unsigned int for_background:1;
unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */
unsigned int auto_free:1; /* free on completion */
- unsigned int single_wait:1;
- unsigned int single_done:1;
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
static inline struct inode *wb_inode(struct list_head *head)
{
- return list_entry(head, struct inode, i_wb_list);
+ return list_entry(head, struct inode, i_io_list);
}
/*
}
/**
- * inode_wb_list_move_locked - move an inode onto a bdi_writeback IO list
+ * inode_io_list_move_locked - move an inode onto a bdi_writeback IO list
* @inode: inode to be moved
* @wb: target bdi_writeback
* @head: one of @wb->b_{dirty|io|more_io}
*
- * Move @inode->i_wb_list to @list of @wb and set %WB_has_dirty_io.
+ * Move @inode->i_io_list to @list of @wb and set %WB_has_dirty_io.
* Returns %true if @inode is the first occupant of the !dirty_time IO
* lists; otherwise, %false.
*/
-static bool inode_wb_list_move_locked(struct inode *inode,
+static bool inode_io_list_move_locked(struct inode *inode,
struct bdi_writeback *wb,
struct list_head *head)
{
assert_spin_locked(&wb->list_lock);
- list_move(&inode->i_wb_list, head);
+ list_move(&inode->i_io_list, head);
/* dirty_time doesn't count as dirty_io until expiration */
if (head != &wb->b_dirty_time)
}
/**
- * inode_wb_list_del_locked - remove an inode from its bdi_writeback IO list
+ * inode_io_list_del_locked - remove an inode from its bdi_writeback IO list
* @inode: inode to be removed
* @wb: bdi_writeback @inode is being removed from
*
* Remove @inode which may be on one of @wb->b_{dirty|io|more_io} lists and
* clear %WB_has_dirty_io if all are empty afterwards.
*/
-static void inode_wb_list_del_locked(struct inode *inode,
+static void inode_io_list_del_locked(struct inode *inode,
struct bdi_writeback *wb)
{
assert_spin_locked(&wb->list_lock);
- list_del_init(&inode->i_wb_list);
+ list_del_init(&inode->i_io_list);
wb_io_lists_depopulated(wb);
}
static void wb_queue_work(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
- trace_writeback_queue(wb->bdi, work);
+ trace_writeback_queue(wb, work);
spin_lock_bh(&wb->work_lock);
- if (!test_bit(WB_registered, &wb->state)) {
- if (work->single_wait)
- work->single_done = 1;
+ if (!test_bit(WB_registered, &wb->state))
goto out_unlock;
- }
if (work->done)
atomic_inc(&work->done->cnt);
list_add_tail(&work->list, &wb->work_list);
/*
* Once I_FREEING is visible under i_lock, the eviction path owns
- * the inode and we shouldn't modify ->i_wb_list.
+ * the inode and we shouldn't modify ->i_io_list.
*/
if (unlikely(inode->i_state & I_FREEING))
goto skip_switch;
* is always correct including from ->b_dirty_time. The transfer
* preserves @inode->dirtied_when ordering.
*/
- if (!list_empty(&inode->i_wb_list)) {
+ if (!list_empty(&inode->i_io_list)) {
struct inode *pos;
- inode_wb_list_del_locked(inode, old_wb);
+ inode_io_list_del_locked(inode, old_wb);
inode->i_wb = new_wb;
- list_for_each_entry(pos, &new_wb->b_dirty, i_wb_list)
+ list_for_each_entry(pos, &new_wb->b_dirty, i_io_list)
if (time_after_eq(inode->dirtied_when,
pos->dirtied_when))
break;
- inode_wb_list_move_locked(inode, new_wb, pos->i_wb_list.prev);
+ inode_io_list_move_locked(inode, new_wb, pos->i_io_list.prev);
} else {
inode->i_wb = new_wb;
}
/**
* inode_congested - test whether an inode is congested
- * @inode: inode to test for congestion
+ * @inode: inode to test for congestion (may be NULL)
* @cong_bits: mask of WB_[a]sync_congested bits to test
*
* Tests whether @inode is congested. @cong_bits is the mask of congestion
* determined by whether the cgwb (cgroup bdi_writeback) for the blkcg
* associated with @inode is congested; otherwise, the root wb's congestion
* state is used.
