The patch titled
Subject: cpumask: don't perform while loop in cpumask_next_and()
has been added to the -mm tree. Its filename is
cpumask-dont-perform-while-loop-in-cpumask_next_and.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/cpumask-dont-perform-while-loop-in-cpumask_next_and.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/cpumask-dont-perform-while-loop-in-cpumask_next_and.patch
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------------------------------------------------------
From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Subject: cpumask: don't perform while loop in cpumask_next_and()
cpumask_next_and() is looking for cpumask_next() in src1 in a loop and
tests if found cpu is also present in src2. remove that loop, perform
cpumask_and() of src1 and src2 first and use that new mask to find
cpumask_next().
Apart from removing while loop, ./bloat-o-meter on x86_64 shows
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-8 (-8)
function old new delta
cpumask_next_and 62 54 -8
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Amir Vadai <amirv@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/cpumask.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff -puN lib/cpumask.c~cpumask-dont-perform-while-loop-in-cpumask_next_and lib/cpumask.c
--- a/lib/cpumask.c~cpumask-dont-perform-while-loop-in-cpumask_next_and
+++ a/lib/cpumask.c
@@ -37,10 +37,11 @@ EXPORT_SYMBOL(__next_cpu_nr);
int cpumask_next_and(int n, const struct cpumask *src1p,
const struct cpumask *src2p)
{
- while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
- if (cpumask_test_cpu(n, src2p))
- break;
- return n;
+ struct cpumask tmp;
+
+ if (cpumask_and(&tmp, src1p, src2p))
+ return cpumask_next(n, &tmp);
+ return nr_cpu_ids;
}
EXPORT_SYMBOL(cpumask_next_and);
_
Patches currently in -mm which might be from sergey.senozhatsky@xxxxxxxxx are
cpumask-dont-perform-while-loop-in-cpumask_next_and.patch
lib-lz4-pull-out-constant-tables.patch
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