From: Tejun Heo <tj@kernel.org>
To: axboe@kernel.dk
Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org,
hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org,
vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org,
linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com,
fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com,
khlebnikov@yandex-team.ru, Tejun Heo <tj@kernel.org>
Subject: [PATCH 44/51] writeback: implement bdi_wait_for_completion()
Date: Fri, 22 May 2015 17:13:58 -0400 [thread overview]
Message-ID: <1432329245-5844-45-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1432329245-5844-1-git-send-email-tj@kernel.org>
If the completion of a wb_writeback_work can be waited upon by setting
its ->done to a struct completion and waiting on it; however, for
cgroup writeback support, it's necessary to issue multiple work items
to multiple bdi_writebacks and wait for the completion of all.
This patch implements wb_completion which can wait for multiple work
items and replaces the struct completion with it. It can be defined
using DEFINE_WB_COMPLETION_ONSTACK(), used for multiple work items and
waited for by wb_wait_for_completion().
Nobody currently issues multiple work items and this patch doesn't
introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
---
fs/fs-writeback.c | 58 +++++++++++++++++++++++++++++++---------
include/linux/backing-dev-defs.h | 2 ++
mm/backing-dev.c | 1 +
3 files changed, 49 insertions(+), 12 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 22f1def..d7d4a1b 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -34,6 +34,10 @@
*/
#define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10))
+struct wb_completion {
+ atomic_t cnt;
+};
+
/*
* Passed into wb_writeback(), essentially a subset of writeback_control
*/
@@ -51,10 +55,23 @@ struct wb_writeback_work {
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
- struct completion *done; /* set if the caller waits */
+ struct wb_completion *done; /* set if the caller waits */
};
/*
+ * If one wants to wait for one or more wb_writeback_works, each work's
+ * ->done should be set to a wb_completion defined using the following
+ * macro. Once all work items are issued with wb_queue_work(), the caller
+ * can wait for the completion of all using wb_wait_for_completion(). Work
+ * items which are waited upon aren't freed automatically on completion.
+ */
+#define DEFINE_WB_COMPLETION_ONSTACK(cmpl) \
+ struct wb_completion cmpl = { \
+ .cnt = ATOMIC_INIT(1), \
+ }
+
+
+/*
* If an inode is constantly having its pages dirtied, but then the
* updates stop dirtytime_expire_interval seconds in the past, it's
* possible for the worst case time between when an inode has its
@@ -161,17 +178,34 @@ static void wb_queue_work(struct bdi_writeback *wb,
trace_writeback_queue(wb->bdi, work);
spin_lock_bh(&wb->work_lock);
- if (!test_bit(WB_registered, &wb->state)) {
- if (work->done)
- complete(work->done);
+ 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);
mod_delayed_work(bdi_wq, &wb->dwork, 0);
out_unlock:
spin_unlock_bh(&wb->work_lock);
}
+/**
+ * wb_wait_for_completion - wait for completion of bdi_writeback_works
+ * @bdi: bdi work items were issued to
+ * @done: target wb_completion
+ *
+ * Wait for one or more work items issued to @bdi with their ->done field
+ * set to @done, which should have been defined with
+ * DEFINE_WB_COMPLETION_ONSTACK(). This function returns after all such
+ * work items are completed. Work items which are waited upon aren't freed
+ * automatically on completion.
