Re: Kswapd in 3.2.0-rc5 is a CPU hog

From: Hillf Danton
Date: Mon Dec 26 2011 - 07:35:46 EST


On Sun, Dec 25, 2011 at 6:21 PM, Nikolay S. <nowhere@xxxxxxxxxxxxxxxx> wrote:
>
> Uhm.., is this patch against 3.2-rc4? I can not apply it. There's no
> mem_cgroup_lru_del_list(), but void mem_cgroup_del_lru_list(). Should I
> place changes there?
>
> And also, -rc7 is here. May the problem be addressed as part of some
> ongoing work? Is there any reason to try -rc7 (the problem requires
> several days of uptime to become obvious)?
>

Sorry, Nikolay, it is not based on the -next, nor on the -rc5(I assumed it was).
The following is based on -next, and if you want to test -rc5, please
grep MEM_CGROUP_ZSTAT mm/memcontrol.c and change it.

Best regard

Hillf
---

--- a/mm/memcontrol.c Mon Dec 26 20:34:38 2011
+++ b/mm/memcontrol.c Mon Dec 26 20:37:54 2011
@@ -1076,7 +1076,11 @@ void mem_cgroup_lru_del_list(struct page
VM_BUG_ON(!memcg);
mz = page_cgroup_zoneinfo(memcg, page);
/* huge page split is done under lru_lock. so, we have no races. */
- MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
+ if (WARN_ON_ONCE(MEM_CGROUP_ZSTAT(mz, lru) <
+ (1 << compound_order(page))))
+ MEM_CGROUP_ZSTAT(mz, lru) = 0;
+ else
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
}

void mem_cgroup_lru_del(struct page *page)
--
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