 / HZ : -1;
__entry->moved = moved;
__entry->reason = work->reason;
),
TP_printk("bdi %s: older=%lu age=%ld enqueue=%d reason=%s",
__entry->name,
__entry->older, /* older_than_this in jiffies */
__entry->age, /* older_than_this in relative milliseconds */
__entry->moved,
__print_symbolic(__entry->reason, WB_WORK_REASON)
)
);
TRACE_EVENT(global_dirty_state,
TP_PROTO(unsigned long background_thresh,
unsigned long dirty_thresh
),
TP_ARGS(background_thresh,
dirty_thresh
),
TP_STRUCT__entry(
__field(unsigned long, nr_dirty)
__field(unsigned long, nr_writeback)
__field(unsigned long, nr_unstable)
__field(unsigned long, background_thresh)
__field(unsigned long, dirty_thresh)
__field(unsigned long, dirty_limit)
__field(unsigned long, nr_dirtied)
__field(unsigned long, nr_written)
),
TP_fast_assign(
__entry->nr_dirty = global_page_state(NR_FILE_DIRTY);
__entry->nr_writeback = global_page_state(NR_WRITEBACK);
__entry->nr_unstable = global_page_state(NR_UNSTABLE_NFS);
__entry->nr_dirtied = global_page_state(NR_DIRTIED);
__entry->nr_written = global_page_state(NR_WRITTEN);
__entry->background_thresh = background_thresh;
__entry->dirty_thresh = dirty_thresh;
__entry->dirty_limit = global_dirty_limit;
),
TP_printk("dirty=%lu writeback=%lu unstable=%lu "
"bg_thresh=%lu thresh=%lu limit=%lu "
"dirtied=%lu written=%lu",
__entry->nr_dirty,
__entry->nr_writeback,
__entry->nr_unstable,
__entry->background_thresh,
__entry->dirty_thresh,
__entry->dirty_limit,
__entry->nr_dirtied,
__entry->nr_written
)
);
#define KBps(x) ((x) << (PAGE_SHIFT - 10))
TRACE_EVENT(bdi_dirty_ratelimit,
TP_PROTO(struct backing_dev_info *bdi,
unsigned long dirty_rate,
unsigned long task_ratelimit),
TP_ARGS(bdi, dirty_rate, task_ratelimit),
TP_STRUCT__entry(
__array(char, bdi, 32)
__field(unsigned long, write_bw)
__field(unsigned long, avg_write_bw)
__field(unsigned long, dirty_rate)
__field(unsigned long, dirty_ratelimit)
__field(unsigned long, task_ratelimit)
__field(unsigned long, balanced_dirty_ratelimit)
),
TP_fast_assign(
strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
__entry->write_bw = KBps(bdi->write_bandwidth);
__entry->avg_write_bw = KBps(bdi->avg_write_bandwidth);
__entry->dirty_rate = KBps(dirty_rate);
__entry->dirty_ratelimit = KBps(bdi->dirty_ratelimit);
__entry->task_ratelimit = KBps(task_ratelimit);
__entry->balanced_dirty_ratelimit =
KBps(bdi->balanced_dirty_ratelimit);
),
TP_printk("bdi %s: "
"write_bw=%lu awrite_bw=%lu dirty_rate=%lu "
"dirty_ratelimit=%lu task_ratelimit=%lu "
"balanced_dirty_ratelimit=%lu",
__entry->bdi,
__entry->write_bw, /* write bandwidth */
__entry->avg_write_bw, /* avg write bandwidth */
__entry->dirty_rate, /* bdi dirty rate */
__entry->dirty_ratelimit, /* base ratelimit */
__entry->task_ratelimit, /* ratelimit with position control */
__entry->balanced_dirty_ratelimit /* the balanced ratelimit */
)
);
TRACE_EVENT(balance_dirty_pages,
TP_PROTO(struct backing_dev_info *bdi,
unsigned long thresh,
unsigned long bg_thresh,
unsigned long dirty,
unsigned long bdi_thresh,
unsigned long bdi_dirty,
unsigned long dirty_ratelimit,
unsigned long task_ratelimit,
unsigned long dirtied,
unsigned long period,
long pause,
unsigned long start_time),
TP_ARGS(bdi, thresh, bg_thresh, dirty, bdi_thresh, bdi_dirty,
dirty_ratelimit, task_ratelimit,
dirtied, period, pause, start_time),
TP_STRUCT__entry(
__array( char, bdi, 32)
__field(unsigned long, limit)
__field(unsigned long, setpoint)
__field(unsigned long, dirty)
__field(unsigned long, bdi_setpoint)
__field(unsigned long, bdi_dirty)
__field(unsigned long, dirty_ratelimit)
__field(unsigned long, task_ratelimit)
__field(unsigned int, dirtied)
__field(unsigned int, dirtied_pause)
__field(unsigned long, paused)
__field( long, pause)
__field(unsigned long, period)
__field( long, think)
),
TP_fast_assign(
unsigned long freerun = (thresh + bg_thresh) / 2;
strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
__entry->limit = global_dirty_limit;
__entry->setpoint = (global_dirty_limit + freerun) / 2;
__entry->dirty = dirty;
__entry->bdi_setpoint = __entry->setpoint *
bdi_thresh / (thresh + 1);
