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 33/51] writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account
Date: Fri, 22 May 2015 17:13:47 -0400 [thread overview]
Message-ID: <1432329245-5844-34-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1432329245-5844-1-git-send-email-tj@kernel.org>
bdi_has_dirty_io() used to only reflect whether the root wb
(bdi_writeback) has dirty inodes. For cgroup writeback support, it
needs to take all active wb's into account. If any wb on the bdi has
dirty inodes, bdi_has_dirty_io() should return true.
To achieve that, as inode_wb_list_{move|del}_locked() now keep track
of the dirty state transition of each wb, the number of dirty wbs can
be counted in the bdi; however, bdi is already aggregating
wb->avg_write_bandwidth which can easily be guaranteed to be > 0 when
there are any dirty inodes by ensuring wb->avg_write_bandwidth can't
dip below 1. bdi_has_dirty_io() can simply test whether
bdi->tot_write_bandwidth is zero or not.
While this bumps the value of wb->avg_write_bandwidth to one when it
used to be zero, this shouldn't cause any meaningful behavior
difference.
bdi_has_dirty_io() is made an inline function which tests whether
->tot_write_bandwidth is non-zero. Also, WARN_ON_ONCE()'s on its
value are added to inode_wb_list_{move|del}_locked().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
---
fs/fs-writeback.c | 5 +++--
include/linux/backing-dev-defs.h | 8 ++++++--
include/linux/backing-dev.h | 10 +++++++++-
mm/backing-dev.c | 5 -----
mm/page-writeback.c | 10 +++++++---
5 files changed, 25 insertions(+), 13 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index bbccf68..c98d392 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -99,6 +99,7 @@ static bool wb_io_lists_populated(struct bdi_writeback *wb)
return false;
} else {
set_bit(WB_has_dirty_io, &wb->state);
+ WARN_ON_ONCE(!wb->avg_write_bandwidth);
atomic_long_add(wb->avg_write_bandwidth,
&wb->bdi->tot_write_bandwidth);
return true;
@@ -110,8 +111,8 @@ static void wb_io_lists_depopulated(struct bdi_writeback *wb)
if (wb_has_dirty_io(wb) && list_empty(&wb->b_dirty) &&
list_empty(&wb->b_io) && list_empty(&wb->b_more_io)) {
clear_bit(WB_has_dirty_io, &wb->state);
- atomic_long_sub(wb->avg_write_bandwidth,
- &wb->bdi->tot_write_bandwidth);
+ WARN_ON_ONCE(atomic_long_sub_return(wb->avg_write_bandwidth,
+ &wb->bdi->tot_write_bandwidth) < 0);
}
}
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index d631a61..8c857d7 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -98,7 +98,7 @@ struct bdi_writeback {
unsigned long dirtied_stamp;
unsigned long written_stamp; /* pages written at bw_time_stamp */
unsigned long write_bandwidth; /* the estimated write bandwidth */
- unsigned long avg_write_bandwidth; /* further smoothed write bw */
+ unsigned long avg_write_bandwidth; /* further smoothed write bw, > 0 */
/*
* The base dirty throttle rate, re-calculated on every 200ms.
@@ -142,7 +142,11 @@ struct backing_dev_info {
unsigned int min_ratio;
unsigned int max_ratio, max_prop_frac;
- atomic_long_t tot_write_bandwidth; /* sum of active avg_write_bw */
+ /*
+ * Sum of avg_write_bw of wbs with dirty inodes. > 0 if there are
+ * any dirty wbs, which is depended upon by bdi_has_dirty().
+ */
+ atomic_long_t tot_write_bandwidth;
struct bdi_writeback wb; /* the root writeback info for this bdi */
struct bdi_writeback_congested wb_congested; /* its congested state */
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 3c8403c..0839e44 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -29,7 +29,6 @@ void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
enum wb_reason reason);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
void wb_workfn(struct work_struct *work);
-bool bdi_has_dirty_io(struct backing_dev_info *bdi);
void wb_wakeup_delayed(struct bdi_writeback *wb);
extern spinlock_t bdi_lock;
@@ -42,6 +41,15 @@ static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
return test_bit(WB_has_dirty_io, &wb->state);
}
+static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi)
+{
+ /*
+ * @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are
+ * any dirty wbs. See wb_update_write_bandwidth().
