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authorLinus Torvalds <torvalds@linux-foundation.org>2010-08-10 15:22:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-10 15:22:42 -0700
commit2f9e825d3e0e2b407ae8f082de5c00afcf7378fb (patch)
treef8b3ee40674ce4acd5508a0a0bf52a30904caf6c /fs/fs-writeback.c
parent7ae0dea900b027cd90e8a3e14deca9a19e17638b (diff)
parentde75d60d5ea235e6e09f4962ab22541ce0fe176a (diff)
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Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block: (149 commits) block: make sure that REQ_* types are seen even with CONFIG_BLOCK=n xen-blkfront: fix missing out label blkdev: fix blkdev_issue_zeroout return value block: update request stacking methods to support discards block: fix missing export of blk_types.h writeback: fix bad _bh spinlock nesting drbd: revert "delay probes", feature is being re-implemented differently drbd: Initialize all members of sync_conf to their defaults [Bugz 315] drbd: Disable delay probes for the upcomming release writeback: cleanup bdi_register writeback: add new tracepoints writeback: remove unnecessary init_timer call writeback: optimize periodic bdi thread wakeups writeback: prevent unnecessary bdi threads wakeups writeback: move bdi threads exiting logic to the forker thread writeback: restructure bdi forker loop a little writeback: move last_active to bdi writeback: do not remove bdi from bdi_list writeback: simplify bdi code a little writeback: do not lose wake-ups in bdi threads ... Fixed up pretty trivial conflicts in drivers/block/virtio_blk.c and drivers/scsi/scsi_error.c as per Jens.
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c161
1 files changed, 104 insertions, 57 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index b7c7586caea..2f76c4a081a 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -26,15 +26,9 @@
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
+#include <linux/tracepoint.h>
#include "internal.h"
-#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
-
-/*
- * We don't actually have pdflush, but this one is exported though /proc...
- */
-int nr_pdflush_threads;
-
/*
* Passed into wb_writeback(), essentially a subset of writeback_control
*/
@@ -50,6 +44,21 @@ struct wb_writeback_work {
struct completion *done; /* set if the caller waits */
};
+/*
+ * Include the creation of the trace points after defining the
+ * wb_writeback_work structure so that the definition remains local to this
+ * file.
+ */
+#define CREATE_TRACE_POINTS
+#include <trace/events/writeback.h>
+
+#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
+
+/*
+ * We don't actually have pdflush, but this one is exported though /proc...
+ */
+int nr_pdflush_threads;
+
/**
* writeback_in_progress - determine whether there is writeback in progress
* @bdi: the device's backing_dev_info structure.
@@ -65,22 +74,21 @@ int writeback_in_progress(struct backing_dev_info *bdi)
static void bdi_queue_work(struct backing_dev_info *bdi,
struct wb_writeback_work *work)
{
- spin_lock(&bdi->wb_lock);
- list_add_tail(&work->list, &bdi->work_list);
- spin_unlock(&bdi->wb_lock);
+ trace_writeback_queue(bdi, work);
- /*
- * If the default thread isn't there, make sure we add it. When
- * it gets created and wakes up, we'll run this work.
- */
- if (unlikely(list_empty_careful(&bdi->wb_list)))
+ spin_lock_bh(&bdi->wb_lock);
+ list_add_tail(&work->list, &bdi->work_list);
+ if (bdi->wb.task) {
+ wake_up_process(bdi->wb.task);
+ } else {
+ /*
+ * The bdi thread isn't there, wake up the forker thread which
+ * will create and run it.
+ */
+ trace_writeback_nothread(bdi, work);
wake_up_process(default_backing_dev_info.wb.task);
- else {
- struct bdi_writeback *wb = &bdi->wb;
-
- if (wb->task)
- wake_up_process(wb->task);
}
+ spin_unlock_bh(&bdi->wb_lock);
}
static void
@@ -95,8 +103,10 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
*/
work = kzalloc(sizeof(*work), GFP_ATOMIC);
if (!work) {
- if (bdi->wb.task)
+ if (bdi->wb.task) {
+ trace_writeback_nowork(bdi);
wake_up_process(bdi->wb.task);
+ }
return;
}
@@ -643,10 +653,14 @@ static long wb_writeback(struct bdi_writeback *wb,
wbc.more_io = 0;
wbc.nr_to_write = MAX_WRITEBACK_PAGES;
wbc.pages_skipped = 0;
+
+ trace_wbc_writeback_start(&wbc, wb->bdi);
if (work->sb)
__writeback_inodes_sb(work->sb, wb, &wbc);
else
writeback_inodes_wb(wb, &wbc);
+ trace_wbc_writeback_written(&wbc, wb->bdi);
+
work->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;
@@ -674,6 +688,7 @@ static long wb_writeback(struct bdi_writeback *wb,
if (!list_empty(&wb->b_more_io)) {
inode = list_entry(wb->b_more_io.prev,
struct inode, i_list);
+ trace_wbc_writeback_wait(&wbc, wb->bdi);
inode_wait_for_writeback(inode);
}
spin_unlock(&inode_lock);
@@ -686,17 +701,17 @@ static long wb_writeback(struct bdi_writeback *wb,
* Return the next wb_writeback_work struct that hasn't been processed yet.
