From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Michal Hocko <mhocko@kernel.org>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 03/10] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled
Date: Mon, 21 Sep 2015 11:52:35 +0100 [thread overview]
Message-ID: <1442832762-7247-4-git-send-email-mgorman@techsingularity.net> (raw)
In-Reply-To: <1442832762-7247-1-git-send-email-mgorman@techsingularity.net>
There is a seqcounter that protects against spurious allocation failures
when a task is changing the allowed nodes in a cpuset. There is no need
to check the seqcounter until a cpuset exists.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
---
include/linux/cpuset.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 1b357997cac5..6eb27cb480b7 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -104,6 +104,9 @@ extern void cpuset_print_task_mems_allowed(struct task_struct *p);
*/
static inline unsigned int read_mems_allowed_begin(void)
{
+ if (!cpusets_enabled())
+ return 0;
+
return read_seqcount_begin(¤t->mems_allowed_seq);
}
@@ -115,6 +118,9 @@ static inline unsigned int read_mems_allowed_begin(void)
*/
static inline bool read_mems_allowed_retry(unsigned int seq)
{
+ if (!cpusets_enabled())
+ return false;
+
return read_seqcount_retry(¤t->mems_allowed_seq, seq);
}
--
2.4.6
next prev parent reply other threads:[~2015-09-21 10:54 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-21 10:52 [PATCH 00/10] Remove zonelist cache and high-order watermark checking v4 Mel Gorman
2015-09-21 10:52 ` [PATCH 01/10] mm, page_alloc: Remove unnecessary parameter from zone_watermark_ok_safe Mel Gorman
2015-09-24 20:01 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 02/10] mm, page_alloc: Remove unnecessary recalculations for dirty zone balancing Mel Gorman
2015-09-24 20:05 ` Johannes Weiner
2015-09-21 10:52 ` Mel Gorman [this message]
2015-09-24 20:06 ` [PATCH 03/10] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled Johannes Weiner
2015-09-30 22:22 ` David Rientjes
2015-10-01 7:35 ` Vlastimil Babka
2015-09-21 10:52 ` [PATCH 04/10] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types Mel Gorman
2015-09-24 20:34 ` Johannes Weiner
2015-09-25 12:50 ` Mel Gorman
2015-09-25 13:56 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 05/10] mm, page_alloc: Distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd Mel Gorman
2015-09-24 13:51 ` Michal Hocko
2015-09-24 20:55 ` Johannes Weiner
2015-09-25 12:51 ` Mel Gorman
2015-09-25 19:01 ` Johannes Weiner
2015-09-29 13:35 ` Mel Gorman
2015-09-30 12:26 ` Vlastimil Babka
2015-09-30 13:17 ` Mel Gorman
2015-10-01 3:04 ` Drokin, Oleg
2015-10-02 12:30 ` Mel Gorman
2015-09-21 10:52 ` [PATCH 06/10] mm, page_alloc: Rename __GFP_WAIT to __GFP_RECLAIM Mel Gorman
2015-09-25 19:03 ` Johannes Weiner
2015-09-28 23:55 ` Andrew Morton
2015-09-29 13:37 ` Mel Gorman
2015-10-01 8:39 ` Vlastimil Babka
2015-10-02 13:03 ` [PATCH] mm: page_alloc: Hide some GFP internals and document the bits and flag combinations -fix Mel Gorman
2015-10-01 14:06 ` [PATCH 06/10] mm, page_alloc: Rename __GFP_WAIT to __GFP_RECLAIM Michal Hocko
2015-09-30 22:25 ` David Rientjes
2015-09-21 10:52 ` [PATCH 07/10] mm, page_alloc: Delete the zonelist_cache Mel Gorman
2015-09-25 19:09 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 08/10] mm, page_alloc: Remove MIGRATE_RESERVE Mel Gorman
2015-09-21 10:52 ` [PATCH 09/10] mm, page_alloc: Reserve pageblocks for high-order atomic allocations on demand Mel Gorman
2015-09-24 13:50 ` Michal Hocko
2015-09-25 19:22 ` Johannes Weiner
2015-09-29 21:01 ` Andrew Morton
2015-09-30 8:27 ` Mel Gorman
2015-09-30 14:02 ` Vlastimil Babka
2015-09-21 12:03 ` [PATCH 10/10] mm, page_alloc: Only enforce watermarks for order-0 allocations Mel Gorman
2015-09-25 19:32 ` Johannes Weiner
2015-09-29 21:05 ` Andrew Morton
2015-09-30 8:46 ` Mel Gorman
2015-09-30 14:17 ` Vlastimil Babka
2015-09-30 15:12 ` Mel Gorman
2015-09-30 20:37 ` Andrew Morton
2015-09-30 14:11 ` Vlastimil Babka
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=1442832762-7247-4-git-send-email-mgorman@techsingularity.net \
--to=mgorman@techsingularity.net \
--cc=akpm@linux-foundation.org \
--cc=hannes@cmpxchg.org \
--cc=iamjoonsoo.kim@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=riel@redhat.com \
--cc=rientjes@google.com \
--cc=vbabka@suse.cz \
/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).