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,
Tejun Heo <tj@kernel.org>
Subject: [PATCH 44/48] writeback: make writeback initiation functions handle multiple bdi_writeback's
Date: Mon, 23 Mar 2015 00:54:55 -0400 [thread overview]
Message-ID: <1427086499-15657-45-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1427086499-15657-1-git-send-email-tj@kernel.org>
[try_]writeback_inodes_sb[_nr]() and sync_inodes_sb() currently only
handle dirty inodes on the root wb (bdi_writeback) of the target bdi.
This patch implements bdi_split_work_to_wbs() and use it to make these
functions handle multiple wb's.
bdi_split_work_to_wbs() takes a base wb_writeback_work and create
clones of it and issue them to the wb's of the target bdi. The base
work's nr_pages is distributed using wb_split_bdi_pages() -
ie. according to each wb's write bandwidth's proportion in the bdi.
Cloning a bdi involves memory allocation which may fail. In such
cases, bdi_split_work_to_wbs() issues the base work directly and waits
for its completion before proceeding to the next wb to guarantee
forward progress and correctness under memory pressure.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
---
fs/fs-writeback.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 91 insertions(+), 5 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index be374ae..57b2282 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -289,6 +289,80 @@ static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages)
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
+ * @base_work: wb_writeback_work to issue
+ * @skip_if_busy: skip wb's which already have writeback in progress
+ *
+ * Split and issue @base_work to all wb's (bdi_writeback's) of @bdi which
+ * have dirty inodes. If @base_work->nr_page isn't %LONG_MAX, it's
+ * distributed to the busy wbs according to each wb's proportion in the
+ * total active write bandwidth of @bdi.
+ */
+static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
+ struct wb_writeback_work *base_work,
+ bool skip_if_busy)
+{
+ long nr_pages = base_work->nr_pages;
+ int next_blkcg_id = 0;
+ struct bdi_writeback *wb;
+ struct wb_iter iter;
+
+ might_sleep();
+
+ if (!bdi_has_dirty_io(bdi))
+ return;
+restart:
+ rcu_read_lock();
+ bdi_for_each_wb(wb, bdi, &iter, next_blkcg_id) {
+ if (!wb_has_dirty_io(wb) ||
+ (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;
+ }
+ }
+ rcu_read_unlock();
+}
+
#else /* CONFIG_CGROUP_WRITEBACK */
static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages)
@@ -296,6 +370,21 @@ static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages)
return nr_pages;
}
+static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
+ struct wb_writeback_work *base_work,
+ bool skip_if_busy)
+{
+ might_sleep();
+
+ if (bdi_has_dirty_io(bdi) &&
+ (!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);
+ }
+}
+
#endif /* CONFIG_CGROUP_WRITEBACK */
void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
@@ -1528,10 +1617,7 @@ static void __writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr,
return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- if (skip_if_busy && writeback_in_progress(&bdi->wb))
- return;
-
- wb_queue_work(&bdi->wb, &work);
+ bdi_split_work_to_wbs(sb->s_bdi, &work, skip_if_busy);
wb_wait_for_completion(bdi, &done);
}
@@ -1629,7 +1715,7 @@ void sync_inodes_sb(struct super_block *sb)
return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- wb_queue_work(&bdi->wb, &work);
+ bdi_split_work_to_wbs(bdi, &work, false);
wb_wait_for_completion(bdi, &done);
wait_sb_inodes(sb);
--
2.1.0
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next prev parent reply other threads:[~2015-03-23 4:54 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 4:54 [PATCHSET 1/3 v2 block/for-4.1/core] writeback: cgroup writeback support Tejun Heo
2015-03-23 4:54 ` [PATCH 01/48] memcg: add per cgroup dirty page accounting Tejun Heo
2015-03-23 4:54 ` [PATCH 02/48] blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.h Tejun Heo
2015-03-23 4:54 ` [PATCH 04/48] memcg: add mem_cgroup_root_css Tejun Heo
2015-03-23 4:54 ` [PATCH 05/48] blkcg: add blkcg_root_css Tejun Heo
2015-03-23 4:54 ` [PATCH 06/48] cgroup, block: implement task_get_css() and use it in bio_associate_current() Tejun Heo
2015-03-23 4:54 ` [PATCH 07/48] blkcg: implement task_get_blkcg_css() Tejun Heo
2015-03-23 4:54 ` [PATCH 08/48] blkcg: implement bio_associate_blkcg() Tejun Heo
2015-03-23 4:54 ` [PATCH 09/48] memcg: implement mem_cgroup_css_from_page() Tejun Heo
