[PATCH] mm: use migrate_prep() instead of migrate_prep_local()

[PATCH] mm: use migrate_prep() instead of migrate_prep_local()

[Marek Szyprowski]

__alloc_contig_migrate_range() should use all possible ways to get all the
pages migrated from the given memory range, so pruning per-cpu lru lists
for all CPUs is required, regadless the cost of such operation. Otherwise
some pages which got stuck at per-cpu lru list might get missed by
migration procedure causing the contiguous allocation to fail.

Reported-by: SeongHwan Yoon <sunghwan.yun@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 mm/page_alloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1bfe2b0..fcb9719 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5677,7 +5677,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
 	unsigned int tries = 0;
 	int ret = 0;
 
-	migrate_prep_local();
+	migrate_prep();
 
 	while (pfn < end || !list_empty(&cc->migratepages)) {
 		if (fatal_signal_pending(current)) {
-- 
1.7.9.5

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Re: [PATCH] mm: use migrate_prep() instead of migrate_prep_local()

[Michal Nazarewicz]

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On Mon, Nov 12 2012, Marek Szyprowski wrote:
> __alloc_contig_migrate_range() should use all possible ways to get all the
> pages migrated from the given memory range, so pruning per-cpu lru lists
> for all CPUs is required, regadless the cost of such operation. Otherwise
> some pages which got stuck at per-cpu lru list might get missed by
> migration procedure causing the contiguous allocation to fail.
>
> Reported-by: SeongHwan Yoon <sunghwan.yun@samsung.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
>  mm/page_alloc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 1bfe2b0..fcb9719 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5677,7 +5677,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
>  	unsigned int tries = 0;
>  	int ret = 0;
>  
> -	migrate_prep_local();
> +	migrate_prep();
>  
>  	while (pfn < end || !list_empty(&cc->migratepages)) {
>  		if (fatal_signal_pending(current)) {

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

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