+ *
+ * @inode is allowed to be NULL as this function is often called on
+ * mapping->host which is NULL for the swapper space.
*/
int inode_congested(struct inode *inode, int cong_bits)
{
}
EXPORT_SYMBOL_GPL(inode_congested);
-/**
- * wb_wait_for_single_work - wait for completion of a single bdi_writeback_work
- * @bdi: bdi the work item was issued to
- * @work: work item to wait for
- *
- * Wait for the completion of @work which was issued to one of @bdi's
- * bdi_writeback's. The caller must have set @work->single_wait before
- * issuing it. This wait operates independently fo
- * wb_wait_for_completion() and also disables automatic freeing of @work.
- */
-static void wb_wait_for_single_work(struct backing_dev_info *bdi,
- struct wb_writeback_work *work)
-{
- if (WARN_ON_ONCE(!work->single_wait))
- return;
-
- wait_event(bdi->wb_waitq, work->single_done);
-
- /*
- * Paired with smp_wmb() in wb_do_writeback() and ensures that all
- * modifications to @work prior to assertion of ->single_done is
- * visible to the caller once this function returns.
- */
- smp_rmb();
-}
-
/**
* wb_split_bdi_pages - split nr_pages to write according to bandwidth
* @wb: target bdi_writeback to split @nr_pages to
return DIV_ROUND_UP_ULL((u64)nr_pages * this_bw, tot_bw);
}
-/**
- * wb_clone_and_queue_work - clone a wb_writeback_work and issue it to a wb
- * @wb: target bdi_writeback
- * @base_work: source wb_writeback_work
- *
- * Try to make a clone of @base_work and issue it to @wb. If cloning
- * succeeds, %true is returned; otherwise, @base_work is issued directly
- * and %false is returned. In the latter case, the caller is required to
- * wait for @base_work's completion using wb_wait_for_single_work().
- *
- * A clone is auto-freed on completion. @base_work never is.
- */
-static bool wb_clone_and_queue_work(struct bdi_writeback *wb,
- struct wb_writeback_work *base_work)
-{
- struct wb_writeback_work *work;
-
- work = kmalloc(sizeof(*work), GFP_ATOMIC);
- if (work) {
- *work = *base_work;
- work->auto_free = 1;
- work->single_wait = 0;
- } else {
- work = base_work;
- work->auto_free = 0;
- work->single_wait = 1;
- }
- work->single_done = 0;
- wb_queue_work(wb, work);
- return work != base_work;
-}
-
/**
* bdi_split_work_to_wbs - split a wb_writeback_work to all wb's of a bdi
* @bdi: target backing_dev_info
struct wb_writeback_work *base_work,
bool skip_if_busy)
{
- long nr_pages = base_work->nr_pages;
- int next_blkcg_id = 0;
+ int next_memcg_id = 0;
struct bdi_writeback *wb;
struct wb_iter iter;
might_sleep();
restart:
rcu_read_lock();
- bdi_for_each_wb(wb, bdi, &iter, next_blkcg_id) {
+ bdi_for_each_wb(wb, bdi, &iter, next_memcg_id) {
+ DEFINE_WB_COMPLETION_ONSTACK(fallback_work_done);
+ struct wb_writeback_work fallback_work;
+ struct wb_writeback_work *work;
+ long nr_pages;
+
/* SYNC_ALL writes out I_DIRTY_TIME too */
if (!wb_has_dirty_io(wb) &&
(base_work->sync_mode == WB_SYNC_NONE ||
if (skip_if_busy && writeback_in_progress(wb))
continue;
- base_work->nr_pages = wb_split_bdi_pages(wb, nr_pages);
- if (!wb_clone_and_queue_work(wb, base_work)) {
- next_blkcg_id = wb->blkcg_css->id + 1;
- rcu_read_unlock();
- wb_wait_for_single_work(bdi, base_work);
- goto restart;
+ nr_pages = wb_split_bdi_pages(wb, base_work->nr_pages);
+
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ if (work) {
+ *work = *base_work;
+ work->nr_pages = nr_pages;
+ work->auto_free = 1;
+ wb_queue_work(wb, work);
+ continue;
}
+
+ /* alloc failed, execute synchronously using on-stack fallback */
+ work = &fallback_work;
+ *work = *base_work;
+ work->nr_pages = nr_pages;
+ work->auto_free = 0;
+ work->done = &fallback_work_done;
+
+ wb_queue_work(wb, work);
+
+ next_memcg_id = wb->memcg_css->id + 1;
+ rcu_read_unlock();
+ wb_wait_for_completion(bdi, &fallback_work_done);
+ goto restart;
}
rcu_read_unlock();
}
if (!skip_if_busy || !writeback_in_progress(&bdi->wb)) {
base_work->auto_free = 0;
- base_work->single_wait = 0;
- base_work->single_done = 0;
wb_queue_work(&bdi->wb, base_work);
}
}
*/
work = kzalloc(sizeof(*work), GFP_ATOMIC);
if (!work) {
- trace_writeback_nowork(wb->bdi);
+ trace_writeback_nowork(wb);
wb_wakeup(wb);
return;
}
* We just wake up the flusher thread. It will perform background
* writeback as soon as there is no other work to do.
