lkml.org 
[lkml]   [2013]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 5/7] mm/hwpoison: don't set migration type twice to avoid hold heavy contend zone->lock
On Fri, Aug 23, 2013 at 06:30:39PM +0800, Wanpeng Li wrote:
> v1 -> v2:
> * add more explanation in patch description.
>
> Set pageblock migration type will hold zone->lock which is heavy contended
> in system to avoid race. However, soft offline page will set pageblock
> migration type twice during get page if the page is in used, not hugetlbfs
> page and not on lru list. There is unnecessary to set the pageblock migration
> type and hold heavy contended zone->lock again if the first round get page
> have already set the pageblock to right migration type.
>
> The trick here is migration type is MIGRATE_ISOLATE. There are other two parts
> can change MIGRATE_ISOLATE except hwpoison. One is memory hoplug, however, we
> hold lock_memory_hotplug() which avoid race. The second is CMA which umovable
> page allocation requst can't fallback to. So it's safe here.
>
> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
> ---
> mm/memory-failure.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 297965e..f357c91 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1426,7 +1426,8 @@ static int __get_any_page(struct page *p, unsigned long pfn, int flags)
> * was free. This flag should be kept set until the source page
> * is freed and PG_hwpoison on it is set.
> */
> - set_migratetype_isolate(p, true);
> + if (get_pageblock_migratetype(p) == MIGRATE_ISOLATE)
> + set_migratetype_isolate(p, true);

Do you really mean "we set MIGRATE_ISOLATE only if it's already set?"

Thanks,
Naoya Horiguchi

> /*
> * When the target page is a free hugepage, just remove it
> * from free hugepage list.
> --
> 1.8.1.2
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>


\
 
 \ /
  Last update: 2013-08-23 17:01    [W:0.238 / U:0.288 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site