* [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node()
@ 2016-09-20 6:54 zhongjiang
2016-09-20 20:35 ` Hugh Dickins
2016-09-20 21:06 ` Andrew Morton
0 siblings, 2 replies; 4+ messages in thread
From: zhongjiang @ 2016-09-20 6:54 UTC (permalink / raw)
To: hughd, akpm, mhocko, vbabka, rientjes; +Cc: linux-mm
From: zhong jiang <zhongjiang@huawei.com>
Accoding to HUgh's suggestion, alloc_stable_node() with GFP_KERNEL
will cause the hungtask, despite less possiblity.
At present, if alloc_stable_node allocate fails, two break_cow may
want to allocate a couple of pages, and the issue will come up when
free memory is under pressure.
we fix it by adding the __GFP_HIGH to GFP. because it grant access to
some of meory reserves. it will make progess to make it allocation
successful at the utmost.
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
---
mm/ksm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/ksm.c b/mm/ksm.c
index 5048083..42bf16e 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -299,7 +299,7 @@ static inline void free_rmap_item(struct rmap_item *rmap_item)
static inline struct stable_node *alloc_stable_node(void)
{
- return kmem_cache_alloc(stable_node_cache, GFP_KERNEL);
+ return kmem_cache_alloc(stable_node_cache, GFP_KERNEL | __GFP_HIGH);
}
static inline void free_stable_node(struct stable_node *stable_node)
--
1.8.3.1
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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node()
2016-09-20 6:54 [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node() zhongjiang
@ 2016-09-20 20:35 ` Hugh Dickins
2016-09-20 21:06 ` Andrew Morton
1 sibling, 0 replies; 4+ messages in thread
From: Hugh Dickins @ 2016-09-20 20:35 UTC (permalink / raw)
To: zhongjiang; +Cc: hughd, akpm, mhocko, vbabka, rientjes, linux-mm
On Tue, 20 Sep 2016, zhongjiang wrote:
> From: zhong jiang <zhongjiang@huawei.com>
>
> Accoding to HUgh's suggestion, alloc_stable_node() with GFP_KERNEL
> will cause the hungtask, despite less possiblity.
>
> At present, if alloc_stable_node allocate fails, two break_cow may
> want to allocate a couple of pages, and the issue will come up when
> free memory is under pressure.
>
> we fix it by adding the __GFP_HIGH to GFP. because it grant access to
> some of meory reserves. it will make progess to make it allocation
> successful at the utmost.
>
> Suggested-by: Hugh Dickins <hughd@google.com>
> Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Thanks,
Acked-by: Hugh Dickins <hughd@google.com>
> ---
> mm/ksm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 5048083..42bf16e 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -299,7 +299,7 @@ static inline void free_rmap_item(struct rmap_item *rmap_item)
>
> static inline struct stable_node *alloc_stable_node(void)
> {
> - return kmem_cache_alloc(stable_node_cache, GFP_KERNEL);
> + return kmem_cache_alloc(stable_node_cache, GFP_KERNEL | __GFP_HIGH);
> }
>
> static inline void free_stable_node(struct stable_node *stable_node)
> --
> 1.8.3.1
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node()
2016-09-20 6:54 [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node() zhongjiang
2016-09-20 20:35 ` Hugh Dickins
@ 2016-09-20 21:06 ` Andrew Morton
2016-09-28 2:38 ` zhong jiang
1 sibling, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2016-09-20 21:06 UTC (permalink / raw)
To: zhongjiang; +Cc: hughd, mhocko, vbabka, rientjes, linux-mm
On Tue, 20 Sep 2016 14:54:44 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
> From: zhong jiang <zhongjiang@huawei.com>
>
> Accoding to HUgh's suggestion, alloc_stable_node() with GFP_KERNEL
> will cause the hungtask, despite less possiblity.
>
> At present, if alloc_stable_node allocate fails, two break_cow may
> want to allocate a couple of pages, and the issue will come up when
> free memory is under pressure.
>
> we fix it by adding the __GFP_HIGH to GFP. because it grant access to
> some of meory reserves. it will make progess to make it allocation
> successful at the utmost.
>
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -299,7 +299,7 @@ static inline void free_rmap_item(struct rmap_item *rmap_item)
>
> static inline struct stable_node *alloc_stable_node(void)
> {
> - return kmem_cache_alloc(stable_node_cache, GFP_KERNEL);
> + return kmem_cache_alloc(stable_node_cache, GFP_KERNEL | __GFP_HIGH);
> }
>
> static inline void free_stable_node(struct stable_node *stable_node)
It is very hard for a reader to understand why this __GFP_HIGH is being
used here, so we should have a code comment explaining the reasoning,
please.
--
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node()
2016-09-20 21:06 ` Andrew Morton
@ 2016-09-28 2:38 ` zhong jiang
0 siblings, 0 replies; 4+ messages in thread
From: zhong jiang @ 2016-09-28 2:38 UTC (permalink / raw)
To: Andrew Morton; +Cc: hughd, mhocko, vbabka, rientjes, linux-mm
On 2016/9/21 5:06, Andrew Morton wrote:
> On Tue, 20 Sep 2016 14:54:44 +0800 zhongjiang <zhongjiang@huawei.com> wrote:
>
>> From: zhong jiang <zhongjiang@huawei.com>
>>
>> Accoding to HUgh's suggestion, alloc_stable_node() with GFP_KERNEL
>> will cause the hungtask, despite less possiblity.
>>
>> At present, if alloc_stable_node allocate fails, two break_cow may
>> want to allocate a couple of pages, and the issue will come up when
>> free memory is under pressure.
>>
>> we fix it by adding the __GFP_HIGH to GFP. because it grant access to
>> some of meory reserves. it will make progess to make it allocation
>> successful at the utmost.
>>
>> --- a/mm/ksm.c
>> +++ b/mm/ksm.c
>> @@ -299,7 +299,7 @@ static inline void free_rmap_item(struct rmap_item *rmap_item)
>>
>> static inline struct stable_node *alloc_stable_node(void)
>> {
>> - return kmem_cache_alloc(stable_node_cache, GFP_KERNEL);
>> + return kmem_cache_alloc(stable_node_cache, GFP_KERNEL | __GFP_HIGH);
>> }
>>
>> static inline void free_stable_node(struct stable_node *stable_node)
> It is very hard for a reader to understand why this __GFP_HIGH is being
> used here, so we should have a code comment explaining the reasoning,
> please.
ok, I will add some code comment later.
> --
> 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/ .
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>
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-09-20 6:54 [PATCH] mm,ksm: add __GFP_HIGH to the allocation in alloc_stable_node() zhongjiang
2016-09-20 20:35 ` Hugh Dickins
2016-09-20 21:06 ` Andrew Morton
2016-09-28 2:38 ` zhong jiang
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