+ */
+static void wb_wait_for_completion(struct backing_dev_info *bdi,
+ struct wb_completion *done)
+{
+ atomic_dec(&done->cnt); /* put down the initial count */
+ wait_event(bdi->wb_waitq, !atomic_read(&done->cnt));
+}
+
#ifdef CONFIG_CGROUP_WRITEBACK
/**
@@ -1143,7 +1177,7 @@ static long wb_do_writeback(struct bdi_writeback *wb)
set_bit(WB_writeback_running, &wb->state);
while ((work = get_next_work_item(wb)) != NULL) {
- struct completion *done = work->done;
+ struct wb_completion *done = work->done;
trace_writeback_exec(wb->bdi, work);
@@ -1151,8 +1185,8 @@ static long wb_do_writeback(struct bdi_writeback *wb)
if (work->auto_free)
kfree(work);
- if (done)
- complete(done);
+ if (done && atomic_dec_and_test(&done->cnt))
+ wake_up_all(&wb->bdi->wb_waitq);
}
/*
@@ -1518,7 +1552,7 @@ void writeback_inodes_sb_nr(struct super_block *sb,
unsigned long nr,
enum wb_reason reason)
{
- DECLARE_COMPLETION_ONSTACK(done);
+ DEFINE_WB_COMPLETION_ONSTACK(done);
struct wb_writeback_work work = {
.sb = sb,
.sync_mode = WB_SYNC_NONE,
@@ -1533,7 +1567,7 @@ void writeback_inodes_sb_nr(struct super_block *sb,
return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
wb_queue_work(&bdi->wb, &work);
- wait_for_completion(&done);
+ wb_wait_for_completion(bdi, &done);
}
EXPORT_SYMBOL(writeback_inodes_sb_nr);
@@ -1600,7 +1634,7 @@ EXPORT_SYMBOL(try_to_writeback_inodes_sb);
*/
void sync_inodes_sb(struct super_block *sb)
{
- DECLARE_COMPLETION_ONSTACK(done);
+ DEFINE_WB_COMPLETION_ONSTACK(done);
struct wb_writeback_work work = {
.sb = sb,
.sync_mode = WB_SYNC_ALL,
@@ -1618,7 +1652,7 @@ void sync_inodes_sb(struct super_block *sb)
WARN_ON(!rwsem_is_locked(&sb->s_umount));
wb_queue_work(&bdi->wb, &work);
- wait_for_completion(&done);
+ wb_wait_for_completion(bdi, &done);
wait_sb_inodes(sb);
}
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index 8c857d7..97a92fa 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -155,6 +155,8 @@ struct backing_dev_info {
struct rb_root cgwb_congested_tree; /* their congested states */
atomic_t usage_cnt; /* counts both cgwbs and cgwb_contested's */
#endif
+ wait_queue_head_t wb_waitq;
+
struct device *dev;
struct timer_list laptop_mode_wb_timer;
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index d2f16fc9..ad5608d 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -768,6 +768,7 @@ int bdi_init(struct backing_dev_info *bdi)
bdi->max_ratio = 100;
bdi->max_prop_frac = FPROP_FRAC_BASE;
INIT_LIST_HEAD(&bdi->bdi_list);
+ init_waitqueue_head(&bdi->wb_waitq);
err = wb_init(&bdi->wb, bdi, GFP_KERNEL);
if (err)
--
2.4.0
next prev parent reply other threads:[~2015-05-22 21:19 UTC|newest]
Thread overview: 131+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-22 21:13 [PATCHSET 1/3 v4 block/for-4.2/core] writeback: cgroup writeback support Tejun Heo
2015-05-22 21:13 ` [PATCH 01/51] page_writeback: revive cancel_dirty_page() in a restricted form Tejun Heo
2015-05-22 21:13 ` [PATCH 02/51] memcg: add per cgroup dirty page accounting Tejun Heo
2015-05-22 21:13 ` [PATCH 03/51] blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.h Tejun Heo
2015-05-22 21:13 ` [PATCH 04/51] update !CONFIG_BLK_CGROUP dummies in include/linux/blk-cgroup.h Tejun Heo
2015-05-22 21:13 ` [PATCH 05/51] blkcg: always create the blkcg_gq for the root blkcg Tejun Heo
2015-05-22 21:13 ` [PATCH 06/51] memcg: add mem_cgroup_root_css Tejun Heo
2015-06-17 14:56 ` Michal Hocko
2015-06-17 18:25 ` Tejun Heo
2015-06-18 11:12 ` Michal Hocko
2015-06-18 17:49 ` Tejun Heo
2015-06-19 9:18 ` Michal Hocko
