From: xuw2015@gmail.com
To: xfs@oss.sgi.com
Cc: George Wang <xuw2015@gmail.com>
Subject: [PATCH v2] xfs: use percpu_counter_read_positive for mp->m_icount
Date: Fri, 17 Apr 2015 15:40:23 +0800 [thread overview]
Message-ID: <1429256423-9809-1-git-send-email-xuw2015@gmail.com> (raw)
From: George Wang <xuw2015@gmail.com>
Function percpu_counter_read just return the current counter, which can be
negative. This will cause the checking of "allocated inode
counts <= m_maxicount" false positive. Use percpu_counter_read_positive can
solve this problem, and be consistent with the purpose to introduce percpu
mechanism to xfs.
Signed-off-by: George Wang <xuw2015@gmail.com>
---
fs/xfs/libxfs/xfs_ialloc.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 07349a1..1c9e755 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -376,7 +376,7 @@ xfs_ialloc_ag_alloc(
*/
newlen = args.mp->m_ialloc_inos;
if (args.mp->m_maxicount &&
- percpu_counter_read(&args.mp->m_icount) + newlen >
+ percpu_counter_read_positive(&args.mp->m_icount) + newlen >
args.mp->m_maxicount)
return -ENOSPC;
args.minlen = args.maxlen = args.mp->m_ialloc_blks;
@@ -1339,10 +1339,13 @@ xfs_dialloc(
* If we have already hit the ceiling of inode blocks then clear
* okalloc so we scan all available agi structures for a free
* inode.
+ *
+ * Read rough value of mp->m_icount by percpu_counter_read_positive,
+ * which will sacrifice the preciseness but improve the performance.
*/
if (mp->m_maxicount &&
- percpu_counter_read(&mp->m_icount) + mp->m_ialloc_inos >
- mp->m_maxicount) {
+ percpu_counter_read_positive(&mp->m_icount) + mp->m_ialloc_inos
+ > mp->m_maxicount) {
noroom = 1;
okalloc = 0;
}
--
1.9.3
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
reply other threads:[~2015-04-17 7:40 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=1429256423-9809-1-git-send-email-xuw2015@gmail.com \
--to=xuw2015@gmail.com \
--cc=xfs@oss.sgi.com \
/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