From 9ba4b2dfafaa711b41cc2102b0e9a529f3981218 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Wed, 20 Sep 2017 08:58:25 -0600
Subject: fs: kill 'nr_pages' argument from wakeup_flusher_threads()
Everybody is passing in 0 now, let's get rid of the argument.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
include/linux/writeback.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'include/linux/writeback.h')
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index d5815794416c..1f9c6db5e29a 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -189,7 +189,7 @@ bool try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
enum wb_reason reason);
void sync_inodes_sb(struct super_block *);
-void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
+void wakeup_flusher_threads(enum wb_reason reason);
void inode_wait_for_writeback(struct inode *inode);
/* writeback.h requires fs.h; it, too, is not included from here. */
--
cgit v1.2.3-70-g09d2
From 595043e5f9ef1d8263bd9fda215cade489227491 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 28 Sep 2017 11:26:59 -0600
Subject: writeback: provide a wakeup_flusher_threads_bdi()
Similar to wakeup_flusher_threads(), except that we only wake
up the flusher threads on the specified backing device.
No functional changes in this patch.
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Chris Mason <clm@fb.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/fs-writeback.c | 39 +++++++++++++++++++++++++++++----------
include/linux/writeback.h | 2 ++
2 files changed, 31 insertions(+), 10 deletions(-)
(limited to 'include/linux/writeback.h')
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index fe555bce886c..9f39829459dc 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1946,6 +1946,33 @@ void wb_workfn(struct work_struct *work)
current->flags &= ~PF_SWAPWRITE;
}
+/*
+ * Start writeback of `nr_pages' pages on this bdi. If `nr_pages' is zero,
+ * write back the whole world.
+ */
+static void __wakeup_flusher_threads_bdi(struct backing_dev_info *bdi,
+ long nr_pages, enum wb_reason reason)
+{
+ struct bdi_writeback *wb;
+
+ if (!bdi_has_dirty_io(bdi))
+ return;
+
+ list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node)
+ wb_start_writeback(wb, wb_split_bdi_pages(wb, nr_pages),
+ reason);
+}
+
+void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi,
+ enum wb_reason reason)
+{
+ long nr_pages = get_nr_dirty_pages();
+
+ rcu_read_lock();
+ __wakeup_flusher_threads_bdi(bdi, nr_pages, reason);
+ rcu_read_unlock();
+}
+
/*
* Wakeup the flusher threads to start writeback of all currently dirty pages
*/
@@ -1963,16 +1990,8 @@ void wakeup_flusher_threads(enum wb_reason reason)
nr_pages = get_nr_dirty_pages();
rcu_read_lock();
- list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
- struct bdi_writeback *wb;
-
- if (!bdi_has_dirty_io(bdi))
- continue;
-
- list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node)
- wb_start_writeback(wb, wb_split_bdi_pages(wb, nr_pages),
- reason);
- }
+ list_for_each_entry_rcu(bdi, &bdi_list, bdi_list)
+ __wakeup_flusher_threads_bdi(bdi, nr_pages, reason);
rcu_read_unlock();
}
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 1f9c6db5e29a..9c0091678af4 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -190,6 +190,8 @@ bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
enum wb_reason reason);
void sync_inodes_sb(struct super_block *);
void wakeup_flusher_threads(enum wb_reason reason);
+void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi,
+ enum wb_reason reason);
void inode_wait_for_writeback(struct inode *inode);
/* writeback.h requires fs.h; it, too, is not included from here. */
--
cgit v1.2.3-70-g09d2
From 85009b4f5f0399669a44f07cb9a5622c0e71d419 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Sat, 30 Sep 2017 02:09:06 -0600
Subject: writeback: eliminate work item allocation in bd_start_writeback()
Handle start-all writeback like we do periodic or kupdate
style writeback - by marking the bdi_writeback as needing a full
flush, and simply waking the thread. This eliminates the need to
allocate and queue a specific work item just for this purpose.
