The patch titled
Subject: mm/page_alloc: remove unused fpi_flags in free_pages_prepare()
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-remove-unused-fpi_flags-in-free_pages_prepare.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-remove-unused-fpi_flags-in-free_pages_prepare.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: Zi Yan <ziy@xxxxxxxxxx>
Subject: mm/page_alloc: remove unused fpi_flags in free_pages_prepare()
Date: Fri, 16 Feb 2024 12:04:29 -0500
Patch series "Enable >0 order folio memory compaction", v6.
This patchset enables >0 order folio memory compaction, which is one of
the prerequisitions for large folio support[1].
I am aware of that split free pages is necessary for folio migration in
compaction, since if >0 order free pages are never split and no order-0
free page is scanned, compaction will end prematurely due to migration
returns -ENOMEM. Free page split becomes a must instead of an
optimization.
lkp ncompare results (on a 8-CPU (Intel Xeon E5-2650 v4 @2.20GHz) 16G VM)
for default LRU (-no-mglru) and CONFIG_LRU_GEN are shown at the bottom,
copied from V3[4].
In sum, most of vm-scalability applications do not see performance change,
and the others see ~4% to ~26% performance boost under default LRU and ~2%
to ~6% performance boost under CONFIG_LRU_GEN.
To support >0 order folio compaction, the patchset changes how free pages used
for migration are kept during compaction. Free pages used to be split into
order-0 pages that are post allocation processed (i.e., PageBuddy flag cleared,
page order stored in page->private is zeroed, and page reference is set to 1).
Now all free pages are kept in a NR_PAGE_ORDER array of page lists based
on their order without post allocation process. When migrate_pages() asks for
a new page, one of the free pages, based on the requested page order, is
then processed and given out. And THP <2MB would need this feature.
[1] https://lore.kernel.org/linux-mm/f8d47176-03a8-99bf-a813-b5942830fd73@xxxxxxx/
[2] https://lore.kernel.org/linux-mm/20231113170157.280181-1-zi.yan@xxxxxxxx/
[3] https://lore.kernel.org/linux-mm/20240123034636.1095672-1-zi.yan@xxxxxxxx/
[4] https://lore.kernel.org/linux-mm/20240202161554.565023-1-zi.yan@xxxxxxxx/
[5] https://lore.kernel.org/linux-mm/20240212163510.859822-1-zi.yan@xxxxxxxx/
[6] https://lore.kernel.org/linux-mm/20240214220420.1229173-1-zi.yan@xxxxxxxx/
This patch (of 4):
fpi_flags is only passed to should_skip_kasan_poison() but ignored by the
function. Remove the unused parameter.
Link: https://lkml.kernel.org/r/20240216170432.1268753-2-zi.yan@xxxxxxxx
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Adam Manzanares <a.manzanares@xxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Cc: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-remove-unused-fpi_flags-in-free_pages_prepare
+++ a/mm/page_alloc.c
@@ -1061,7 +1061,7 @@ out:
* on-demand allocation and then freed again before the deferred pages
* initialization is done, but this is not likely to happen.
*/
-static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
+static inline bool should_skip_kasan_poison(struct page *page)
{
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
return deferred_pages_enabled();
@@ -1081,10 +1081,10 @@ static void kernel_init_pages(struct pag
}
static __always_inline bool free_pages_prepare(struct page *page,
- unsigned int order, fpi_t fpi_flags)
+ unsigned int order)
{
int bad = 0;
- bool skip_kasan_poison = should_skip_kasan_poison(page, fpi_flags);
+ bool skip_kasan_poison = should_skip_kasan_poison(page);
bool init = want_init_on_free();
bool compound = PageCompound(page);
@@ -1266,7 +1266,7 @@ static void __free_pages_ok(struct page
unsigned long pfn = page_to_pfn(page);
struct zone *zone = page_zone(page);
- if (!free_pages_prepare(page, order, fpi_flags))
+ if (!free_pages_prepare(page, order))
return;
/*
@@ -2343,7 +2343,7 @@ static bool free_unref_page_prepare(stru
{
int migratetype;
- if (!free_pages_prepare(page, order, FPI_NONE))
+ if (!free_pages_prepare(page, order))
return false;
migratetype = get_pfnblock_migratetype(page, pfn);
_
Patches currently in -mm which might be from ziy@xxxxxxxxxx are
mm-page_alloc-remove-unused-fpi_flags-in-free_pages_prepare.patch
mm-compaction-enable-compacting-0-order-folios.patch
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
mm-compaction-optimize-0-order-folio-compaction-with-free-page-split.patch
