Re: [PATCH v4 1/2] mm: pass page count and reserved to __init_single_page
From: Yajun Deng
Date: Fri Sep 29 2023 - 05:37:33 EST
On 2023/9/29 16:19, Mike Rapoport wrote:
On Thu, Sep 28, 2023 at 04:33:01PM +0800, Yajun Deng wrote:
Subject: mm: pass page count and reserved to __init_single_page
We add pass flags that tell __init_single_page() how to initialize page
count and PG_Reserved, I think a better subject would be:
mm: allow optional initialization of page count and PG_reserved flag
Okay.
When we init a single page, we need to mark that page reserved when it
is reserved. And some pages need to reset page count, such as compound
pages.
Introduce enum init_page_flags, the caller will init page count and mark
page reserved by passing INIT_PAGE_COUNT and INIT_PAGE_RESERVED.
This does not really describe why the change is needed. How about
__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.
Okay.
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
---
v4: move 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/20230922070923.355656-1-yajun.deng@xxxxxxxxx/
---
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 a82dc37669b0..bb9c334a8392 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3196,7 +3196,7 @@ 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..449891ad7fdb 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1209,8 +1209,14 @@ struct vma_prepare {
struct vm_area_struct *remove2;
};
+enum init_page_flags {
enum page_init_flags please
Okay.
+ 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 init_page_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..9716c8a7ade9 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 init_page_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);
There is __SetPageReserved call a few lines below, it can be folded here.
No, There is a #ifdef in front of it. If so, I need to add
__SetPageReserved to another init_reserved_page().
And there is an return before __init_single_page.
I will change INIT_PAGE_COUNT to 0 in next patch.
}
#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