After this change, we truly only ever have one of them running at
any point in time. We mark the need to start all flushes, and the
writeback thread will clear it once it has processed the request.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/fs-writeback.c | 71 +++++++++++++++++++---------------------
include/linux/backing-dev-defs.h | 23 +++++++++++++
include/linux/writeback.h | 22 -------------
include/trace/events/writeback.h | 1 -
4 files changed, 57 insertions(+), 60 deletions(-)
(limited to 'include/linux/writeback.h')
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 399619c97567..9e24d604c59c 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -53,7 +53,6 @@ struct wb_writeback_work {
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 start_all:1; /* nr_pages == 0 (all) writeback */
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
@@ -947,8 +946,6 @@ static unsigned long get_nr_dirty_pages(void)
static void wb_start_writeback(struct bdi_writeback *wb, enum wb_reason reason)
{
- struct wb_writeback_work *work;
-
if (!wb_has_dirty_io(wb))
return;
@@ -958,35 +955,14 @@ static void wb_start_writeback(struct bdi_writeback *wb, enum wb_reason reason)
* high frequency, causing pointless allocations of tons of
* work items and keeping the flusher threads busy retrieving
* that work. Ensure that we only allow one of them pending and
- * inflight at the time. It doesn't matter if we race a little
- * bit on this, so use the faster separate test/set bit variants.
+ * inflight at the time.
*/
- if (test_bit(WB_start_all, &wb->state))
+ if (test_bit(WB_start_all, &wb->state) ||
+ test_and_set_bit(WB_start_all, &wb->state))
return;
- set_bit(WB_start_all, &wb->state);
-
- /*
- * This is WB_SYNC_NONE writeback, so if allocation fails just
- * wakeup the thread for old dirty data writeback
- */
- work = kzalloc(sizeof(*work),
- GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
- if (!work) {
- clear_bit(WB_start_all, &wb->state);
- trace_writeback_nowork(wb);
- wb_wakeup(wb);
- return;
- }
-
- work->sync_mode = WB_SYNC_NONE;
- work->nr_pages = wb_split_bdi_pages(wb, get_nr_dirty_pages());
- work->range_cyclic = 1;
- work->reason = reason;
- work->auto_free = 1;
- work->start_all = 1;
-
- wb_queue_work(wb, work);
+ wb->start_all_reason = reason;
+ wb_wakeup(wb);
}
/**
@@ -1838,14 +1814,6 @@ static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb)
list_del_init(&work->list);
}
spin_unlock_bh(&wb->work_lock);
-
- /*
- * Once we start processing a work item that had !nr_pages,
- * clear the wb state bit for that so we can allow more.
- */
- if (work && work->start_all)
- clear_bit(WB_start_all, &wb->state);
-
return work;
}
@@ -1901,6 +1869,30 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
return 0;
}
+static long wb_check_start_all(struct bdi_writeback *wb)
+{
+ long nr_pages;
+
+ if (!test_bit(WB_start_all, &wb->state))
+ return 0;
+
+ nr_pages = get_nr_dirty_pages();
+ if (nr_pages) {
+ struct wb_writeback_work work = {
+ .nr_pages = wb_split_bdi_pages(wb, nr_pages),
+ .sync_mode = WB_SYNC_NONE,
+ .range_cyclic = 1,
+ .reason = wb->start_all_reason,
+ };
+
+ nr_pages = wb_writeback(wb, &work);
+ }
+
+ clear_bit(WB_start_all, &wb->state);
+ return nr_pages;
+}
+
+
/*
* Retrieve work items and do the writeback they describe
*/
@@ -1916,6 +1908,11 @@ static long wb_do_writeback(struct bdi_writeback *wb)
finish_writeback_work(wb, work);
}
+ /*
+ * Check for a flush-everything request
+ */
+ wrote += wb_check_start_all(wb);
+
/*
* Check for periodic writeback, kupdated() style
*/
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index 420de5c7c7f9..b7c7be6f5986 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -44,6 +44,28 @@ enum wb_stat_item {
#define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
+/*
+ * why some writeback work was initiated
+ */
+enum wb_reason {
+ WB_REASON_BACKGROUND,
+ WB_REASON_VMSCAN,
+ WB_REASON_SYNC,
+ WB_REASON_PERIODIC,
+ WB_REASON_LAPTOP_TIMER,
+ WB_REASON_FREE_MORE_MEM,
+ WB_REASON_FS_FREE_SPACE,
+ /*
+ * There is no bdi forker thread any more and works are done
+ * by emergency worker, however, this is TPs userland visible
+ * and we'll be exposing exactly the same information,
+ * so it has a mismatch name.
