The quilt patch titled
Subject: mm: init page count in reserve_bootmem_region when MEMINIT_EARLY
has been removed from the -mm tree. Its filename was
mm-init-page-count-in-reserve_bootmem_region-when-meminit_early.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Yajun Deng <yajun.deng@xxxxxxxxx>
Subject: mm: init page count in reserve_bootmem_region when MEMINIT_EARLY
Date: Thu, 28 Sep 2023 16:33:02 +0800
memmap_init_range() would init page count of all pages, but the free pages
count would be reset in __free_pages_core(). There are opposite
operations. It's unnecessary and time-consuming when it's MEMINIT_EARLY
context.
Init page count in reserve_bootmem_region when in MEMINIT_EARLY context,
and check the page count before reset it.
At the same time, the INIT_LIST_HEAD in reserve_bootmem_region isn't
need, as it already done in __init_single_page.
The following data was tested on an x86 machine with 190GB of RAM.
before:
free_low_memory_core_early() 341ms
after:
free_low_memory_core_early() 285ms
Link: https://lkml.kernel.org/r/20230928083302.386202-3-yajun.deng@xxxxxxxxx
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mm_init.c | 18 +++++++++++++-----
mm/page_alloc.c | 20 ++++++++++++--------
2 files changed, 25 insertions(+), 13 deletions(-)
--- a/mm/mm_init.c~mm-init-page-count-in-reserve_bootmem_region-when-meminit_early
+++ a/mm/mm_init.c
@@ -718,7 +718,7 @@ static void __meminit init_reserved_page
if (zone_spans_pfn(zone, pfn))
break;
}
- __init_single_page(pfn_to_page(pfn), pfn, zid, nid, INIT_PAGE_COUNT);
+ __init_single_page(pfn_to_page(pfn), pfn, zid, nid, 0);
}
#else
static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
@@ -756,8 +756,8 @@ void __meminit reserve_bootmem_region(ph
init_reserved_page(start_pfn, nid);
- /* Avoid false-positive PageTail() */
- INIT_LIST_HEAD(&page->lru);
+ /* Init page count for reserved region */
+ init_page_count(page);
/*
* no need for atomic set_bit because the struct
@@ -888,9 +888,17 @@ void __meminit memmap_init_range(unsigne
}
page = pfn_to_page(pfn);
- __init_single_page(page, pfn, zone, nid, INIT_PAGE_COUNT);
- if (context == MEMINIT_HOTPLUG)
+
+ /* If the context is MEMINIT_EARLY, we will init page count and
+ * mark page reserved in reserve_bootmem_region, the free region
+ * wouldn't have page count and we will check the pages count
+ * in __free_pages_core.
+ */
+ __init_single_page(page, pfn, zone, nid, 0);
+ if (context == MEMINIT_HOTPLUG) {
+ init_page_count(page);
__SetPageReserved(page);
+ }
/*
* Usually, we want to mark the pageblock MIGRATE_MOVABLE,
--- a/mm/page_alloc.c~mm-init-page-count-in-reserve_bootmem_region-when-meminit_early
+++ a/mm/page_alloc.c
@@ -1289,18 +1289,22 @@ void __free_pages_core(struct page *page
unsigned int loop;
/*
- * When initializing the memmap, __init_single_page() sets the refcount
- * of all pages to 1 ("allocated"/"not free"). We have to set the
- * refcount of all involved pages to 0.
+ * When initializing the memmap, memmap_init_range sets the refcount
+ * of all pages to 1 ("reserved" and "free") in hotplug context. We
+ * have to set the refcount of all involved pages to 0. Otherwise,
+ * we don't do it, as reserve_bootmem_region only set the refcount on
+ * reserve region ("reserved") in early context.
*/
- prefetchw(p);
- for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
- prefetchw(p + 1);
+ if (page_count(page)) {
+ prefetchw(p);
+ for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
+ prefetchw(p + 1);
+ __ClearPageReserved(p);
+ set_page_count(p, 0);
+ }
__ClearPageReserved(p);
set_page_count(p, 0);
}
- __ClearPageReserved(p);
- set_page_count(p, 0);
atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
_
Patches currently in -mm which might be from yajun.deng@xxxxxxxxx are
mm-mm_initc-remove-redundant-pr_info-when-node-is-memoryless.patch