2015-06-19 15:17 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 07/51] blkcg: add blkcg_root_css Tejun Heo
2015-05-22 21:13 ` [PATCH 08/51] cgroup, block: implement task_get_css() and use it in bio_associate_current() Tejun Heo
2015-05-22 21:13 ` [PATCH 09/51] blkcg: implement task_get_blkcg_css() Tejun Heo
2015-05-22 21:13 ` [PATCH 10/51] blkcg: implement bio_associate_blkcg() Tejun Heo
2015-05-22 21:13 ` [PATCH 11/51] memcg: implement mem_cgroup_css_from_page() Tejun Heo
2015-05-22 23:28 ` Johannes Weiner
2015-05-24 21:24 ` Tejun Heo
2015-05-27 12:58 ` Johannes Weiner
2015-05-27 16:13 ` [PATCH v2 " Tejun Heo
2015-05-27 17:09 ` Johannes Weiner
2015-05-27 17:48 ` Tejun Heo
2015-05-27 17:57 ` [PATCH v3 " Tejun Heo
2015-05-28 0:00 ` [PATCH v4 " Tejun Heo
2015-05-22 21:13 ` [PATCH 12/51] writeback: move backing_dev_info->state into bdi_writeback Tejun Heo
2015-05-22 21:13 ` [PATCH 13/51] writeback: move backing_dev_info->bdi_stat[] " Tejun Heo
2015-05-22 21:13 ` [PATCH 14/51] writeback: move bandwidth related fields from backing_dev_info " Tejun Heo
2015-05-22 21:13 ` [PATCH 15/51] writeback: s/bdi/wb/ in mm/page-writeback.c Tejun Heo
2015-05-22 21:13 ` [PATCH 16/51] writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback Tejun Heo
2015-06-07 0:49 ` Sasha Levin
2015-06-08 5:57 ` [PATCH block/for-4.2-writeback] v9fs: fix error handling in v9fs_session_init() Tejun Heo
2015-06-08 15:10 ` Jens Axboe
2015-05-22 21:13 ` [PATCH 17/51] writeback: reorganize mm/backing-dev.c Tejun Heo
2015-05-22 21:13 ` [PATCH 18/51] writeback: separate out include/linux/backing-dev-defs.h Tejun Heo
2015-05-22 21:13 ` [PATCH 19/51] bdi: make inode_to_bdi() inline Tejun Heo
2015-06-30 6:47 ` Jan Kara
2015-05-22 21:13 ` [PATCH 20/51] writeback: add @gfp to wb_init() Tejun Heo
2015-05-22 21:13 ` [PATCH 21/51] bdi: separate out congested state into a separate struct Tejun Heo
2015-06-30 9:21 ` Jan Kara
2015-05-22 21:13 ` [PATCH 22/51] writeback: add {CONFIG|BDI_CAP|FS}_CGROUP_WRITEBACK Tejun Heo
2015-06-30 9:37 ` Jan Kara
2015-07-02 1:10 ` Tejun Heo
2015-07-03 10:49 ` Jan Kara
2015-07-03 17:14 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 23/51] writeback: make backing_dev_info host cgroup-specific bdi_writebacks Tejun Heo
2015-06-30 10:14 ` Jan Kara
2015-05-22 21:13 ` [PATCH 24/51] writeback, blkcg: associate each blkcg_gq with the corresponding bdi_writeback_congested Tejun Heo
2015-06-30 9:08 ` Jan Kara
2015-05-22 21:13 ` [PATCH 25/51] writeback: attribute stats to the matching per-cgroup bdi_writeback Tejun Heo
2015-06-30 14:17 ` Jan Kara
2015-05-22 21:13 ` [PATCH 26/51] writeback: let balance_dirty_pages() work on the matching cgroup bdi_writeback Tejun Heo
2015-06-30 14:31 ` Jan Kara
2015-07-02 1:26 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 27/51] writeback: make congestion functions per bdi_writeback Tejun Heo
2015-06-30 14:50 ` Jan Kara
2015-05-22 21:13 ` [PATCH 28/51] writeback, blkcg: restructure blk_{set|clear}_queue_congested() Tejun Heo
2015-06-30 15:02 ` Jan Kara
2015-07-02 1:38 ` Tejun Heo
2015-07-03 12:16 ` Jan Kara
2015-05-22 21:13 ` [PATCH 29/51] writeback, blkcg: propagate non-root blkcg congestion state Tejun Heo
2015-06-30 15:03 ` Jan Kara
2015-05-22 21:13 ` [PATCH 30/51] writeback: implement and use inode_congested() Tejun Heo
2015-06-30 15:21 ` Jan Kara
2015-07-02 1:46 ` Tejun Heo
2015-07-03 12:17 ` Jan Kara
2015-07-03 17:07 ` Tejun Heo
2015-07-04 15:12 ` [PATCH block/for-4.3] writeback: explain why @inode is allowed to be NULL for inode_congested() Tejun Heo