+ */
+ WB_REASON_FORKER_THREAD,
+
+ WB_REASON_MAX,
+};
+
/*
* For cgroup writeback, multiple wb's may map to the same blkcg. Those
* wb's can operate mostly independently but should share the congested
@@ -116,6 +138,7 @@ struct bdi_writeback {
struct fprop_local_percpu completions;
int dirty_exceeded;
+ enum wb_reason start_all_reason;
spinlock_t work_lock; /* protects work_list & dwork scheduling */
struct list_head work_list;
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 9c0091678af4..dd1d2c23f743 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -41,28 +41,6 @@ enum writeback_sync_modes {
WB_SYNC_ALL, /* Wait on every mapping */
};
-/*
- * why some writeback work was initiated
- */
-enum wb_reason {
- WB_REASON_BACKGROUND,
- WB_REASON_VMSCAN,
- WB_REASON_SYNC,
- WB_REASON_PERIODIC,
- WB_REASON_LAPTOP_TIMER,
- WB_REASON_FREE_MORE_MEM,
- WB_REASON_FS_FREE_SPACE,
- /*
- * There is no bdi forker thread any more and works are done
- * by emergency worker, however, this is TPs userland visible
- * and we'll be exposing exactly the same information,
- * so it has a mismatch name.
- */
- WB_REASON_FORKER_THREAD,
-
- WB_REASON_MAX,
-};
-
/*
* A control structure which tells the writeback code what to do. These are
* always on the stack, and hence need no locking. They are always initialised
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 9b57f014d79d..19a0ea08e098 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -286,7 +286,6 @@ DEFINE_EVENT(writeback_class, name, \
TP_PROTO(struct bdi_writeback *wb), \
TP_ARGS(wb))
-DEFINE_WRITEBACK_EVENT(writeback_nowork);
DEFINE_WRITEBACK_EVENT(writeback_wake_background);
TRACE_EVENT(writeback_bdi_register,
--
cgit v1.2.3-70-g09d2
From 8264c3214f28b52b399d9e03bfa7feec275a0d71 Mon Sep 17 00:00:00 2001
From: Rakesh Pandit <rakesh@tuxera.com>
Date: Mon, 9 Oct 2017 13:34:41 +0300
Subject: writeback: merge try_to_writeback_inodes_sb_nr() into caller
Since commit 925a6efb8ff0c ("Btrfs: stop using
try_to_writeback_inodes_sb_nr to flush delalloc") this function hasn't
been used outside so stop exporting it.
In addition we merge it into try_to_writeback_inodes_sb() which is the
only caller. Also change return type of try_to_writeback_inodes_sb to
void as the only user ext4 doesn't care.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/fs-writeback.c | 30 ++++++------------------------
include/linux/writeback.h | 4 +---
2 files changed, 7 insertions(+), 27 deletions(-)
(limited to 'include/linux/writeback.h')
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 9e24d604c59c..08f5debd07d1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -2376,37 +2376,19 @@ void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
EXPORT_SYMBOL(writeback_inodes_sb);
/**
- * try_to_writeback_inodes_sb_nr - try to start writeback if none underway
+ * try_to_writeback_inodes_sb - try to start writeback if none underway
* @sb: the superblock
- * @nr: the number of pages to write
- * @reason: the reason of writeback
+ * @reason: reason why some writeback work was initiated
*
- * Invoke writeback_inodes_sb_nr if no writeback is currently underway.
- * Returns 1 if writeback was started, 0 if not.
+ * Invoke __writeback_inodes_sb_nr if no writeback is currently underway.
*/
-bool try_to_writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr,
- enum wb_reason reason)
+void try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
if (!down_read_trylock(&sb->s_umount))
- return false;
+ return;
- __writeback_inodes_sb_nr(sb, nr, reason, true);
+ __writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason, true);
up_read(&sb->s_umount);
- return true;
-}
-EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr);
-
-/**
- * try_to_writeback_inodes_sb - try to start writeback if none underway
- * @sb: the superblock
- * @reason: reason why some writeback work was initiated
- *
- * Implement by try_to_writeback_inodes_sb_nr()
- * Returns 1 if writeback was started, 0 if not.
- */
-bool try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
-{
- return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
}
EXPORT_SYMBOL(try_to_writeback_inodes_sb);
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index dd1d2c23f743..e15ec14085ad 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -163,9 +163,7 @@ struct bdi_writeback;
void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
enum wb_reason reason);
-bool try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
-bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
- enum wb_reason reason);
+void try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason);
void sync_inodes_sb(struct super_block *);
void wakeup_flusher_threads(enum wb_reason reason);
void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi,
--
cgit v1.2.3-70-g09d2