writeback: split inode_wb_list_lock into bdi_writeback.list_lock
Split the global inode_wb_list_lock into a per-bdi_writeback list_lock,
as it's currently the most contended lock in the system for metadata
heavy workloads. It won't help for single-filesystem workloads for
which we'll need the I/O-less balance_dirty_pages, but at least we
can dedicate a cpu to spinning on each bdi now for larger systems.
Based on earlier patches from Nick Piggin and Dave Chinner.
It reduces lock contentions to 1/4 in this test case:
10 HDD JBOD, 100 dd on each disk, XFS, 6GB ram
lock_stat version 0.3
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
vanilla 2.6.39-rc3:
inode_wb_list_lock: 42590 44433 0.12 147.74 144127.35 252274 886792 0.08 121.34 917211.23
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 34 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 12893 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 10702 [<ffffffff8115afef>] writeback_single_inode+0x16d/0x20a
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 19 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 5550 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 8511 [<ffffffff8115b4ad>] writeback_sb_inodes+0x10f/0x157
2.6.39-rc3 + patch:
&(&wb->list_lock)->rlock: 11383 11657 0.14 151.69 40429.51 90825 527918 0.11 145.90 556843.37
------------------------
&(&wb->list_lock)->rlock 10 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 1493 [<ffffffff8115b1ed>] writeback_inodes_wb+0x3d/0x150
&(&wb->list_lock)->rlock 3652 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
&(&wb->list_lock)->rlock 1412 [<ffffffff8115a38e>] writeback_single_inode+0x17f/0x223
------------------------
&(&wb->list_lock)->rlock 3 [<ffffffff8110b5af>] bdi_lock_two+0x46/0x4b
&(&wb->list_lock)->rlock 6 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 2061 [<ffffffff8115af97>] __mark_inode_dirty+0x173/0x1cf
&(&wb->list_lock)->rlock 2629 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
hughd@google.com: fix recursive lock when bdi_lock_two() is called with new the same as old
akpm@linux-foundation.org: cleanup bdev_inode_switch_bdi() comment
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
This commit is contained in:
Christoph Hellwig
committed by
Wu Fengguang
Wu Fengguang
parent
424b351fe1
commit
f758eeabeb
@@ -181,11 +181,12 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi)
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*/
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void inode_wb_list_del(struct inode *inode)
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{
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spin_lock(&inode_wb_list_lock);
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list_del_init(&inode->i_wb_list);
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spin_unlock(&inode_wb_list_lock);
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}
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struct backing_dev_info *bdi = inode_to_bdi(inode);
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spin_lock(&bdi->wb.list_lock);
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list_del_init(&inode->i_wb_list);
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spin_unlock(&bdi->wb.list_lock);
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}
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/*
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* Redirty an inode: set its when-it-was dirtied timestamp and move it to the
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@@ -196,11 +197,9 @@ void inode_wb_list_del(struct inode *inode)
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* the case then the inode must have been redirtied while it was being written
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* out and we don't reset its dirtied_when.
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*/
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static void redirty_tail(struct inode *inode)
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static void redirty_tail(struct inode *inode, struct bdi_writeback *wb)
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{
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struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
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assert_spin_locked(&inode_wb_list_lock);
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assert_spin_locked(&wb->list_lock);
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if (!list_empty(&wb->b_dirty)) {
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struct inode *tail;
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@@ -214,11 +213,9 @@ static void redirty_tail(struct inode *inode)
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/*
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* requeue inode for re-scanning after bdi->b_io list is exhausted.
