From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Tejun Heo <tj@kernel.org>
Cc: Dennis Zhou <dennis@kernel.org>, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
dm-devel@redhat.com, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org
Subject: [PATCH 04/14] block: merge __bio_associate_blkg into bio_associate_blkg_from_css
Date: Sat, 27 Jun 2020 09:31:49 +0200 [thread overview]
Message-ID: <20200627073159.2447325-5-hch@lst.de> (raw)
In-Reply-To: <20200627073159.2447325-1-hch@lst.de>
Merge __bio_associate_blkg into the only caller, which allows to slightly
reduce the RCU crticial section and better explain the code flow.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/bio.c | 45 +++++++++++++--------------------------------
1 file changed, 13 insertions(+), 32 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index e1d01acce8070c..bc8de2432e3645 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1628,52 +1628,33 @@ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
EXPORT_SYMBOL(bioset_init_from_src);
#ifdef CONFIG_BLK_CGROUP
-
-/**
- * __bio_associate_blkg - associate a bio with the a blkg
- * @bio: target bio
- * @blkg: the blkg to associate
- *
- * This tries to associate @bio with the specified @blkg. Association failure
- * is handled by walking up the blkg tree. Therefore, the blkg associated can
- * be anything between @blkg and the root_blkg. This situation only happens
- * when a cgroup is dying and then the remaining bios will spill to the closest
- * alive blkg.
- *
- * A reference will be taken on the @blkg and will be released when @bio is
- * freed.
- */
-static void __bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg)
-{
- if (bio->bi_blkg)
- blkg_put(bio->bi_blkg);
- bio->bi_blkg = blkg_tryget_closest(blkg);
-}
-
/**
* bio_associate_blkg_from_css - associate a bio with a specified css
* @bio: target bio
* @css: target css
*
* Associate @bio with the blkg found by combining the css's blkg and the
- * request_queue of the @bio. This falls back to the queue's root_blkg if
- * the association fails with the css.
+ * request_queue of the @bio. An association failure is handled by walking up
+ * the blkg tree. Therefore, the blkg associated can be anything between @blkg
+ * and q->root_blkg. This situation only happens when a cgroup is dying and
+ * then the remaining bios will spill to the closest alive blkg.
+ *
+ * A reference will be taken on the blkg and will be released when @bio is
+ * freed.
*/
void bio_associate_blkg_from_css(struct bio *bio,
struct cgroup_subsys_state *css)
{
struct request_queue *q = bio->bi_disk->queue;
- struct blkcg_gq *blkg;
+ struct blkcg_gq *blkg = q->root_blkg;
- rcu_read_lock();
+ if (bio->bi_blkg)
+ blkg_put(bio->bi_blkg);
- if (!css || !css->parent)
- blkg = q->root_blkg;
- else
+ rcu_read_lock();
+ if (css && css->parent)
blkg = blkg_lookup_create(css_to_blkcg(css), q);
-
- __bio_associate_blkg(bio, blkg);
-
+ bio->bi_blkg = blkg_tryget_closest(blkg);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
--
2.26.2
next prev parent reply other threads:[~2020-06-27 7:31 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-27 7:31 drive-by blk-cgroup cleanups Christoph Hellwig
2020-06-27 7:31 ` [PATCH 01/14] dm: use bio_uninit instead of bio_disassociate_blkg Christoph Hellwig
2020-06-29 9:31 ` Johannes Thumshirn
[not found] ` <20200627073159.2447325-2-hch-jcswGhMUV9g@public.gmane.org>
2020-07-08 14:02 ` Mike Snitzer
[not found] ` <20200627073159.2447325-1-hch-jcswGhMUV9g@public.gmane.org>
2020-06-27 7:31 ` [PATCH 02/14] block: remove bio_disassociate_blkg Christoph Hellwig
2020-06-29 9:33 ` Johannes Thumshirn
2020-06-27 7:31 ` [PATCH 08/14] block: bypass blkg_tryget_closest for the root_blkg Christoph Hellwig
2020-06-27 7:31 ` [PATCH 12/14] blk-cgroup: move rcu locking from blkcg_bio_issue_check to blk_throtl_bio Christoph Hellwig
2020-06-27 7:31 ` [PATCH 03/14] block: really clone the block cgroup in bio_clone_blkg_association Christoph Hellwig
2020-06-29 9:37 ` Johannes Thumshirn
2020-06-27 7:31 ` Christoph Hellwig [this message]
2020-06-29 9:55 ` [PATCH 04/14] block: merge __bio_associate_blkg into bio_associate_blkg_from_css Johannes Thumshirn
2020-06-27 7:31 ` [PATCH 05/14] block: move bio_associate_blkg_from_page to mm/page_io.c Christoph Hellwig
2020-06-29 9:59 ` Johannes Thumshirn
2020-06-29 10:08 ` Johannes Thumshirn
2020-06-27 7:31 ` [PATCH 06/14] block: move the bio cgroup associatation helpers to blk-cgroup.c Christoph Hellwig
2020-06-29 11:51 ` Johannes Thumshirn
2020-06-27 7:31 ` [PATCH 07/14] block: merge blkg_lookup_create and __blkg_lookup_create Christoph Hellwig
2020-06-29 12:21 ` Johannes Thumshirn
2020-06-27 7:31 ` [PATCH 09/14] block: move the initial blkg lookup into blkg_tryget_closest Christoph Hellwig
2020-06-27 7:31 ` [PATCH 10/14] blk-cgroup: remove the !bio->bi_blkg check in blkcg_bio_issue_check Christoph Hellwig
2020-06-27 7:31 ` [PATCH 11/14] cgroup: unexport cgroup_rstat_updated Christoph Hellwig
2020-06-27 7:31 ` [PATCH 13/14] blk-cgroup: remove blkcg_bio_issue_check Christoph Hellwig
2020-06-27 7:31 ` [PATCH 14/14] blk-cgroup: remove a dead check in blk_throtl_bio Christoph Hellwig
2020-06-29 8:05 ` drive-by blk-cgroup cleanups Johannes Thumshirn
2020-06-29 8:08 ` Christoph Hellwig
2020-06-29 8:12 ` Johannes Thumshirn
2020-06-29 13:56 ` Tejun Heo
2020-06-29 15:09 ` Jens Axboe
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