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authorDavid Rientjes <rientjes@google.com>2014-04-07 15:37:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 16:35:54 -0700
commitf0432d159601f96839f514f286eaa5b75c4112dc (patch)
tree654f94de69e9b7465480172b09e6838f08e81989 /kernel
parent2a389610a7331d22344698f23ef2e8c55b2cde7b (diff)
downloadop-kernel-dev-f0432d159601f96839f514f286eaa5b75c4112dc.zip
op-kernel-dev-f0432d159601f96839f514f286eaa5b75c4112dc.tar.gz
mm, mempolicy: remove per-process flag
PF_MEMPOLICY is an unnecessary optimization for CONFIG_SLAB users. There's no significant performance degradation to checking current->mempolicy rather than current->flags & PF_MEMPOLICY in the allocation path, especially since this is considered unlikely(). Running TCP_RR with netperf-2.4.5 through localhost on 16 cpu machine with 64GB of memory and without a mempolicy: threads before after 16 1249409 1244487 32 1281786 1246783 48 1239175 1239138 64 1244642 1241841 80 1244346 1248918 96 1266436 1254316 112 1307398 1312135 128 1327607 1326502 Per-process flags are a scarce resource so we should free them up whenever possible and make them available. We'll be using it shortly for memcg oom reserves. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Tim Hockin <thockin@google.com> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index c777964..e905e9c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1276,7 +1276,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
p->mempolicy = NULL;
goto bad_fork_cleanup_threadgroup_lock;
}
- mpol_fix_fork_child_flag(p);
#endif
#ifdef CONFIG_CPUSETS
p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
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