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mm/page_isolation: make page isolation a standalone bit

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During page isolation, the original migratetype is overwritten, since
MIGRATE_* are enums and stored in pageblock bitmaps.  Change
MIGRATE_ISOLATE to be stored a standalone bit, PB_migrate_isolate, like
PB_compact_skip, so that migratetype is not lost during pageblock
isolation.

Link: https://lkml.kernel.org/r/20250617021115.2331563-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Richard Chang <richardycc@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zi Yan 2025-06-16 22:11:10 -04:00 committed by Andrew Morton
parent 42f46ed99a
commit e904bce2d9
4 changed files with 57 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
include/linux/mmzone.h
View file

@ -79,6 +79,9 @@ enum migratetype {
* __free_pageblock_cma() function.
*/
MIGRATE_CMA,
__MIGRATE_TYPE_END = MIGRATE_CMA,
#else
__MIGRATE_TYPE_END = MIGRATE_HIGHATOMIC,
#endif
#ifdef CONFIG_MEMORY_ISOLATION
MIGRATE_ISOLATE, /* can't allocate from here */

16
include/linux/page-isolation.h
View file

@ -11,6 +11,12 @@ static inline bool is_migrate_isolate(int migratetype)
{
return migratetype == MIGRATE_ISOLATE;
}
#define get_pageblock_isolate(page) \
get_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate)
#define clear_pageblock_isolate(page) \
clear_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate)
#define set_pageblock_isolate(page) \
set_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate)
#else
static inline bool is_migrate_isolate_page(struct page *page)
{
@ -20,6 +26,16 @@ static inline bool is_migrate_isolate(int migratetype)
{
return false;
}
static inline bool get_pageblock_isolate(struct page *page)
{
return false;
}
static inline void clear_pageblock_isolate(struct page *page)
{
}
static inline void set_pageblock_isolate(struct page *page)
{
}
#endif
#define MEMORY_OFFLINE 0x1

14
include/linux/pageblock-flags.h
View file

@ -21,6 +21,13 @@ enum pageblock_bits {
/* 3 bits required for migrate types */
PB_compact_skip,/* If set the block is skipped by compaction */
#ifdef CONFIG_MEMORY_ISOLATION
/*
* Pageblock isolation is represented with a separate bit, so that
* the migratetype of a block is not overwritten by isolation.
*/
PB_migrate_isolate, /* If set the block is isolated */
#endif
/*
* Assume the bits will always align on a word. If this assumption
* changes then get/set pageblock needs updating.
@ -32,6 +39,13 @@ enum pageblock_bits {
#define MIGRATETYPE_MASK ((1UL << (PB_migrate_end + 1)) - 1)
#ifdef CONFIG_MEMORY_ISOLATION
#define MIGRATETYPE_AND_ISO_MASK \
(((1UL << (PB_migrate_end + 1)) - 1) | BIT(PB_migrate_isolate))
#else
#define MIGRATETYPE_AND_ISO_MASK MIGRATETYPE_MASK
#endif
#if defined(CONFIG_HUGETLB_PAGE)
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE

27
mm/page_alloc.c
View file

@ -365,8 +365,12 @@ get_pfnblock_bitmap_bitidx(const struct page *page, unsigned long pfn,
unsigned long *bitmap;
unsigned long word_bitidx;
#ifdef CONFIG_MEMORY_ISOLATION
BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 8);
#else
BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
#endif
BUILD_BUG_ON(__MIGRATE_TYPE_END >= (1 << PB_migratetype_bits));
VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
bitmap = get_pageblock_bitmap(page, pfn);
@ -439,7 +443,16 @@ bool get_pfnblock_bit(const struct page *page, unsigned long pfn,
__always_inline enum migratetype
get_pfnblock_migratetype(const struct page *page, unsigned long pfn)
{
return __get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK);
unsigned long mask = MIGRATETYPE_AND_ISO_MASK;
unsigned long flags;
flags = __get_pfnblock_flags_mask(page, pfn, mask);
#ifdef CONFIG_MEMORY_ISOLATION
if (flags & BIT(PB_migrate_isolate))
return MIGRATE_ISOLATE;
#endif
return flags & MIGRATETYPE_MASK;
}
/**
@ -519,8 +532,16 @@ __always_inline void set_pageblock_migratetype(struct page *page,
migratetype < MIGRATE_PCPTYPES))
migratetype = MIGRATE_UNMOVABLE;
#ifdef CONFIG_MEMORY_ISOLATION
if (migratetype == MIGRATE_ISOLATE) {
set_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate);
return;
}
/* MIGRATETYPE_AND_ISO_MASK clears PB_migrate_isolate if it is set */
#endif
__set_pfnblock_flags_mask(page, page_to_pfn(page),
(unsigned long)migratetype, MIGRATETYPE_MASK);
(unsigned long)migratetype,
MIGRATETYPE_AND_ISO_MASK);
}
#ifdef CONFIG_DEBUG_VM