2015-03-23 4:54 ` [PATCH 10/48] writeback: move backing_dev_info->state into bdi_writeback Tejun Heo
2015-03-23 4:54 ` [PATCH 11/48] writeback: move backing_dev_info->bdi_stat[] " Tejun Heo
2015-03-23 4:54 ` [PATCH 12/48] writeback: move bandwidth related fields from backing_dev_info " Tejun Heo
2015-03-23 4:54 ` [PATCH 13/48] writeback: s/bdi/wb/ in mm/page-writeback.c Tejun Heo
2015-03-23 4:54 ` [PATCH 14/48] writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback Tejun Heo
2015-03-23 4:54 ` [PATCH 15/48] writeback: reorganize mm/backing-dev.c Tejun Heo
2015-03-23 4:54 ` [PATCH 16/48] writeback: separate out include/linux/backing-dev-defs.h Tejun Heo
2015-03-23 4:54 ` [PATCH 17/48] bdi: make inode_to_bdi() inline Tejun Heo
2015-03-23 4:54 ` [PATCH 18/48] writeback: add @gfp to wb_init() Tejun Heo
2015-03-23 4:54 ` [PATCH 19/48] bdi: separate out congested state into a separate struct Tejun Heo
2015-03-23 4:54 ` [PATCH 20/48] writeback: add {CONFIG|BDI_CAP|FS}_CGROUP_WRITEBACK Tejun Heo
2015-03-23 4:54 ` [PATCH 21/48] writeback: make backing_dev_info host cgroup-specific bdi_writebacks Tejun Heo
2015-03-27 21:06 ` Vivek Goyal
2015-03-27 21:41 ` Tejun Heo
2015-03-23 4:54 ` [PATCH 22/48] writeback, blkcg: associate each blkcg_gq with the corresponding bdi_writeback_congested Tejun Heo
2015-03-23 4:54 ` [PATCH 24/48] writeback: let balance_dirty_pages() work on the matching cgroup bdi_writeback Tejun Heo
2015-03-23 4:54 ` [PATCH 25/48] writeback: make congestion functions per bdi_writeback Tejun Heo
2015-03-23 4:54 ` [PATCH 26/48] writeback, blkcg: restructure blk_{set|clear}_queue_congested() Tejun Heo
2015-03-23 4:54 ` [PATCH 28/48] writeback: implement and use mapping_congested() Tejun Heo
[not found] ` <1427086499-15657-29-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-03-27 18:06 ` Vivek Goyal
2015-03-27 21:46 ` Tejun Heo
2015-03-23 4:54 ` [PATCH 29/48] writeback: implement WB_has_dirty_io wb_state flag Tejun Heo
2015-03-23 4:54 ` [PATCH 30/48] writeback: implement backing_dev_info->tot_write_bandwidth Tejun Heo
2015-03-23 4:54 ` [PATCH 31/48] writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account Tejun Heo
2015-03-23 4:54 ` [PATCH 32/48] writeback: don't issue wb_writeback_work if clean Tejun Heo
2015-03-23 4:54 ` [PATCH 33/48] writeback: make bdi->min/max_ratio handling cgroup writeback aware Tejun Heo
2015-03-23 4:54 ` [PATCH 34/48] writeback: implement bdi_for_each_wb() Tejun Heo
2015-03-23 4:54 ` [PATCH 35/48] writeback: remove bdi_start_writeback() Tejun Heo
2015-03-23 4:54 ` [PATCH 36/48] writeback: make laptop_mode_timer_fn() handle multiple bdi_writeback's Tejun Heo
2015-03-23 4:54 ` [PATCH 37/48] writeback: make writeback_in_progress() take bdi_writeback instead of backing_dev_info Tejun Heo
2015-03-23 4:54 ` [PATCH 38/48] writeback: make bdi_start_background_writeback() " Tejun Heo
2015-03-23 4:54 ` [PATCH 39/48] writeback: make wakeup_flusher_threads() handle multiple bdi_writeback's Tejun Heo
2015-03-23 4:54 ` [PATCH 40/48] writeback: add wb_writeback_work->auto_free Tejun Heo
2015-03-23 4:54 ` [PATCH 41/48] writeback: implement bdi_wait_for_completion() Tejun Heo
2015-03-23 4:54 ` [PATCH 42/48] writeback: implement wb_wait_for_single_work() Tejun Heo
2015-03-23 4:54 ` Tejun Heo [this message]
2015-03-23 4:54 ` [PATCH 45/48] writeback: dirty inodes against their matching cgroup bdi_writeback's Tejun Heo
2015-03-23 4:54 ` [PATCH 46/48] buffer, writeback: make __block_write_full_page() honor cgroup writeback Tejun Heo
2015-03-23 4:54 ` [PATCH 47/48] mpage: make __mpage_writepage() " Tejun Heo
2015-03-23 4:54 ` [PATCH 48/48] ext2: enable cgroup writeback support Tejun Heo
[not found] ` <1427086499-15657-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-03-23 4:54 ` [PATCH 03/48] update !CONFIG_BLK_CGROUP dummies in include/linux/blk-cgroup.h Tejun Heo
2015-03-23 4:54 ` [PATCH 23/48] writeback: attribute stats to the matching per-cgroup bdi_writeback Tejun Heo
2015-03-23 4:54 ` [PATCH 27/48] writeback, blkcg: propagate non-root blkcg congestion state Tejun Heo
2015-03-23 4:54 ` [PATCH 43/48] writeback: restructure try_writeback_inodes_sb[_nr]() Tejun Heo
2015-03-25 15:40 ` [PATCHSET 1/3 v2 block/for-4.1/core] writeback: cgroup writeback support Vivek Goyal
[not found] ` <20150325154022.GC29728-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-03-25 16:01 ` Tejun Heo
2015-03-31 15:26 ` Tejun Heo
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