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author | Tejun Heo <tj@kernel.org> | 2015-05-22 17:13:47 -0400 |
---|---|---|
committer | Jens Axboe <axboe@fb.com> | 2015-06-02 08:33:36 -0600 |
commit | 95a46c65e3c09edb9f17dabf2dc16670cd328739 (patch) | |
tree | 2ff8187223f5f5671394dd9ee84719f3ff934a14 /fs | |
parent | 766a9d6e60578f1ef6de71f89f022084f8bffc82 (diff) | |
download | linux-stable-95a46c65e3c09edb9f17dabf2dc16670cd328739.tar.gz linux-stable-95a46c65e3c09edb9f17dabf2dc16670cd328739.tar.bz2 linux-stable-95a46c65e3c09edb9f17dabf2dc16670cd328739.zip |
writeback: make bdi_has_dirty_io() take multiple bdi_writeback's into account
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>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/fs-writeback.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index bbccf68b38db..c98d3923d9a9 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); } } |