* [PATCH 1/1] mm/page_alloc: merge two get_pfnblock_migratetype() into one
@ 2022-11-23 13:40 wonder_rock
2022-11-23 15:45 ` Matthew Wilcox
0 siblings, 1 reply; 2+ messages in thread
From: wonder_rock @ 2022-11-23 13:40 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, Deyan Wang
From: Deyan Wang <wonder_rock@126.com>
It is safe to get_pfnblock_migratetype() in critical section,
so just call get_pfnblock_migratetype() once.
Signed-off-by: Deyan Wang <wonder_rock@126.com>
---
mm/page_alloc.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6652df1f5cc8..c7ba9d65d1c0 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1704,13 +1704,8 @@ static void __free_pages_ok(struct page *page, unsigned int order,
if (!free_pages_prepare(page, order, true, fpi_flags))
return;
- migratetype = get_pfnblock_migratetype(page, pfn);
-
spin_lock_irqsave(&zone->lock, flags);
- if (unlikely(has_isolate_pageblock(zone) ||
- is_migrate_isolate(migratetype))) {
- migratetype = get_pfnblock_migratetype(page, pfn);
- }
+ migratetype = get_pfnblock_migratetype(page, pfn);
__free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
spin_unlock_irqrestore(&zone->lock, flags);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH 1/1] mm/page_alloc: merge two get_pfnblock_migratetype() into one
2022-11-23 13:40 [PATCH 1/1] mm/page_alloc: merge two get_pfnblock_migratetype() into one wonder_rock
@ 2022-11-23 15:45 ` Matthew Wilcox
0 siblings, 0 replies; 2+ messages in thread
From: Matthew Wilcox @ 2022-11-23 15:45 UTC (permalink / raw)
To: wonder_rock; +Cc: akpm, linux-mm, linux-kernel
On Wed, Nov 23, 2022 at 09:40:43PM +0800, wonder_rock@126.com wrote:
> From: Deyan Wang <wonder_rock@126.com>
>
> It is safe to get_pfnblock_migratetype() in critical section,
> so just call get_pfnblock_migratetype() once.
No, you don't understand. zone->lock is HOT and we want to avoid
calling get_pfnblock_migratetype() under the lock, if we can avoid it.
Which we usually can.
> Signed-off-by: Deyan Wang <wonder_rock@126.com>
> ---
> mm/page_alloc.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 6652df1f5cc8..c7ba9d65d1c0 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1704,13 +1704,8 @@ static void __free_pages_ok(struct page *page, unsigned int order,
> if (!free_pages_prepare(page, order, true, fpi_flags))
> return;
>
> - migratetype = get_pfnblock_migratetype(page, pfn);
> -
> spin_lock_irqsave(&zone->lock, flags);
> - if (unlikely(has_isolate_pageblock(zone) ||
> - is_migrate_isolate(migratetype))) {
> - migratetype = get_pfnblock_migratetype(page, pfn);
> - }
> + migratetype = get_pfnblock_migratetype(page, pfn);
> __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
> spin_unlock_irqrestore(&zone->lock, flags);
>
> --
> 2.25.1
>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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