*/
- trace_writeback_wake_background(wb->bdi);
+ trace_writeback_wake_background(wb);
wb_wakeup(wb);
}
/*
* Remove the inode from the writeback list it is on.
*/
-void inode_wb_list_del(struct inode *inode)
+void inode_io_list_del(struct inode *inode)
{
struct bdi_writeback *wb;
wb = inode_to_wb_and_lock_list(inode);
- inode_wb_list_del_locked(inode, wb);
+ inode_io_list_del_locked(inode, wb);
spin_unlock(&wb->list_lock);
}
if (time_before(inode->dirtied_when, tail->dirtied_when))
inode->dirtied_when = jiffies;
}
- inode_wb_list_move_locked(inode, wb, &wb->b_dirty);
+ inode_io_list_move_locked(inode, wb, &wb->b_dirty);
}
/*
*/
static void requeue_io(struct inode *inode, struct bdi_writeback *wb)
{
- inode_wb_list_move_locked(inode, wb, &wb->b_more_io);
+ inode_io_list_move_locked(inode, wb, &wb->b_more_io);
}
static void inode_sync_complete(struct inode *inode)
if (older_than_this &&
inode_dirtied_after(inode, *older_than_this))
break;
- list_move(&inode->i_wb_list, &tmp);
+ list_move(&inode->i_io_list, &tmp);
moved++;
if (flags & EXPIRE_DIRTY_ATIME)
set_bit(__I_DIRTY_TIME_EXPIRED, &inode->i_state);
list_for_each_prev_safe(pos, node, &tmp) {
inode = wb_inode(pos);
if (inode->i_sb == sb)
- list_move(&inode->i_wb_list, dispatch_queue);
+ list_move(&inode->i_io_list, dispatch_queue);
}
}
out:
redirty_tail(inode, wb);
} else if (inode->i_state & I_DIRTY_TIME) {
inode->dirtied_when = jiffies;
- inode_wb_list_move_locked(inode, wb, &wb->b_dirty_time);
+ inode_io_list_move_locked(inode, wb, &wb->b_dirty_time);
} else {
/* The inode is clean. Remove from writeback lists. */
- inode_wb_list_del_locked(inode, wb);
+ inode_io_list_del_locked(inode, wb);
}
}
* touch it. See comment above for explanation.
*/
if (!(inode->i_state & I_DIRTY_ALL))
- inode_wb_list_del_locked(inode, wb);
+ inode_io_list_del_locked(inode, wb);
spin_unlock(&wb->list_lock);
inode_sync_complete(inode);
out:
* Write a portion of b_io inodes which belong to @sb.
*
* Return the number of pages and/or inodes written.
+ *
+ * NOTE! This is called with wb->list_lock held, and will
+ * unlock and relock that for each inode it ends up doing
+ * IO for.
