tree 9a36846301c78c960d569823d468e5b84556e30c
parent a09759acaacf6cf738e1bc6c66d41485c87fd371
author Vlastimil Babka <vbabka@suse.cz> 1487977010 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1487987214 -0800

mm, page_alloc: remove redundant checks from alloc fastpath

The allocation fast path contains two similar checks for zoneref->zone
being NULL, where zoneref points either to the first zone in the
zonelist, or to the preferred zone.  These can be NULL either due to
empty zonelist, or no zone being compatible with given nodemask or
task's cpuset.

These checks are unnecessary, because the zonelist walks in
first_zones_zonelist() and get_page_from_freelist() handle a NULL
starting zoneref->zone or preferred_zoneref->zone safely.  It's safe to
fallback to __alloc_pages_slowpath() where we also have the check early
enough.

Link: http://lkml.kernel.org/r/20170124150511.5710-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>