2023-09-29 19:35:48

by Yajun Deng

[permalink] [raw]
Subject: [PATCH v5 1/2] mm: allow optional initialization of page count and PG_reserved flag

__init_single_page() unconditionally resets page count which is
unnecessary for reserved pages.

To allow skipping page count initialization and marking a page reserved
in one go add flags parameter to __init_single_page().

No functional changes.

Signed-off-by: Yajun Deng <[email protected]>
---
v5: change the subject and commit.
v4: remove the changes of __init_zone_device_page().
v3: Introduce enum init_page_flags.
v2: Introduce INIT_PAGE_COUNT and INIT_PAGE_RESERVED.
v1: https://lore.kernel.org/all/[email protected]/
---
mm/hugetlb.c | 2 +-
mm/internal.h | 8 +++++++-
mm/mm_init.c | 24 +++++++++++++-----------
3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 32dbb4f82470..9c22297d9c57 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3064,7 +3064,7 @@ static void __init hugetlb_folio_init_tail_vmemmap(struct folio *folio,
for (pfn = head_pfn + start_page_number; pfn < end_pfn; pfn++) {
struct page *page = pfn_to_page(pfn);

- __init_single_page(page, pfn, zone, nid);
+ __init_single_page(page, pfn, zone, nid, INIT_PAGE_COUNT);
prep_compound_tail((struct page *)folio, pfn - head_pfn);
ret = page_ref_freeze(page, 1);
VM_BUG_ON(!ret);
diff --git a/mm/internal.h b/mm/internal.h
index d7916f1e9e98..536bbaa11be1 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1209,8 +1209,14 @@ struct vma_prepare {
struct vm_area_struct *remove2;
};

+enum page_init_flags {
+ INIT_PAGE_COUNT = (1 << 0),
+ INIT_PAGE_RESERVED = (1 << 1),
+};
+
void __meminit __init_single_page(struct page *page, unsigned long pfn,
- unsigned long zone, int nid);
+ unsigned long zone, int nid,
+ enum page_init_flags flags);

/* shrinker related functions */
unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg,
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 06a72c223bce..0549e7c3d588 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -557,11 +557,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
}

void __meminit __init_single_page(struct page *page, unsigned long pfn,
- unsigned long zone, int nid)
+ unsigned long zone, int nid,
+ enum page_init_flags flags)
{
mm_zero_struct_page(page);
set_page_links(page, zone, nid, pfn);
- init_page_count(page);
page_mapcount_reset(page);
page_cpupid_reset_last(page);
page_kasan_tag_reset(page);
@@ -572,6 +572,10 @@ void __meminit __init_single_page(struct page *page, unsigned long pfn,
if (!is_highmem_idx(zone))
set_page_address(page, __va(pfn << PAGE_SHIFT));
#endif
+ if (flags & INIT_PAGE_COUNT)
+ init_page_count(page);
+ if (flags & INIT_PAGE_RESERVED)
+ __SetPageReserved(page);
}

#ifdef CONFIG_NUMA
@@ -714,7 +718,7 @@ static void __meminit init_reserved_page(unsigned long pfn, int nid)
if (zone_spans_pfn(zone, pfn))
break;
}
- __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
+ __init_single_page(pfn_to_page(pfn), pfn, zid, nid, INIT_PAGE_COUNT);
}
#else
static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
@@ -821,8 +825,8 @@ static void __init init_unavailable_range(unsigned long spfn,
pfn = pageblock_end_pfn(pfn) - 1;
continue;
}
- __init_single_page(pfn_to_page(pfn), pfn, zone, node);
- __SetPageReserved(pfn_to_page(pfn));
+ __init_single_page(pfn_to_page(pfn), pfn, zone, node,
+ INIT_PAGE_COUNT | INIT_PAGE_RESERVED);
pgcnt++;
}

@@ -884,7 +888,7 @@ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone
}

page = pfn_to_page(pfn);
- __init_single_page(page, pfn, zone, nid);
+ __init_single_page(page, pfn, zone, nid, INIT_PAGE_COUNT);
if (context == MEMINIT_HOTPLUG)
__SetPageReserved(page);

@@ -967,9 +971,6 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
unsigned long zone_idx, int nid,
struct dev_pagemap *pgmap)
{
-
- __init_single_page(page, pfn, zone_idx, nid);
-
/*
* Mark page reserved as it will need to wait for onlining
* phase for it to be fully associated with a zone.
@@ -977,7 +978,8 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
* We can use the non-atomic __set_bit operation for setting
* the flag as we are still initializing the pages.
*/
- __SetPageReserved(page);
+ __init_single_page(page, pfn, zone_idx, nid,
+ INIT_PAGE_COUNT | INIT_PAGE_RESERVED);

/*
* ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
@@ -2058,7 +2060,7 @@ static unsigned long __init deferred_init_pages(struct zone *zone,
} else {
page++;
}
- __init_single_page(page, pfn, zid, nid);
+ __init_single_page(page, pfn, zid, nid, INIT_PAGE_COUNT);
nr_pages++;
}
return (nr_pages);
--
2.25.1