* [PATCH] mm: delete duplicate order checking, when stealing whole pageblock
@ 2021-06-11 6:38 chengkaitao
2021-06-12 0:00 ` Andrew Morton
0 siblings, 1 reply; 2+ messages in thread
From: chengkaitao @ 2021-06-11 6:38 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, smcdef, chengkaitao
From: chengkaitao <pilgrimtao@gmail.com>
1. Already has (order >= pageblock_order / 2) here, we don't neet
(order >= pageblock_order)
2. set function can_steal_fallback to inline
Signed-off-by: chengkaitao <pilgrimtao@gmail.com>
---
mm/page_alloc.c | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ded02d867491..180081fe711b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2619,18 +2619,8 @@ static void change_pageblock_range(struct page *pageblock_page,
* is worse than movable allocations stealing from unmovable and reclaimable
* pageblocks.
*/
-static bool can_steal_fallback(unsigned int order, int start_mt)
+static inline bool can_steal_fallback(unsigned int order, int start_mt)
{
- /*
- * Leaving this order check is intended, although there is
- * relaxed order check in next check. The reason is that
- * we can actually steal whole pageblock if this condition met,
- * but, below check doesn't guarantee it and that is just heuristic
- * so could be changed anytime.
- */
- if (order >= pageblock_order)
- return true;
-
if (order >= pageblock_order / 2 ||
start_mt == MIGRATE_RECLAIMABLE ||
start_mt == MIGRATE_UNMOVABLE ||
--
2.14.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mm: delete duplicate order checking, when stealing whole pageblock
2021-06-11 6:38 [PATCH] mm: delete duplicate order checking, when stealing whole pageblock chengkaitao
@ 2021-06-12 0:00 ` Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2021-06-12 0:00 UTC (permalink / raw)
To: chengkaitao; +Cc: linux-mm, linux-kernel, smcdef, Joonsoo Kim
On Fri, 11 Jun 2021 14:38:34 +0800 chengkaitao <pilgrimtao@gmail.com> wrote:
> From: chengkaitao <pilgrimtao@gmail.com>
>
> 1. Already has (order >= pageblock_order / 2) here, we don't neet
> (order >= pageblock_order)
> 2. set function can_steal_fallback to inline
>
> ...
>
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2619,18 +2619,8 @@ static void change_pageblock_range(struct page *pageblock_page,
> * is worse than movable allocations stealing from unmovable and reclaimable
> * pageblocks.
> */
> -static bool can_steal_fallback(unsigned int order, int start_mt)
> +static inline bool can_steal_fallback(unsigned int order, int start_mt)
> {
> - /*
> - * Leaving this order check is intended, although there is
> - * relaxed order check in next check. The reason is that
> - * we can actually steal whole pageblock if this condition met,
> - * but, below check doesn't guarantee it and that is just heuristic
> - * so could be changed anytime.
> - */
> - if (order >= pageblock_order)
> - return true;
> -
> if (order >= pageblock_order / 2 ||
> start_mt == MIGRATE_RECLAIMABLE ||
> start_mt == MIGRATE_UNMOVABLE ||
Well, that redundant check was put there deliberately, as the comment
explains.
The reasoning is perhaps a little dubious, but it seems that the
compiler has optimized away the redundant check anyway (your patch
doesn't alter code size).
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-06-11 6:38 [PATCH] mm: delete duplicate order checking, when stealing whole pageblock chengkaitao
2021-06-12 0:00 ` Andrew Morton
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