Messages in this thread Patch in this message | | | From | Mel Gorman <> | Subject | [PATCH 03/12] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled | Date | Mon, 24 Aug 2015 13:09:42 +0100 |
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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> --- 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
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