*/
static struct wb_writeback_work *
-get_next_work_item(struct backing_dev_info *bdi, struct bdi_writeback *wb)
+get_next_work_item(struct backing_dev_info *bdi)
{
struct wb_writeback_work *work = NULL;
- spin_lock(&bdi->wb_lock);
+ spin_lock_bh(&bdi->wb_lock);
if (!list_empty(&bdi->work_list)) {
work = list_entry(bdi->work_list.next,
struct wb_writeback_work, list);
list_del_init(&work->list);
}
- spin_unlock(&bdi->wb_lock);
+ spin_unlock_bh(&bdi->wb_lock);
return work;
}
@@ -744,7 +759,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
struct wb_writeback_work *work;
long wrote = 0;
- while ((work = get_next_work_item(bdi, wb)) != NULL) {
+ while ((work = get_next_work_item(bdi)) != NULL) {
/*
* Override sync mode, in case we must wait for completion
* because this thread is exiting now.
@@ -752,6 +767,8 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
if (force_wait)
work->sync_mode = WB_SYNC_ALL;
+ trace_writeback_exec(bdi, work);
+
wrote += wb_writeback(wb, work);
/*
@@ -776,47 +793,66 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
* Handle writeback of dirty data for the device backed by this bdi. Also
* wakes up periodically and does kupdated style flushing.
*/
-int bdi_writeback_task(struct bdi_writeback *wb)
+int bdi_writeback_thread(void *data)
{
- unsigned long last_active = jiffies;
- unsigned long wait_jiffies = -1UL;
+ struct bdi_writeback *wb = data;
+ struct backing_dev_info *bdi = wb->bdi;
long pages_written;
+ current->flags |= PF_FLUSHER | PF_SWAPWRITE;
+ set_freezable();
+ wb->last_active = jiffies;
+
+ /*
+ * Our parent may run at a different priority, just set us to normal
+ */
+ set_user_nice(current, 0);
+
+ trace_writeback_thread_start(bdi);
+
while (!kthread_should_stop()) {
+ /*
+ * Remove own delayed wake-up timer, since we are already awake
+ * and we'll take care of the preriodic write-back.
+ */
+ del_timer(&wb->wakeup_timer);
+
pages_written = wb_do_writeback(wb, 0);
+ trace_writeback_pages_written(pages_written);
+
if (pages_written)
- last_active = jiffies;
- else if (wait_jiffies != -1UL) {
- unsigned long max_idle;
+ wb->last_active = jiffies;
- /*
- * Longest period of inactivity that we tolerate. If we
- * see dirty data again later, the task will get
- * recreated automatically.
- */
- max_idle = max(5UL * 60 * HZ, wait_jiffies);
- if (time_after(jiffies, max_idle + last_active))
- break;
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!list_empty(&bdi->work_list)) {
+ __set_current_state(TASK_RUNNING);
+ continue;
}
- if (dirty_writeback_interval) {
- wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10);
- schedule_timeout_interruptible(wait_jiffies);
- } else {
- set_current_state(TASK_INTERRUPTIBLE);
- if (list_empty_careful(&wb->bdi->work_list) &&
- !kthread_should_stop())
- schedule();
- __set_current_state(TASK_RUNNING);
+ if (wb_has_dirty_io(wb) && dirty_writeback_interval)
+ schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
+ else {
+ /*
+ * We have nothing to do, so can go sleep without any
+ * timeout and save power. When a work is queued or
+ * something is made dirty - we will be woken up.
+ */
+ schedule();
}
try_to_freeze();
}
+ /* Flush any work that raced with us exiting */
+ if (!list_empty(&bdi->work_list))
+ wb_do_writeback(wb, 1);
+
+ trace_writeback_thread_stop(bdi);
return 0;
}
+
/*
* Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back
* the whole world.
@@ -891,6 +927,8 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode)
void __mark_inode_dirty(struct inode *inode, int flags)
{
struct super_block *sb = inode->i_sb;
+ struct backing_dev_info *bdi = NULL;
+ bool wakeup_bdi = false;
/*
* Don't do this for I_DIRTY_PAGES - that doesn't actually
@@ -944,22 +982,31 @@ void __mark_inode_dirty(struct inode *inode, int flags)
* reposition it (that would break b_dirty time-ordering).
*/
if (!was_dirty) {
- struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
- struct backing_dev_info *bdi = wb->bdi;
-
- if (bdi_cap_writeback_dirty(bdi) &&
- !test_bit(BDI_registered, &bdi->state)) {
- WARN_ON(1);
- printk(KERN_ERR "bdi-%s not registered\n",
- bdi->name);
+ bdi = inode_to_bdi(inode);
+
+ if (bdi_cap_writeback_dirty(bdi)) {
+ WARN(!test_bit(BDI_registered, &bdi->state),
+ "bdi-%s not registered\n", bdi->name);
+
+ /*
+ * If this is the first dirty inode for this
+ * bdi, we have to wake-up the corresponding
+ * bdi thread to make sure background
+ * write-back happens later.
+ */
+ if (!wb_has_dirty_io(&bdi->wb))
+ wakeup_bdi = true;
}
inode->dirtied_when = jiffies;
- list_move(&inode->i_list, &wb->b_dirty);
+ list_move(&inode->i_list, &bdi->wb.b_dirty);
}
}
out:
spin_unlock(&inode_lock);
+
+ if (wakeup_bdi)
+ bdi_wakeup_thread_delayed(bdi);
}
EXPORT_SYMBOL(__mark_inode_dirty);