Commit 7f822c24 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds

memcg: drop unnecessary cold-path tests from __memcg_kmem_bypass()

__memcg_kmem_bypass() decides whether a kmem allocation should be bypassed
to the root memcg.  Some conditions that it tests are valid criteria
regarding who should be held accountable; however, there are a couple
unnecessary tests for cold paths - __GFP_FAIL and fatal_signal_pending().

The previous patch updated try_charge() to handle both __GFP_FAIL and
dying tasks correctly and the only thing these two tests are doing is
making accounting less accurate and sprinkling tests for cold path
conditions in the hot paths.  There's nothing meaningful gained by these
extra tests.

This patch removes the two unnecessary tests from __memcg_kmem_bypass().
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 10d53c74
...@@ -781,24 +781,10 @@ static inline bool __memcg_kmem_bypass(gfp_t gfp) ...@@ -781,24 +781,10 @@ static inline bool __memcg_kmem_bypass(gfp_t gfp)
{ {
if (!memcg_kmem_enabled()) if (!memcg_kmem_enabled())
return true; return true;
if (gfp & __GFP_NOACCOUNT) if (gfp & __GFP_NOACCOUNT)
return true; return true;
/*
* __GFP_NOFAIL allocations will move on even if charging is not
* possible. Therefore we don't even try, and have this allocation
* unaccounted. We could in theory charge it forcibly, but we hope
* those allocations are rare, and won't be worth the trouble.
*/
if (gfp & __GFP_NOFAIL)
return true;
if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD)) if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
return true; return true;
/* If the test is dying, just let it go. */
if (unlikely(fatal_signal_pending(current)))
return true;
return false; return false;
} }
......
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