* [Patch v3 1/2] mm/page_alloc: use xxx_pageblock_isolate() for better reading
2025-08-27 7:01 [Patch v3 0/2] mm/pageblock: improve readability of some pageblock handling Wei Yang
@ 2025-08-27 7:01 ` Wei Yang
2025-08-27 7:01 ` [Patch v3 2/2] mm/pageblock-flags: remove PB_migratetype_bits/PB_migrate_end Wei Yang
1 sibling, 0 replies; 4+ messages in thread
From: Wei Yang @ 2025-08-27 7:01 UTC (permalink / raw)
To: akpm, david, lorenzo.stoakes, vbabka; +Cc: linux-mm, Wei Yang, Zi Yan
Since commit e904bce2d9d4 ("mm/page_isolation: make page isolation a
standalone bit"), it provides dedicated helper to handle isolation.
Change to use these helpers to be better reading.
No functional change intended.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
mm/page_alloc.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index baead29b3e67..e534f31a6b39 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -538,8 +538,7 @@ static void set_pageblock_migratetype(struct page *page,
"Use set_pageblock_isolate() for pageblock isolation");
return;
}
- VM_WARN_ONCE(get_pfnblock_bit(page, page_to_pfn(page),
- PB_migrate_isolate),
+ VM_WARN_ONCE(get_pageblock_isolate(page),
"Use clear_pageblock_isolate() to unisolate pageblock");
/* MIGRATETYPE_AND_ISO_MASK clears PB_migrate_isolate if it is set */
#endif
@@ -2058,9 +2057,9 @@ static unsigned long find_large_buddy(unsigned long start_pfn)
static inline void toggle_pageblock_isolate(struct page *page, bool isolate)
{
if (isolate)
- set_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate);
+ set_pageblock_isolate(page);
else
- clear_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate);
+ clear_pageblock_isolate(page);
}
/**
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [Patch v3 2/2] mm/pageblock-flags: remove PB_migratetype_bits/PB_migrate_end
2025-08-27 7:01 [Patch v3 0/2] mm/pageblock: improve readability of some pageblock handling Wei Yang
2025-08-27 7:01 ` [Patch v3 1/2] mm/page_alloc: use xxx_pageblock_isolate() for better reading Wei Yang
@ 2025-08-27 7:01 ` Wei Yang
2025-08-27 11:30 ` David Hildenbrand
1 sibling, 1 reply; 4+ messages in thread
From: Wei Yang @ 2025-08-27 7:01 UTC (permalink / raw)
To: akpm, david, lorenzo.stoakes, vbabka; +Cc: linux-mm, Wei Yang, Zi Yan
enum pageblock_bits defines the meaning of pageblock bits. Currently
PB_migratetype_bits says the lowest 3 bits represents migratetype and
PB_migrate_end/MIGRATETYPE_MASK's definition rely on it with magical
computation.
Remove the definition of PB_migratetype_bits/PB_migrate_end. Use
PB_migrate_[0|1|2] to represent lowest bits for migratetype. Then we can
simplify related definition.
Also, MIGRATETYPE_AND_ISO_MASK is MIGRATETYPE_MASK add isolation bit.
Use MIGRATETYPE_MASK in the definition of MIGRATETYPE_AND_ISO_MASK looks
cleaner.
No functional change intended.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
---
v3: fix MIGRATETYPE_MASK defition, thanks ziy
v2: remove PB_migratetype_bits and PB_migrate_end
---
include/linux/pageblock-flags.h | 12 +++++-------
mm/page_alloc.c | 4 ++--
2 files changed, 7 insertions(+), 9 deletions(-)
diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index 6a44be0f39f4..e046278a01fa 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -13,12 +13,11 @@
#include <linux/types.h>
-#define PB_migratetype_bits 3
/* Bit indices that affect a whole block of pages */
enum pageblock_bits {
- PB_migrate,
- PB_migrate_end = PB_migrate + PB_migratetype_bits - 1,
- /* 3 bits required for migrate types */
+ PB_migrate_0,
+ PB_migrate_1,
+ PB_migrate_2,
PB_compact_skip,/* If set the block is skipped by compaction */
#ifdef CONFIG_MEMORY_ISOLATION
@@ -37,11 +36,10 @@ enum pageblock_bits {
#define NR_PAGEBLOCK_BITS (roundup_pow_of_two(__NR_PAGEBLOCK_BITS))
-#define MIGRATETYPE_MASK ((1UL << (PB_migrate_end + 1)) - 1)
+#define MIGRATETYPE_MASK (BIT(PB_migrate_0)|BIT(PB_migrate_1)|BIT(PB_migrate_2))
#ifdef CONFIG_MEMORY_ISOLATION
-#define MIGRATETYPE_AND_ISO_MASK \
- (((1UL << (PB_migrate_end + 1)) - 1) | BIT(PB_migrate_isolate))
+#define MIGRATETYPE_AND_ISO_MASK (MIGRATETYPE_MASK | BIT(PB_migrate_isolate))
#else
#define MIGRATETYPE_AND_ISO_MASK MIGRATETYPE_MASK
#endif
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e534f31a6b39..c1a18aaf8b41 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -355,7 +355,7 @@ static inline int pfn_to_bitidx(const struct page *page, unsigned long pfn)
static __always_inline bool is_standalone_pb_bit(enum pageblock_bits pb_bit)
{
- return pb_bit > PB_migrate_end && pb_bit < __NR_PAGEBLOCK_BITS;
+ return pb_bit >= PB_compact_skip && pb_bit < __NR_PAGEBLOCK_BITS;
}
static __always_inline void
@@ -370,7 +370,7 @@ get_pfnblock_bitmap_bitidx(const struct page *page, unsigned long pfn,
#else
BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
#endif
- BUILD_BUG_ON(__MIGRATE_TYPE_END >= (1 << PB_migratetype_bits));
+ BUILD_BUG_ON(__MIGRATE_TYPE_END > MIGRATETYPE_MASK);
VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
bitmap = get_pageblock_bitmap(page, pfn);
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread