[PATCH/RFC] mm: add and use batched version of __tlb_remove_table()
From: Nikita Yushchenko
Date: Fri Dec 17 2021 - 03:21:17 EST
When batched page table freeing via struct mmu_table_batch is used, the
final freeing in __tlb_remove_table_free() executes a loop, calling
arch hook __tlb_remove_table() to free each table individually.
Shift that loop down to archs. This allows archs to optimize it, by
freeing multiple tables in a single release_pages() call. This is
faster than individual put_page() calls, especially with memcg
accounting enabled.
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Signed-off-by: Nikita Yushchenko <nikita.yushchenko@xxxxxxxxxxxxx>
---
arch/arm/include/asm/tlb.h | 5 ++++
arch/arm64/include/asm/tlb.h | 5 ++++
arch/powerpc/include/asm/book3s/32/pgalloc.h | 8 +++++++
arch/powerpc/include/asm/book3s/64/pgalloc.h | 1 +
arch/powerpc/include/asm/nohash/pgalloc.h | 8 +++++++
arch/powerpc/mm/book3s64/pgtable.c | 8 +++++++
arch/s390/include/asm/tlb.h | 1 +
arch/s390/mm/pgalloc.c | 8 +++++++
arch/sparc/include/asm/pgalloc_64.h | 8 +++++++
arch/x86/include/asm/tlb.h | 5 ++++
include/asm-generic/tlb.h | 2 +-
include/linux/swap.h | 5 +++-
mm/mmu_gather.c | 6 +----
mm/swap_state.c | 24 +++++++++++++++-----
14 files changed, 81 insertions(+), 13 deletions(-)
diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index b8cbe03ad260..37f8a5193581 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -34,6 +34,11 @@ static inline void __tlb_remove_table(void *_table)
free_page_and_swap_cache((struct page *)_table);
}
+static inline void __tlb_remove_tables(void **tables, int nr)
+{
+ free_pages_and_swap_cache_nolru((struct page **)tables, nr);
+}
+
#include <asm-generic/tlb.h>
static inline void
diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index c995d1f4594f..c70dd428e1f6 100644
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -16,6 +16,11 @@ static inline void __tlb_remove_table(void *_table)
free_page_and_swap_cache((struct page *)_table);
}
+static inline void __tlb_remove_tables(void **tables, int nr)
+{
+ free_pages_and_swap_cache_nolru((struct page **)tables, nr);
+}
+
#define tlb_flush tlb_flush
static void tlb_flush(struct mmu_gather *tlb);
diff --git a/arch/powerpc/include/asm/book3s/32/pgalloc.h b/arch/powerpc/include/asm/book3s/32/pgalloc.h
index dc5c039eb28e..880369de688a 100644
--- a/arch/powerpc/include/asm/book3s/32/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/32/pgalloc.h
@@ -66,6 +66,14 @@ static inline void __tlb_remove_table(void *_table)
pgtable_free(table, shift);
}
+static inline void __tlb_remove_tables(void **tables, int nr)
+{
+ int i;
+
+ for (i = 0; i < nr; i++)
+ __tlb_remove_table(tables[i]);
+}
+
static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
unsigned long address)
{
diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h
index e1af0b394ceb..f3dcd735e4ce 100644
--- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
@@ -20,6 +20,7 @@ extern pmd_t *pmd_fragment_alloc(struct mm_struct *, unsigned long);
extern void pmd_fragment_free(unsigned long *);
extern void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift);
extern void __tlb_remove_table(void *_table);
+extern void __tlb_remove_tables(void **tables, int nr);
void pte_frag_destroy(void *pte_frag);
static inline pgd_t *radix__pgd_alloc(struct mm_struct *mm)
diff --git a/arch/powerpc/include/asm/nohash/pgalloc.h b/arch/powerpc/include/asm/nohash/pgalloc.h
index 29c43665a753..170f5fda3dc1 100644
--- a/arch/powerpc/include/asm/nohash/pgalloc.h
+++ b/arch/powerpc/include/asm/nohash/pgalloc.h
@@ -63,6 +63,14 @@ static inline void __tlb_remove_table(void *_table)
pgtable_free(table, shift);
}
+static inline void __tlb_remove_tables(void **tables, int nr)
+{
+ int i;
+
+ for (i = 0; i < nr; i++)
+ __tlb_remove_table(tables[i]);
+}
+
static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
unsigned long address)
{
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 9e16c7b1a6c5..f95fb42fadfa 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -412,6 +412,14 @@ void __tlb_remove_table(void *_table)
return pgtable_free(table, index);
}
+void __tlb_remove_tables(void **tables, int nr)
+{
+ int i;
+
+ for (i = 0; i < nr; i++)
+ __tlb_remove_table(tables[i]);
+}
+
#ifdef CONFIG_PROC_FS
atomic_long_t direct_pages_count[MMU_PAGE_COUNT];
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index fe6407f0eb1b..144d3db1441e 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -23,6 +23,7 @@
*/
void __tlb_remove_table(void *_table);
+void __tlb_remove_tables(void **tables, int nr);
static inline void tlb_flush(struct mmu_gather *tlb);
static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
struct page *page, int page_size);
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index 781965f7210e..6a685a895fdb 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -315,6 +315,14 @@ void __tlb_remove_table(void *_table)
}
}
+void __tlb_remove_tables(void **tables, int nr)
+{
+ int i;
+
+ for (i = 0; i < nr; i++)
+ __tlb_remove_table(tables[i]);
+}
+
/*
* Base infrastructure required to generate basic asces, region, segment,
* and page tables that do not make use of enhanced features like EDAT1.