__entry->bdi_dirty = bdi_dirty;
__entry->dirty_ratelimit = KBps(dirty_ratelimit);
__entry->task_ratelimit = KBps(task_ratelimit);
__entry->dirtied = dirtied;
__entry->dirtied_pause = current->nr_dirtied_pause;
__entry->think = current->dirty_paused_when == 0 ? 0 :
(long)(jiffies - current->dirty_paused_when) * 1000/HZ;
__entry->period = period * 1000 / HZ;
__entry->pause = pause * 1000 / HZ;
__entry->paused = (jiffies - start_time) * 1000 / HZ;
),
TP_printk("bdi %s: "
"limit=%lu setpoint=%lu dirty=%lu "
"bdi_setpoint=%lu bdi_dirty=%lu "
"dirty_ratelimit=%lu task_ratelimit=%lu "
"dirtied=%u dirtied_pause=%u "
"paused=%lu pause=%ld period=%lu think=%ld",
__entry->bdi,
__entry->limit,
__entry->setpoint,
__entry->dirty,
__entry->bdi_setpoint,
__entry->bdi_dirty,
__entry->dirty_ratelimit,
__entry->task_ratelimit,
__entry->dirtied,
__entry->dirtied_pause,
__entry->paused, /* ms */
__entry->pause, /* ms */
__entry->period, /* ms */
__entry->think /* ms */
)
);
TRACE_EVENT(writeback_sb_inodes_requeue,
TP_PROTO(struct inode *inode),
TP_ARGS(inode),
TP_STRUCT__entry(
__array(char, name, 32)
__field(unsigned long, ino)
__field(unsigned long, state)
__field(unsigned long, dirtied_when)
),
TP_fast_assign(
strncpy(__entry->name,
dev_name(inode_to_bdi(inode)->dev), 32);
__entry->ino = inode->i_ino;
__entry->state = inode->i_state;
__entry->dirtied_when = inode->dirtied_when;
),
TP_printk("bdi %s: ino=%lu state=%s dirtied_when=%lu age=%lu",
__entry->name,
__entry->ino,
show_inode_state(__entry->state),
__entry->dirtied_when,
(jiffies - __entry->dirtied_when) / HZ
)
);
DECLARE_EVENT_CLASS(writeback_congest_waited_template,
TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
TP_ARGS(usec_timeout, usec_delayed),
TP_STRUCT__entry(
__field( unsigned int, usec_timeout )
__field( unsigned int, usec_delayed )
),
TP_fast_assign(
__entry->usec_timeout = usec_timeout;
__entry->usec_delayed = usec_delayed;
),
TP_printk("usec_timeout=%u usec_delayed=%u",
__entry->usec_timeout,
__entry->usec_delayed)
);
DEFINE_EVENT(writeback_congest_waited_template, writeback_congestion_wait,
TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
TP_ARGS(usec_timeout, usec_delayed)
);
DEFINE_EVENT(writeback_congest_waited_template, writeback_wait_iff_congested,
TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
TP_ARGS(usec_timeout, usec_delayed)
);
DECLARE_EVENT_CLASS(writeback_single_inode_template,
TP_PROTO(struct inode *inode,
struct writeback_control *wbc,
unsigned long nr_to_write
),
TP_ARGS(inode, wbc, nr_to_write),
TP_STRUCT__entry(
__array(char, name, 32)
__field(unsigned long, ino)
__field(unsigned long, state)
__field(unsigned long, dirtied_when)
__field(unsigned long, writeback_index)
__field(long, nr_to_write)
__field(unsigned long, wrote)
),
TP_fast_assign(
strncpy(__entry->name,
dev_name(inode_to_bdi(inode)->dev), 32);
__entry->ino = inode->i_ino;
__entry->state = inode->i_state;
__entry->dirtied_when = inode->dirtied_when;
__entry->writeback_index = inode->i_mapping->writeback_index;
__entry->nr_to_write = nr_to_write;
__entry->wrote = nr_to_write - wbc->nr_to_write;
),
TP_printk("bdi %s: ino=%lu state=%s dirtied_when=%lu age=%lu "
"index=%lu to_write=%ld wrote=%lu",
__entry->name,
__entry->ino,
show_inode_state(__entry->state),
__entry->dirtied_when,
(jiffies - __entry->dirtied_when) / HZ,
__entry->writeback_index,
__entry->nr_to_write,
__entry->wrote
)
);
DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode_start,
TP_PROTO(struct inode *inode,
struct writeback_control *wbc,
unsigned long nr_to_write),
TP_ARGS(inode, wbc, nr_to_write)
);
DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode,
TP_PROTO(struct inode *inode,
struct writeback_control *wbc,
unsigned long nr_to_write),
TP_ARGS(inode, wbc, nr_to_write)
);
#endif /* _TRACE_WRITEBACK_H */
/* This part must be outside protection */
#include <trace/define_trace.h>
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