The quilt patch titled
Subject: mm: free up PG_slab
has been removed from the -mm tree. Its filename was
mm-free-up-pg_slab.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: free up PG_slab
Date: Thu, 21 Mar 2024 14:24:45 +0000
Reclaim the Slab page flag by using a spare bit in PageType. We are
perennially short of page flags for various purposes, and now that the
original SLAB allocator has been retired, SLUB does not use the
mapcount/page_type field. This lets us remove a number of special cases
for ignoring mapcount on Slab pages.
[willy@xxxxxxxxxxxxx: update vmcoreinfo]
Link: https://lkml.kernel.org/r/ZgGV-O8WYQ_83kxp@xxxxxxxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20240321142448.1645400-8-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 21 +++++++++++++++++----
include/trace/events/mmflags.h | 2 +-
kernel/vmcore_info.c | 3 ++-
mm/memory-failure.c | 9 ---------
mm/slab.h | 2 +-
5 files changed, 21 insertions(+), 16 deletions(-)
--- a/include/linux/page-flags.h~mm-free-up-pg_slab
+++ a/include/linux/page-flags.h
@@ -109,7 +109,6 @@ enum pageflags {
PG_active,
PG_workingset,
PG_error,
- PG_slab,
PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
PG_arch_1,
PG_reserved,
@@ -524,7 +523,6 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEA
TESTCLEARFLAG(Active, active, PF_HEAD)
PAGEFLAG(Workingset, workingset, PF_HEAD)
TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
-__PAGEFLAG(Slab, slab, PF_NO_TAIL)
PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
/* Xen */
@@ -931,7 +929,7 @@ PAGEFLAG_FALSE(HasHWPoisoned, has_hwpois
#endif
/*
- * For pages that are never mapped to userspace (and aren't PageSlab),
+ * For pages that are never mapped to userspace,
* page_type may be used. Because it is initialised to -1, we invert the
* sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
* __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
@@ -947,6 +945,7 @@ PAGEFLAG_FALSE(HasHWPoisoned, has_hwpois
#define PG_table 0x00000200
#define PG_guard 0x00000400
#define PG_hugetlb 0x00000800
+#define PG_slab 0x00001000
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
@@ -1041,6 +1040,20 @@ PAGE_TYPE_OPS(Table, table, pgtable)
*/
PAGE_TYPE_OPS(Guard, guard, guard)
+FOLIO_TYPE_OPS(slab, slab)
+
+/**
+ * PageSlab - Determine if the page belongs to the slab allocator
+ * @page: The page to test.
+ *
+ * Context: Any context.
+ * Return: True for slab pages, false for any other kind of page.
+ */
+static inline bool PageSlab(const struct page *page)
+{
+ return folio_test_slab(page_folio(page));
+}
+
#ifdef CONFIG_HUGETLB_PAGE
FOLIO_TYPE_OPS(hugetlb, hugetlb)
#else
@@ -1121,7 +1134,7 @@ static __always_inline void __ClearPageA
(1UL << PG_lru | 1UL << PG_locked | \
1UL << PG_private | 1UL << PG_private_2 | \
1UL << PG_writeback | 1UL << PG_reserved | \
- 1UL << PG_slab | 1UL << PG_active | \
+ 1UL << PG_active | \
1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK)
/*
--- a/include/trace/events/mmflags.h~mm-free-up-pg_slab
+++ a/include/trace/events/mmflags.h
@@ -107,7 +107,6 @@
DEF_PAGEFLAG_NAME(lru), \
DEF_PAGEFLAG_NAME(active), \
DEF_PAGEFLAG_NAME(workingset), \
- DEF_PAGEFLAG_NAME(slab), \
DEF_PAGEFLAG_NAME(owner_priv_1), \
DEF_PAGEFLAG_NAME(arch_1), \
DEF_PAGEFLAG_NAME(reserved), \
@@ -135,6 +134,7 @@ IF_HAVE_PG_ARCH_X(arch_3)
#define DEF_PAGETYPE_NAME(_name) { PG_##_name, __stringify(_name) }
#define __def_pagetype_names \
+ DEF_PAGETYPE_NAME(slab), \
DEF_PAGETYPE_NAME(hugetlb), \
DEF_PAGETYPE_NAME(offline), \
DEF_PAGETYPE_NAME(guard), \
--- a/kernel/vmcore_info.c~mm-free-up-pg_slab
+++ a/kernel/vmcore_info.c
@@ -198,7 +198,8 @@ static int __init crash_save_vmcoreinfo_
VMCOREINFO_NUMBER(PG_private);
VMCOREINFO_NUMBER(PG_swapcache);
VMCOREINFO_NUMBER(PG_swapbacked);
- VMCOREINFO_NUMBER(PG_slab);
+#define PAGE_SLAB_MAPCOUNT_VALUE (~PG_slab)
+ VMCOREINFO_NUMBER(PAGE_SLAB_MAPCOUNT_VALUE);
#ifdef CONFIG_MEMORY_FAILURE
VMCOREINFO_NUMBER(PG_hwpoison);
#endif
--- a/mm/memory-failure.c~mm-free-up-pg_slab
+++ a/mm/memory-failure.c
@@ -1251,7 +1251,6 @@ static int me_huge_page(struct page_stat
#define mlock (1UL << PG_mlocked)
#define lru (1UL << PG_lru)
#define head (1UL << PG_head)
-#define slab (1UL << PG_slab)
#define reserved (1UL << PG_reserved)
static struct page_state error_states[] = {
@@ -1261,13 +1260,6 @@ static struct page_state error_states[]
* PG_buddy pages only make a small fraction of all free pages.