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*/
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static void requeue_io(struct inode *inode)
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static void requeue_io(struct inode *inode, struct bdi_writeback *wb)
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{
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struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
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assert_spin_locked(&inode_wb_list_lock);
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assert_spin_locked(&wb->list_lock);
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list_move(&inode->i_wb_list, &wb->b_more_io);
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}
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@@ -226,7 +223,7 @@ static void inode_sync_complete(struct inode *inode)
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{
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/*
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* Prevent speculative execution through
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* spin_unlock(&inode_wb_list_lock);
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* spin_unlock(&wb->list_lock);
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*/
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smp_mb();
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@@ -302,7 +299,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
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*/
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static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
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{
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assert_spin_locked(&inode_wb_list_lock);
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assert_spin_locked(&wb->list_lock);
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list_splice_init(&wb->b_more_io, &wb->b_io);
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move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
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}
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@@ -317,7 +314,8 @@ static int write_inode(struct inode *inode, struct writeback_control *wbc)
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/*
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* Wait for writeback on an inode to complete.
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*/
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static void inode_wait_for_writeback(struct inode *inode)
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static void inode_wait_for_writeback(struct inode *inode,
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struct bdi_writeback *wb)
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{
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DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);
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wait_queue_head_t *wqh;
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@@ -325,15 +323,15 @@ static void inode_wait_for_writeback(struct inode *inode)
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wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
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while (inode->i_state & I_SYNC) {
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spin_unlock(&inode->i_lock);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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spin_lock(&inode->i_lock);
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}
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}
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/*
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* Write out an inode's dirty pages. Called under inode_wb_list_lock and
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* Write out an inode's dirty pages. Called under wb->list_lock and
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* inode->i_lock. Either the caller has an active reference on the inode or
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* the inode has I_WILL_FREE set.
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*
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@@ -344,13 +342,14 @@ static void inode_wait_for_writeback(struct inode *inode)
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* livelocks, etc.
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*/
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static int
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writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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writeback_single_inode(struct inode *inode, struct bdi_writeback *wb,
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struct writeback_control *wbc)
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{
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struct address_space *mapping = inode->i_mapping;
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unsigned dirty;
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int ret;
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assert_spin_locked(&inode_wb_list_lock);
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assert_spin_locked(&wb->list_lock);
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assert_spin_locked(&inode->i_lock);
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if (!atomic_read(&inode->i_count))
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@@ -368,14 +367,14 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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* completed a full scan of b_io.
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*/
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if (wbc->sync_mode != WB_SYNC_ALL) {
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requeue_io(inode);
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requeue_io(inode, wb);
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return 0;
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}
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/*
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* It's a data-integrity sync. We must wait.
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*/
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inode_wait_for_writeback(inode);
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inode_wait_for_writeback(inode, wb);
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}
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BUG_ON(inode->i_state & I_SYNC);
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@@ -384,7 +383,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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inode->i_state |= I_SYNC;
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inode->i_state &= ~I_DIRTY_PAGES;
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spin_unlock(&inode->i_lock);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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ret = do_writepages(mapping, wbc);
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@@ -415,7 +414,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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ret = err;
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}
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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spin_lock(&inode->i_lock);
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inode->i_state &= ~I_SYNC;
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if (!(inode->i_state & I_FREEING)) {
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@@ -438,7 +437,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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/*
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* slice used up: queue for next turn
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*/
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requeue_io(inode);
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requeue_io(inode, wb);
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} else {
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/*
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* Writeback blocked by something other than
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@@ -447,7 +446,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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* retrying writeback of the dirty page/inode
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* that cannot be performed immediately.
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*/
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redirty_tail(inode);
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redirty_tail(inode, wb);
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}
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} else if (inode->i_state & I_DIRTY) {
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/*
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@@ -456,7 +455,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
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* submission or metadata updates after data IO
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* completion.
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*/
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redirty_tail(inode);
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redirty_tail(inode, wb);
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} else {
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/*
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* The inode is clean. At this point we either have
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@@ -521,7 +520,7 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
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* superblock, move all inodes not belonging
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* to it back onto the dirty list.
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*/
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redirty_tail(inode);
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redirty_tail(inode, wb);
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continue;
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}
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@@ -541,7 +540,7 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
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spin_lock(&inode->i_lock);
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if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
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spin_unlock(&inode->i_lock);
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requeue_io(inode);
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requeue_io(inode, wb);
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continue;
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}
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@@ -557,19 +556,19 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
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__iget(inode);
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pages_skipped = wbc->pages_skipped;
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writeback_single_inode(inode, wbc);
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writeback_single_inode(inode, wb, wbc);
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if (wbc->pages_skipped != pages_skipped) {
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/*
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* writeback is not making progress due to locked
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* buffers. Skip this inode for now.
