From: NeilBrown <neilb@suse.com>
To: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org, hch@lst.de
Subject: Improvement for [md PATCH 15/15] MD: use per-cpu counter for writes_pending
Date: Wed, 22 Mar 2017 12:55:13 +1100 [thread overview]
Message-ID: <87lgryaxdq.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <148954711465.18641.8222940807591984069.stgit@noble>
[-- Attachment #1: Type: text/plain, Size: 1307 bytes --]
__ref_is_percpu() is documented as an internal interface,
so best not to use it.
We don't really need it, as ->sync_checkers is always 0
when the writes_pending is in per-cpu mode.
So change to test ->sync_checkers, and update comments to match.
Signed-off-by: NeilBrown <neilb@suse.com>
---
drivers/md/md.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index adf2b5bdfd67..b76ac563115e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2266,8 +2266,8 @@ static bool set_in_sync(struct mddev *mddev)
percpu_ref_is_zero(&mddev->writes_pending)) {
mddev->in_sync = 1;
/*
- * Ensure in_sync is visible before switch back
- * to percpu
+ * Ensure ->in_sync is visible before we clear
+ * ->sync_checkers.
*/
smp_mb();
set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
@@ -7920,7 +7920,7 @@ void md_write_start(struct mddev *mddev, struct bio *bi)
smp_mb(); /* Match smp_mb in set_in_sync() */
if (mddev->safemode == 1)
mddev->safemode = 0;
- if (mddev->in_sync || !__ref_is_percpu(&mddev->writes_pending, ¬used)) {
+ if (mddev->in_sync || !mddev->sync_checkers) {
spin_lock(&mddev->lock);
if (mddev->in_sync) {
mddev->in_sync = 0;
--
2.12.0
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]
next prev parent reply other threads:[~2017-03-22 1:55 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 3:05 [md PATCH 00/15 v2] remove all abuse of bi_phys_segments NeilBrown
2017-03-15 3:05 ` [md PATCH 01/15] md/raid5: use md_write_start to count stripes, not bios NeilBrown
2017-03-15 3:05 ` [md PATCH 04/15] block: trace completion of all bios NeilBrown
2017-03-15 3:05 ` [md PATCH 03/15] md/raid5: call bio_endio() directly rather than queueing for later NeilBrown
2017-03-15 3:05 ` [md PATCH 02/15] md/raid5: simplfy delaying of writes while metadata is updated NeilBrown
2017-03-15 23:03 ` Shaohua Li
2017-03-16 2:45 ` NeilBrown
2017-03-22 1:40 ` Fix bug in " NeilBrown
2017-03-22 2:29 ` REALLY " NeilBrown
2017-03-22 2:35 ` NeilBrown
2017-03-23 2:22 ` Shaohua Li
2017-03-15 3:05 ` [md PATCH 06/15] md/raid5: remove over-loading of ->bi_phys_segments NeilBrown
2017-03-15 3:05 ` [md PATCH 09/15] md/raid10: stop using bi_phys_segments NeilBrown
2017-03-15 3:05 ` [md PATCH 08/15] md/raid1, raid10: move rXbio accounting closer to allocation NeilBrown
2017-03-15 3:05 ` [md PATCH 05/15] md/raid5: use bio_inc_remaining() instead of repurposing bi_phys_segments as a counter NeilBrown
2017-03-15 3:05 ` [md PATCH 07/15] Revert "md/raid5: limit request size according to implementation limits" NeilBrown
2017-03-15 3:05 ` [md PATCH 13/15] md: close a race with setting mddev->in_sync NeilBrown
2017-03-15 3:05 ` [md PATCH 10/15] md/raid1: stop using bi_phys_segment NeilBrown
2017-03-16 0:13 ` Shaohua Li
2017-03-16 2:49 ` NeilBrown
2017-03-16 3:36 ` Shaohua Li
2017-03-22 1:41 ` Fix bugs in " NeilBrown
2017-03-15 3:05 ` [md PATCH 12/15] md: factor out set_in_sync() NeilBrown
2017-03-15 3:05 ` [md PATCH 14/15] percpu-refcount: support synchronous switch to atomic mode NeilBrown
2017-03-15 3:05 ` [md PATCH 11/15] md/raid5: don't test ->writes_pending in raid5_remove_disk NeilBrown
2017-03-15 3:05 ` [md PATCH 15/15] MD: use per-cpu counter for writes_pending NeilBrown
2017-03-16 1:05 ` Shaohua Li
2017-03-16 2:57 ` NeilBrown
2017-03-22 1:55 ` NeilBrown [this message]
2017-03-22 2:34 ` IMPROVEMENT for Improvement for " NeilBrown
2017-03-16 1:12 ` [md PATCH 00/15 v2] remove all abuse of bi_phys_segments Shaohua Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87lgryaxdq.fsf@notabene.neil.brown.name \
--to=neilb@suse.com \
--cc=hch@lst.de \
--cc=linux-raid@vger.kernel.org \
--cc=shli@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).