*/
- /*
- * Could in theory check if slab page is free or if we can drop
- * currently unused objects without touching them. But just
- * treat it as standard kernel for now.
- */
- { slab, slab, MF_MSG_SLAB, me_kernel },
-
{ head, head, MF_MSG_HUGE, me_huge_page },
{ sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty },
@@ -1294,7 +1286,6 @@ static struct page_state error_states[]
#undef mlock
#undef lru
#undef head
-#undef slab
#undef reserved
static void update_per_node_mf_stats(unsigned long pfn,
--- a/mm/slab.h~mm-free-up-pg_slab
+++ a/mm/slab.h
@@ -84,8 +84,8 @@ struct slab {
};
struct rcu_head rcu_head;
};
- unsigned int __unused;
+ unsigned int __page_type;
atomic_t __page_refcount;
#ifdef CONFIG_SLAB_OBJ_EXT
unsigned long obj_exts;
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
doc-improve-the-description-of-__folio_mark_dirty.patch
buffer-add-kernel-doc-for-block_dirty_folio.patch
buffer-add-kernel-doc-for-try_to_free_buffers.patch
buffer-fix-__bread-and-__bread_gfp-kernel-doc.patch
buffer-add-kernel-doc-for-brelse-and-__brelse.patch
buffer-add-kernel-doc-for-bforget-and-__bforget.patch
buffer-improve-bdev_getblk-documentation.patch
doc-split-bufferrst-out-of-api-summaryrst.patch
doc-split-bufferrst-out-of-api-summaryrst-fix.patch
mm-memory-failure-remove-fsdax_pgoff-argument-from-__add_to_kill.patch
mm-memory-failure-pass-addr-to-__add_to_kill.patch
mm-return-the-address-from-page_mapped_in_vma.patch
mm-make-page_mapped_in_vma-conditional-on-config_memory_failure.patch
mm-memory-failure-convert-shake_page-to-shake_folio.patch
mm-convert-hugetlb_page_mapping_lock_write-to-folio.patch
mm-memory-failure-convert-memory_failure-to-use-a-folio.patch
mm-memory-failure-convert-hwpoison_user_mappings-to-take-a-folio.patch
mm-memory-failure-add-some-folio-conversions-to-unpoison_memory.patch
mm-memory-failure-use-folio-functions-throughout-collect_procs.patch
mm-memory-failure-pass-the-folio-to-collect_procs_ksm.patch
fscrypt-convert-bh_get_inode_and_lblk_num-to-use-a-folio.patch
f2fs-convert-f2fs_clear_page_cache_dirty_tag-to-use-a-folio.patch
memory-failure-remove-calls-to-page_mapping.patch
migrate-expand-the-use-of-folio-in-__migrate_device_pages.patch
userfault-expand-folio-use-in-mfill_atomic_install_pte.patch
mm-remove-page_mapping.patch
mm-remove-page_cache_alloc.patch
mm-remove-put_devmap_managed_page.patch
mm-convert-put_devmap_managed_page_refs-to-put_devmap_managed_folio_refs.patch
mm-remove-page_ref_sub_return.patch
gup-use-folios-for-gup_devmap.patch
mm-add-kernel-doc-for-folio_mark_accessed.patch
mm-remove-pagereferenced.patch
mm-simplify-thp_vma_allowable_order.patch