+ */
+ return atomic_long_read(&bdi->tot_write_bandwidth);
+}
+
static inline void __add_wb_stat(struct bdi_writeback *wb,
enum wb_stat_item item, s64 amount)
{
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 161ddf1..d2f16fc9 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -256,11 +256,6 @@ static int __init default_bdi_init(void)
}
subsys_initcall(default_bdi_init);
-bool bdi_has_dirty_io(struct backing_dev_info *bdi)
-{
- return wb_has_dirty_io(&bdi->wb);
-}
-
/*
* This function is used when the first inode for this wb is marked dirty. It
* wakes-up the corresponding bdi thread which should then take care of the
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index c95eb24..99b8846 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -881,9 +881,13 @@ static void wb_update_write_bandwidth(struct bdi_writeback *wb,
avg += (old - avg) >> 3;
out:
- if (wb_has_dirty_io(wb))
- atomic_long_add(avg - wb->avg_write_bandwidth,
- &wb->bdi->tot_write_bandwidth);
+ /* keep avg > 0 to guarantee that tot > 0 if there are dirty wbs */
+ avg = max(avg, 1LU);
+ if (wb_has_dirty_io(wb)) {
+ long delta = avg - wb->avg_write_bandwidth;
+ WARN_ON_ONCE(atomic_long_add_return(delta,
+ &wb->bdi->tot_write_bandwidth) <= 0);
+ }
wb->write_bandwidth = bw;
wb->avg_write_bandwidth = avg;
}
--
2.4.0
--
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next prev parent reply other threads:[~2015-05-22 21:13 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
[not found] ` <20150617145642.GI25056-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2015-06-17 18:25 ` Tejun Heo
[not found] ` <20150617182500.GI22637-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-06-18 11:12 ` Michal Hocko
2015-06-18 17:49 ` Tejun Heo
[not found] ` <20150618174930.GA12934-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2015-06-19 9:18 ` Michal Hocko
[not found] ` <20150619091848.GE4913-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
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
[not found] ` <1432329245-5844-12-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-05-22 23:28 ` Johannes Weiner
2015-05-24 21:24 ` Tejun Heo
[not found] ` <20150524212440.GD7099-piEFEHQLUPpN0TnZuCh8vA@public.gmane.org>
2015-05-27 12:58 ` Johannes Weiner
2015-05-27 16:13 ` [PATCH v2 " Tejun Heo
2015-05-27 17:09 ` Johannes Weiner
[not found] ` <20150527170955.GA25324-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
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
[not found] ` <1432329245-5844-25-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <1432329245-5844-26-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <1432329245-5844-29-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-06-30 15:02 ` Jan Kara
2015-07-02 1:38 ` Tejun Heo
[not found] ` <20150702013815.GE26440-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
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
[not found] ` <20150703121721.GJ23329-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
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
[not found] ` <1432329245-5844-33-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-06-30 16:14 ` Jan Kara
2015-06-30 16:42 ` Jan Kara
2015-05-22 21:13 ` Tejun Heo [this message]
2015-06-30 16:48 ` [PATCH 33/51] writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account Jan Kara
[not found] ` <20150630164824.GU7252-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
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
[not found] ` <1432329245-5844-35-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <1432329245-5844-36-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-07-01 7:00 ` Jan Kara
2015-05-22 21:13 ` [PATCH 36/51] writeback: implement bdi_for_each_wb() Tejun Heo
[not found] ` <1432329245-5844-37-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-07-01 7:27 ` Jan Kara
2015-07-02 2:22 ` Tejun Heo
[not found] ` <20150702022226.GH26440-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
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
[not found] ` <1432329245-5844-38-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <1432329245-5844-39-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <1432329245-5844-40-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <20150701075009.GA7252-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
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
[not found] ` <20150703130213.GM23329-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
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 ` [PATCH 44/51] writeback: implement bdi_wait_for_completion() Tejun Heo
[not found] ` <1432329245-5844-45-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-07-01 16:04 ` 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
[not found] ` <20150701160918.GH7252-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
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
[not found] ` <1432329245-5844-49-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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
[not found] ` <20150701192102.GK7252-+0h/O2h83AeN3ZZ/Hiejyg@public.gmane.org>
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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