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| author | Dennis Zhou (Facebook) <dennisszhou@gmail.com> | 2018-09-11 14:41:32 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-09-21 20:29:11 -0600 |
| commit | bdc2491708c47601603918a9a20acddef6e1d814 (patch) | |
| tree | e10633b8836287b7c29c040665f6518db20f8d4a /Documentation/admin-guide | |
| parent | 74b7c02a9bc124ee3df0d77880ee26db0a325516 (diff) | |
| download | lwn-bdc2491708c47601603918a9a20acddef6e1d814.tar.gz lwn-bdc2491708c47601603918a9a20acddef6e1d814.zip | |
blkcg: associate writeback bios with a blkg
One of the goals of this series is to remove a separate reference to
the css of the bio. This can and should be accessed via bio_blkcg. In
this patch, the wbc_init_bio call is changed such that it must be called
after a queue has been associated with the bio.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 184193bcb262..caf36105a1c7 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1857,8 +1857,10 @@ following two functions. wbc_init_bio(@wbc, @bio) Should be called for each bio carrying writeback data and - associates the bio with the inode's owner cgroup. Can be - called anytime between bio allocation and submission. + associates the bio with the inode's owner cgroup and the + corresponding request queue. This must be called after + a queue (device) has been associated with the bio and + before submission. wbc_account_io(@wbc, @page, @bytes) Should be called for each data segment being written out. @@ -1877,7 +1879,7 @@ the configuration, the bio may be executed at a lower priority and if the writeback session is holding shared resources, e.g. a journal entry, may lead to priority inversion. There is no one easy solution for the problem. Filesystems can try to work around specific problem -cases by skipping wbc_init_bio() or using bio_associate_blkcg() +cases by skipping wbc_init_bio() or using bio_associate_create_blkg() directly. |