* [PATCHv2] mm: No need to check pcp page when free it to buddy
@ 2022-09-15 2:40 zhaoyang.huang
2022-09-15 22:05 ` Andrew Morton
0 siblings, 1 reply; 2+ messages in thread
From: zhaoyang.huang @ 2022-09-15 2:40 UTC (permalink / raw)
To: Andrew Morton, Zhaoyang Huang, linux-mm, linux-kernel, ke.wang
From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
The pages on pcp list have been checked the validity via bellowing call chain.
It is no need to check it again when free them back to buddy by free_pcppages_bulk.
free_unref_page\free_unref_page_list
{
...
//page's validity is checked here
if (!free_unref_page_prepare(page, pfn, order))
return;
...
//page added to pcp->lists and status is ready for moving to buddy
list_add(&page->lru, &pcp->lists[pindex]);
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
v2: update code and comment for clarifying
---
---
mm/page_alloc.c | 16 ----------------
1 file changed, 16 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e008a3d..1472ebc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1420,14 +1420,6 @@ static bool free_pcp_prepare(struct page *page, unsigned int order)
{
return free_pages_prepare(page, order, true, FPI_NONE);
}
-
-static bool bulkfree_pcp_prepare(struct page *page)
-{
- if (debug_pagealloc_enabled_static())
- return check_free_page(page);
- else
- return false;
-}
#else
/*
* With DEBUG_VM disabled, order-0 pages being freed are checked only when
@@ -1442,11 +1434,6 @@ static bool free_pcp_prepare(struct page *page, unsigned int order)
else
return free_pages_prepare(page, order, false, FPI_NONE);
}
-
-static bool bulkfree_pcp_prepare(struct page *page)
-{
- return check_free_page(page);
-}
#endif /* CONFIG_DEBUG_VM */
/*
@@ -1512,9 +1499,6 @@ static void free_pcppages_bulk(struct zone *zone, int count,
count -= nr_pages;
pcp->count -= nr_pages;
- if (bulkfree_pcp_prepare(page))
- continue;
-
/* MIGRATE_ISOLATE page should not go to pcplists */
VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
/* Pageblock could have been isolated meanwhile */
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCHv2] mm: No need to check pcp page when free it to buddy
2022-09-15 2:40 [PATCHv2] mm: No need to check pcp page when free it to buddy zhaoyang.huang
@ 2022-09-15 22:05 ` Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2022-09-15 22:05 UTC (permalink / raw)
To: zhaoyang.huang; +Cc: Zhaoyang Huang, linux-mm, linux-kernel, ke.wang
On Thu, 15 Sep 2022 10:40:54 +0800 "zhaoyang.huang" <zhaoyang.huang@unisoc.com> wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> The pages on pcp list have been checked the validity via bellowing call chain.
> It is no need to check it again when free them back to buddy by free_pcppages_bulk.
>
> free_unref_page\free_unref_page_list
> {
> ...
> //page's validity is checked here
> if (!free_unref_page_prepare(page, pfn, order))
> return;
> ...
> //page added to pcp->lists and status is ready for moving to buddy
> list_add(&page->lru, &pcp->lists[pindex]);
>
The comment over free_pcp_prepare():
/*
* With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
* to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
* moved from pcp lists to free lists.
*/
Which seems sensible - a page's state may have been messed up while
it's in the pcp lists.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-09-15 22:05 ` Andrew Morton
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