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*/
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redirty_tail(inode);
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redirty_tail(inode, wb);
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}
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spin_unlock(&inode->i_lock);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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iput(inode);
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cond_resched();
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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if (wbc->nr_to_write <= 0) {
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wbc->more_io = 1;
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return 1;
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@@ -588,7 +587,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
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if (!wbc->wb_start)
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wbc->wb_start = jiffies; /* livelock avoidance */
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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if (list_empty(&wb->b_io))
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queue_io(wb, wbc->older_than_this);
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@@ -598,7 +597,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
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struct super_block *sb = inode->i_sb;
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if (!pin_sb_for_writeback(sb)) {
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requeue_io(inode);
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requeue_io(inode, wb);
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continue;
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}
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ret = writeback_sb_inodes(sb, wb, wbc, false);
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@@ -607,7 +606,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
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if (ret)
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break;
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}
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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/* Leave any unwritten inodes on b_io */
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}
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@@ -616,11 +615,11 @@ static void __writeback_inodes_sb(struct super_block *sb,
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{
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WARN_ON(!rwsem_is_locked(&sb->s_umount));
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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if (list_empty(&wb->b_io))
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queue_io(wb, wbc->older_than_this);
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writeback_sb_inodes(sb, wb, wbc, true);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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}
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/*
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@@ -762,15 +761,15 @@ static long wb_writeback(struct bdi_writeback *wb,
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* become available for writeback. Otherwise
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* we'll just busyloop.
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*/
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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if (!list_empty(&wb->b_more_io)) {
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inode = wb_inode(wb->b_more_io.prev);
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trace_wbc_writeback_wait(&wbc, wb->bdi);
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spin_lock(&inode->i_lock);
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inode_wait_for_writeback(inode);
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inode_wait_for_writeback(inode, wb);
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spin_unlock(&inode->i_lock);
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}
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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}
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return wrote;
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@@ -1104,10 +1103,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
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}
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spin_unlock(&inode->i_lock);
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spin_lock(&inode_wb_list_lock);
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spin_lock(&bdi->wb.list_lock);
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inode->dirtied_when = jiffies;
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list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&bdi->wb.list_lock);
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if (wakeup_bdi)
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bdi_wakeup_thread_delayed(bdi);
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@@ -1309,6 +1308,7 @@ EXPORT_SYMBOL(sync_inodes_sb);
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*/
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int write_inode_now(struct inode *inode, int sync)
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{
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struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
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int ret;
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struct writeback_control wbc = {
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.nr_to_write = LONG_MAX,
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@@ -1321,11 +1321,11 @@ int write_inode_now(struct inode *inode, int sync)
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wbc.nr_to_write = 0;
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might_sleep();
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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spin_lock(&inode->i_lock);
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ret = writeback_single_inode(inode, &wbc);
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ret = writeback_single_inode(inode, wb, &wbc);
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spin_unlock(&inode->i_lock);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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if (sync)
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inode_sync_wait(inode);
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return ret;
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@@ -1345,13 +1345,14 @@ EXPORT_SYMBOL(write_inode_now);
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*/
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int sync_inode(struct inode *inode, struct writeback_control *wbc)
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{
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struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
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int ret;
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spin_lock(&inode_wb_list_lock);
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spin_lock(&wb->list_lock);
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spin_lock(&inode->i_lock);
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ret = writeback_single_inode(inode, wbc);
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ret = writeback_single_inode(inode, wb, wbc);
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spin_unlock(&inode->i_lock);
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spin_unlock(&inode_wb_list_lock);
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spin_unlock(&wb->list_lock);
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return ret;
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}
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EXPORT_SYMBOL(sync_inode);
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Reference in New Issue
Block a user