svn commit: r333052 - head/sys/vm

[Mateusz Guzik]

Author: mjg
Date: Fri Apr 27 05:37:35 2018
New Revision: 333052
URL: https://svnweb.freebsd.org/changeset/base/333052

Log:
  uma: whack main zone counter update in the slow path
  
  Cached counters are typically zero at this point so it performs
  avoidable atomics. Everything reading them also reads the cached
  ones, thus there is really no point.
  
  Reviewed by:		jeff

Modified:
  head/sys/vm/uma_core.c

Modified: head/sys/vm/uma_core.c
==============================================================================
--- head/sys/vm/uma_core.c	Fri Apr 27 05:36:02 2018	(r333051)
+++ head/sys/vm/uma_core.c	Fri Apr 27 05:37:35 2018	(r333052)
@@ -2329,14 +2329,6 @@ zalloc_start:
 	cpu = curcpu;
 	cache = &zone->uz_cpu[cpu];
 
-	/*
-	 * Since we have locked the zone we may as well send back our stats.
-	 */
-	atomic_add_long(&zone->uz_allocs, cache->uc_allocs);
-	atomic_add_long(&zone->uz_frees, cache->uc_frees);
-	cache->uc_allocs = 0;
-	cache->uc_frees = 0;
-
 	/* See if we lost the race to fill the cache. */
 	if (cache->uc_allocbucket != NULL) {
 		ZONE_UNLOCK(zone);