diff --git a/arch/sparc/include/asm/pgalloc_64.h b/arch/sparc/include/asm/pgalloc_64.h
index 7b5561d17ab1..eb7c9bf46747 100644
--- a/arch/sparc/include/asm/pgalloc_64.h
+++ b/arch/sparc/include/asm/pgalloc_64.h
@@ -92,6 +92,14 @@ static inline void __tlb_remove_table(void *_table)
is_page = true;
pgtable_free(table, is_page);
}
+
+static inline void __tlb_remove_tables(void **tables, int nr)
+{
+ int i;
+
+ for (i = 0; i < nr; i++)
+ __tlb_remove_table(tables[i]);
+}
#else /* CONFIG_SMP */
static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, bool is_page)
{
diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index 1bfe979bb9bc..253a62be888c 100644
--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h
@@ -37,4 +37,9 @@ static inline void __tlb_remove_table(void *table)
free_page_and_swap_cache(table);
}
+static inline void __tlb_remove_tables(void **tables, int nr)
+{
+ free_pages_and_swap_cache_nolru((struct page **)tables, nr);
+}
+
#endif /* _ASM_X86_TLB_H */
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 2c68a545ffa7..923c65d986dc 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -148,7 +148,7 @@
* Useful if your architecture has non-page page directories.
*
* When used, an architecture is expected to provide __tlb_remove_table()
- * which does the actual freeing of these pages.
+ * and __tlb_remove_tables() which do the actual freeing of these pages.
*
* MMU_GATHER_RCU_TABLE_FREE
*
diff --git a/include/linux/swap.h b/include/linux/swap.h
index d1ea44b31f19..86a1b0a61889 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -460,6 +460,7 @@ extern void clear_shadow_from_swap_cache(int type, unsigned long begin,
extern void free_swap_cache(struct page *);
extern void free_page_and_swap_cache(struct page *);
extern void free_pages_and_swap_cache(struct page **, int);
+extern void free_pages_and_swap_cache_nolru(struct page **, int);
extern struct page *lookup_swap_cache(swp_entry_t entry,
struct vm_area_struct *vma,
unsigned long addr);
@@ -565,7 +566,9 @@ static inline struct address_space *swap_address_space(swp_entry_t entry)
#define free_page_and_swap_cache(page) \
put_page(page)
#define free_pages_and_swap_cache(pages, nr) \
- release_pages((pages), (nr));
+ release_pages((pages), (nr))
+#define free_pages_and_swap_cache_nolru(pages, nr) \
+ release_pages((pages), (nr))
static inline void free_swap_cache(struct page *page)
{
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 1b9837419bf9..2faa0d59aeca 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -95,11 +95,7 @@ bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_
static void __tlb_remove_table_free(struct mmu_table_batch *batch)
{
- int i;
-
- for (i = 0; i < batch->nr; i++)
- __tlb_remove_table(batch->tables[i]);
-
+ __tlb_remove_tables(batch->tables, batch->nr);
free_page((unsigned long)batch);
}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 8d4104242100..76c3d4a756a3 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -307,17 +307,29 @@ void free_page_and_swap_cache(struct page *page)
/*
* Passed an array of pages, drop them all from swapcache and then release
- * them. They are removed from the LRU and freed if this is their last use.
+ * them. They are optionally removed from the LRU and freed if this is their
+ * last use.
*/
-void free_pages_and_swap_cache(struct page **pages, int nr)
+static void __free_pages_and_swap_cache(struct page **pages, int nr,
+ bool do_lru)
{
- struct page **pagep = pages;
int i;
- lru_add_drain();
+ if (do_lru)
+ lru_add_drain();
for (i = 0; i < nr; i++)
- free_swap_cache(pagep[i]);
- release_pages(pagep, nr);
+ free_swap_cache(pages[i]);
+ release_pages(pages, nr);
+}
+
+void free_pages_and_swap_cache(struct page **pages, int nr)
+{
+ __free_pages_and_swap_cache(pages, nr, true);
+}
+
+void free_pages_and_swap_cache_nolru(struct page **pages, int nr)
+{
+ __free_pages_and_swap_cache(pages, nr, false);
}
static inline bool swap_use_vma_readahead(void)
--
2.30.2