*/
static long writeback_sb_inodes(struct super_block *sb,
struct bdi_writeback *wb,
.range_cyclic = 1,
.reason = reason,
};
+ struct blk_plug plug;
+ blk_start_plug(&plug);
spin_lock(&wb->list_lock);
if (list_empty(&wb->b_io))
queue_io(wb, &work);
__writeback_inodes_wb(wb, &work);
spin_unlock(&wb->list_lock);
+ blk_finish_plug(&plug);
return nr_pages - work.nr_pages;
}
unsigned long oldest_jif;
struct inode *inode;
long progress;
+ struct blk_plug plug;
oldest_jif = jiffies;
work->older_than_this = &oldest_jif;
+ blk_start_plug(&plug);
spin_lock(&wb->list_lock);
for (;;) {
/*
} else if (work->for_background)
oldest_jif = jiffies;
- trace_writeback_start(wb->bdi, work);
+ trace_writeback_start(wb, work);
if (list_empty(&wb->b_io))
queue_io(wb, work);
if (work->sb)
progress = writeback_sb_inodes(work->sb, wb, work);
else
progress = __writeback_inodes_wb(wb, work);
- trace_writeback_written(wb->bdi, work);
+ trace_writeback_written(wb, work);
wb_update_bandwidth(wb, wb_start);
* we'll just busyloop.
*/
if (!list_empty(&wb->b_more_io)) {
- trace_writeback_wait(wb->bdi, work);
+ trace_writeback_wait(wb, work);
inode = wb_inode(wb->b_more_io.prev);
spin_lock(&inode->i_lock);
spin_unlock(&wb->list_lock);
}
}
spin_unlock(&wb->list_lock);
+ blk_finish_plug(&plug);
return nr_pages - work->nr_pages;
}
set_bit(WB_writeback_running, &wb->state);
while ((work = get_next_work_item(wb)) != NULL) {
struct wb_completion *done = work->done;
- bool need_wake_up = false;
- trace_writeback_exec(wb->bdi, work);
+ trace_writeback_exec(wb, work);
wrote += wb_writeback(wb, work);
- if (work->single_wait) {
- WARN_ON_ONCE(work->auto_free);
- /* paired w/ rmb in wb_wait_for_single_work() */
- smp_wmb();
- work->single_done = 1;
- need_wake_up = true;
- } else if (work->auto_free) {
+ if (work->auto_free)
kfree(work);
- }
-
if (done && atomic_dec_and_test(&done->cnt))
- need_wake_up = true;
-
- if (need_wake_up)
wake_up_all(&wb->bdi->wb_waitq);
}
else
dirty_list = &wb->b_dirty_time;
- wakeup_bdi = inode_wb_list_move_locked(inode, wb,
+ wakeup_bdi = inode_io_list_move_locked(inode, wb,
dirty_list);
spin_unlock(&wb->list_lock);
}
EXPORT_SYMBOL(__mark_inode_dirty);
+/*
+ * The @s_sync_lock is used to serialise concurrent sync operations
+ * to avoid lock contention problems with concurrent wait_sb_inodes() calls.
+ * Concurrent callers will block on the s_sync_lock rather than doing contending
+ * walks. The queueing maintains sync(2) required behaviour as all the IO that
+ * has been issued up to the time this function is enter is guaranteed to be
+ * completed by the time we have gained the lock and waited for all IO that is
+ * in progress regardless of the order callers are granted the lock.
+ */
static void wait_sb_inodes(struct super_block *sb)
{
struct inode *inode, *old_inode = NULL;
*/
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- spin_lock(&inode_sb_list_lock);
+ mutex_lock(&sb->s_sync_lock);
+ spin_lock(&sb->s_inode_list_lock);
/*
* Data integrity sync. Must wait for all pages under writeback,
}
__iget(inode);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_sb_list_lock);
+ spin_unlock(&sb->s_inode_list_lock);
/*
* We hold a reference to 'inode' so it couldn't have been
* removed from s_inodes list while we dropped the
- * inode_sb_list_lock. We cannot iput the inode now as we can
+ * s_inode_list_lock. We cannot iput the inode now as we can
* be holding the last reference and we cannot iput it under
- * inode_sb_list_lock. So we keep the reference and iput it
+ * s_inode_list_lock. So we keep the reference and iput it
* later.
*/
iput(old_inode);
cond_resched();
- spin_lock(&inode_sb_list_lock);
+ spin_lock(&sb->s_inode_list_lock);
}
- spin_unlock(&inode_sb_list_lock);
+ spin_unlock(&sb->s_inode_list_lock);
iput(old_inode);
+ mutex_unlock(&sb->s_sync_lock);
}
static void __writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr,
projects / karo-tx-linux.git / blobdiff