2015-07-08 8:12 ` Jan Kara
2015-05-22 21:13 ` [PATCH 31/51] writeback: implement WB_has_dirty_io wb_state flag Tejun Heo
2015-06-30 15:42 ` Jan Kara
2015-05-22 21:13 ` [PATCH 32/51] writeback: implement backing_dev_info->tot_write_bandwidth Tejun Heo
2015-06-30 16:14 ` Jan Kara
2015-06-30 16:42 ` Jan Kara
2015-05-22 21:13 ` [PATCH 33/51] writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account Tejun Heo
2015-06-30 16:48 ` Jan Kara
2015-07-02 2:01 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 34/51] writeback: don't issue wb_writeback_work if clean Tejun Heo
2015-06-30 16:18 ` Jan Kara
2015-05-22 21:13 ` [PATCH 35/51] writeback: make bdi->min/max_ratio handling cgroup writeback aware Tejun Heo
2015-07-01 7:00 ` Jan Kara
2015-05-22 21:13 ` [PATCH 36/51] writeback: implement bdi_for_each_wb() Tejun Heo
2015-07-01 7:27 ` Jan Kara
2015-07-02 2:22 ` Tejun Heo
2015-07-03 12:26 ` Jan Kara
2015-07-03 17:06 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 37/51] writeback: remove bdi_start_writeback() Tejun Heo
2015-07-01 7:30 ` Jan Kara
2015-05-22 21:13 ` [PATCH 38/51] writeback: make laptop_mode_timer_fn() handle multiple bdi_writeback's Tejun Heo
2015-07-01 7:32 ` Jan Kara
2015-05-22 21:13 ` [PATCH 39/51] writeback: make writeback_in_progress() take bdi_writeback instead of backing_dev_info Tejun Heo
2015-07-01 7:47 ` Jan Kara
2015-07-02 2:28 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 40/51] writeback: make bdi_start_background_writeback() " Tejun Heo
2015-07-01 7:50 ` Jan Kara
2015-07-02 2:29 ` Tejun Heo
2015-07-06 19:36 ` [PATCH block/for-4.3] writeback: update writeback tracepoints to report cgroup Tejun Heo
2015-07-08 8:17 ` Jan Kara
2015-05-22 21:13 ` [PATCH 41/51] writeback: make wakeup_flusher_threads() handle multiple bdi_writeback's Tejun Heo
2015-07-01 8:15 ` Jan Kara
2015-07-02 2:37 ` Tejun Heo
2015-07-03 13:02 ` Jan Kara
2015-07-03 16:33 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 42/51] writeback: make wakeup_dirtytime_writeback() " Tejun Heo
2015-07-01 8:20 ` Jan Kara
2015-05-22 21:13 ` [PATCH 43/51] writeback: add wb_writeback_work->auto_free Tejun Heo
2015-05-22 21:13 ` Tejun Heo [this message]
2015-07-01 16:04 ` [PATCH 44/51] writeback: implement bdi_wait_for_completion() Jan Kara
2015-07-02 3:06 ` Tejun Heo
2015-07-03 12:36 ` Jan Kara
2015-07-03 17:02 ` Tejun Heo
2015-07-01 16:09 ` Jan Kara
2015-07-02 3:01 ` Tejun Heo
2015-05-22 21:13 ` [PATCH 45/51] writeback: implement wb_wait_for_single_work() Tejun Heo
2015-07-01 19:07 ` Jan Kara
2015-07-02 3:07 ` Tejun Heo
2015-07-03 22:12 ` [PATCH block/for-4.3] writeback: remove wb_writeback_work->single_wait/done Tejun Heo
2015-07-08 8:24 ` Jan Kara
2015-05-22 21:14 ` [PATCH 46/51] writeback: restructure try_writeback_inodes_sb[_nr]() Tejun Heo
2015-05-22 21:14 ` [PATCH 47/51] writeback: make writeback initiation functions handle multiple bdi_writeback's Tejun Heo
2015-05-22 21:14 ` [PATCH 48/51] writeback: dirty inodes against their matching cgroup bdi_writeback's Tejun Heo
2015-07-01 19:16 ` Jan Kara
2015-05-22 21:14 ` [PATCH 49/51] buffer, writeback: make __block_write_full_page() honor cgroup writeback Tejun Heo
2015-07-01 19:21 ` Jan Kara
2015-07-01 19:28 ` Jan Kara
2015-05-22 21:14 ` [PATCH 50/51] mpage: make __mpage_writepage() " Tejun Heo
2015-07-01 19:26 ` Jan Kara
2015-05-22 21:14 ` [PATCH 51/51] ext2: enable cgroup writeback support Tejun Heo
2015-07-01 19:29 ` Jan Kara
2015-07-02 3:08 ` Tejun Heo
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