The patch titled
Subject: mm/page_alloc: cache page_zone() result in free_unref_page()
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-cache-page_zone-result-in-free_unref_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-cache-page_zone-result-in-free_unref_page.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm/page_alloc: cache page_zone() result in free_unref_page()
Date: Mon, 25 Nov 2024 21:01:33 +0000
Patch series "Allocate and free frozen pages", v3.
Slab does not need to use the page refcount at all, and it can avoid an
atomic operation on page free. Hugetlb wants to delay setting the
refcount until it has assembled a complete gigantic page. We already have
the ability to freeze a page (safely reduce its reference count to 0), so
this patchset adds APIs to allocate and free pages which are in a frozen
state.
This patchset is also a step towards the Glorious Future in which struct
page doesn't have a refcount; the users which need a refcount will have
one in their per-allocation memdesc.
This patch (of 15):
Save 17 bytes of text by calculating page_zone() once instead of twice.
Link: https://lkml.kernel.org/r/20241125210149.2976098-1-willy@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20241125210149.2976098-2-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: William Kucharski <william.kucharski@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-cache-page_zone-result-in-free_unref_page
+++ a/mm/page_alloc.c
@@ -2664,16 +2664,16 @@ void free_unref_page(struct page *page,
* get those areas back if necessary. Otherwise, we may have to free
* excessively into the page allocator
*/
+ zone = page_zone(page);
migratetype = get_pfnblock_migratetype(page, pfn);
if (unlikely(migratetype >= MIGRATE_PCPTYPES)) {
if (unlikely(is_migrate_isolate(migratetype))) {
- free_one_page(page_zone(page), page, pfn, order, FPI_NONE);
+ free_one_page(zone, page, pfn, order, FPI_NONE);
return;
}
migratetype = MIGRATE_MOVABLE;
}
- zone = page_zone(page);
pcp_trylock_prepare(UP_flags);
pcp = pcp_spin_trylock(zone->per_cpu_pageset);
if (pcp) {
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-page_alloc-cache-page_zone-result-in-free_unref_page.patch
mm-make-alloc_pages_mpol-static.patch
mm-page_alloc-export-free_frozen_pages-instead-of-free_unref_page.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-post_alloc_hook.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-prep_new_page.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-get_page_from_freelist.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_cpuset_fallback.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_may_oom.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_direct_compact.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_direct_reclaim.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_slowpath.patch
mm-page_alloc-move-set_page_refcounted-to-end-of-__alloc_pages.patch
mm-page_alloc-add-__alloc_frozen_pages.patch
mm-mempolicy-add-alloc_frozen_pages.patch
slab-allocate-frozen-pages.patch
