OpenVZ Forum


Home » Mailing lists » Devel » [RFC][ only for review ] memory controller bacground reclaim [0/5]
Re: [RFC][ only for review ] memory controller bacground reclaim [0/5] (Does anyone have an idea abo [message #23964 is a reply to message #23861] Thu, 29 November 2007 11:53 Go to previous messageGo to previous message
KAMEZAWA Hiroyuki is currently offline  KAMEZAWA Hiroyuki
Messages: 463
Registered: September 2006
Senior Member
On Wed, 28 Nov 2007 17:49:23 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> Hi, this set is for memory controller background reclaim.
> 
> Merged YAMAMOTO-san's version onto 2.6.23-rc3-mm1 + my NUMA patch.
> And splitted to several sets.
> 
> Major changes from his one is
>  - use kthread instead of work_queue
>  - adjust high/low watermark when limit changes automatically
>    and set default value. (a user can specify his own later.)
> 
FYI rather than RFC.

I wrote attached patch and run kernbench on 8CPU/2Node NUMA/ia64.
It does make -j 32.

Memory limitation was 800M. Low/High watermark here was 750M/780M.

== These numbers are stable to some extent.==
2.6.24-rc3-mm2: (Limit: 800M)     
Average Optimal -j 32 Load Run:
Elapsed Time 358.933---------------------------(*)
User Time 1069.63
System Time 140.667
Percent CPU 337.333
Context Switches 220821
Sleeps 196912

2.6.24-rc3-mm2 + throttle (Limit:800M)
Average Optimal -j 32 Load Run:
Elapsed Time 266.697---------------------------(*)
User Time 1105.39
System Time 124.423
Percent CPU 471.667
Context Switches 251797
Sleeps 231038

2.6.24-rc3-mm2 + throttle + High/Low watermark.
(low:750M High:780M Limit:800M)
Average Optimal -j 32 Load Run:
Elapsed Time 266.844---------------------------(*)
User Time 1112.9
System Time 112.273
Percent CPU 473.667
Context Switches 251795
Sleeps 220339
==

Seems throttling reclaim has some good effect (for kernbench).
Does anyone have an idea for throttling  reclaiming of memory controller ?

Thanks,
-Kame
==
Just and Experimental. add throttling at starting direct reclaim.


 mm/memcontrol.c |   22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

Index: linux-2.6.24-rc3-mm2/mm/memcontrol.c
===================================================================
--- linux-2.6.24-rc3-mm2.orig/mm/memcontrol.c
+++ linux-2.6.24-rc3-mm2/mm/memcontrol.c
@@ -133,6 +133,7 @@ struct mem_cgroup {
 
 	unsigned long control_type;	/* control RSS or RSS+Pagecache */
 	int	prev_priority;	/* for recording reclaim priority */
+	atomic_t	reclaimers; /* # of processes which calls reclaim */
 	/*
 	 * statistics.
 	 */
@@ -635,14 +636,27 @@ retry:
 	 */
 	while (res_counter_charge(&mem->res, PAGE_SIZE)) {
 		bool is_atomic = gfp_mask & GFP_ATOMIC;
+		int limit;
 		/*
 		 * We cannot reclaim under GFP_ATOMIC, fail the charge
 		 */
 		if (is_atomic)
 			goto noreclaim;
-
-		if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
-			continue;
+		/*
+		 * Experimental: 
+		 * Obviously, we need some throttling here.
+		 */
+		limit = num_online_cpus()/4 + 1;
+		if (atomic_add_unless(&mem->reclaimers, 1, limit)) {
+			if (try_to_free_mem_cgroup_pages(mem, gfp_mask)) {
+				atomic_dec(&mem->reclaimers);
+				continue;
+			}
+			atomic_dec(&mem->reclaimers);
+		} else {
+			yield();
+			nr_retries++;
+		}
 
 		/*
  		 * try_to_free_mem_cgroup_pages() might not give us a full
@@ -1168,7 +1182,7 @@ mem_cgroup_create(struct cgroup_subsys *
 
 	mem->control_type = MEM_CGROUP_TYPE_ALL;
 	memset(&mem->info, 0, sizeof(mem->info));
-
+	atomic_set(&mem->reclaimers, 0);
 	for_each_node_state(node, N_POSSIBLE)
 		if (alloc_mem_cgroup_per_zone_info(mem, node))
 			goto free_out;





_______________________________________________
Containers mailing list
Containers@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/containers
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: [PATCH net-2.6.25 2/3][IPV6] Unify and cleanup calls to addrconf_sysctl_register
Next Topic: [PATCH 0/4 net-2.6.15][UNIX] Make unix sysctls per-namespace
Goto Forum:
  


Current Time: Sun Feb 25 16:03:39 GMT 2024

Total time taken to generate the page: 0.03326 seconds