• David Rientjes's avatar
    mm, mempolicy: remove per-process flag · f0432d15
    David Rientjes authored
    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: default avatarDavid 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    f0432d15
slab.c 110 KB