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| author | Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> | 2019-02-10 23:53:21 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-02-10 23:53:21 -0500 |
| commit | a297b2fcee461e40df763e179cbbfba5a9e572d2 (patch) | |
| tree | b15dfad165f70a7b360b2d94676e2842f9d9cf0b /fs | |
| parent | 16e08b14a4550bb167c48e918b26ef0d4980e9d1 (diff) | |
| download | linux-a297b2fcee461e40df763e179cbbfba5a9e572d2.tar.bz2 | |
ext4: unlock unused_pages timely when doing writeback
In mpage_add_bh_to_extent(), when accumulated extents length is greater
than MAX_WRITEPAGES_EXTENT_LEN or buffer head's b_stat is not equal, we
will not continue to search unmapped area for this page, but note this
page is locked, and will only be unlocked in mpage_release_unused_pages()
after ext4_io_submit, if io also is throttled by blk-throttle or similar
io qos, we will hold this page locked for a while, it's unnecessary.
I think the best fix is to refactor mpage_add_bh_to_extent() to let it
return some hints whether to unlock this page, but given that we will
improve dioread_nolock later, we can let it done later, so currently
the simple fix would just call mpage_release_unused_pages() before
ext4_io_submit().
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/inode.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index dd4641f3cdb9..9c3402ec85bc 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2829,12 +2829,12 @@ retry: goto unplug; } ret = mpage_prepare_extent_to_map(&mpd); + /* Unlock pages we didn't use */ + mpage_release_unused_pages(&mpd, false); /* Submit prepared bio */ ext4_io_submit(&mpd.io_submit); ext4_put_io_end_defer(mpd.io_submit.io_end); mpd.io_submit.io_end = NULL; - /* Unlock pages we didn't use */ - mpage_release_unused_pages(&mpd, false); if (ret < 0) goto unplug; @@ -2902,10 +2902,11 @@ retry: handle = NULL; mpd.do_map = 0; } - /* Submit prepared bio */ - ext4_io_submit(&mpd.io_submit); /* Unlock pages we didn't use */ mpage_release_unused_pages(&mpd, give_up_on_write); + /* Submit prepared bio */ + ext4_io_submit(&mpd.io_submit); + /* * Drop our io_end reference we got from init. We have * to be careful and use deferred io_end finishing if |