From 04cb7502a5d70a6ca230e8c24835dc7dccd39fa7 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 21 Aug 2024 18:39:12 +0100 Subject: [PATCH] zsmalloc: use all available 24 bits of page_type Now that we have an extra 8 bits, we don't need to limit ourselves to supporting a 64KiB page size. I'm sure both Hexagon users are grateful, but it does reduce complexity a little. We can also remove reset_first_obj_offset() as calling __ClearPageZsmalloc() will now reset all 32 bits of page_type. Link: https://lkml.kernel.org/r/20240821173914.2270383-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: David Hildenbrand Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Kent Overstreet Signed-off-by: Andrew Morton --- drivers/block/zram/Kconfig | 1 - mm/Kconfig | 10 ++-------- mm/zsmalloc.c | 15 ++++----------- 3 files changed, 6 insertions(+), 20 deletions(-) diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig index eacf1cba7bf4..7b29cce60ab2 100644 --- a/drivers/block/zram/Kconfig +++ b/drivers/block/zram/Kconfig @@ -2,7 +2,6 @@ config ZRAM tristate "Compressed RAM block device support" depends on BLOCK && SYSFS && MMU - depends on HAVE_ZSMALLOC depends on CRYPTO_LZO || CRYPTO_ZSTD || CRYPTO_LZ4 || CRYPTO_LZ4HC || CRYPTO_842 select ZSMALLOC help diff --git a/mm/Kconfig b/mm/Kconfig index 3936fe4d26d9..5946dcdcaeda 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -128,7 +128,7 @@ config ZSWAP_COMPRESSOR_DEFAULT choice prompt "Default allocator" depends on ZSWAP - default ZSWAP_ZPOOL_DEFAULT_ZSMALLOC if HAVE_ZSMALLOC + default ZSWAP_ZPOOL_DEFAULT_ZSMALLOC if MMU default ZSWAP_ZPOOL_DEFAULT_ZBUD help Selects the default allocator for the compressed cache for @@ -154,7 +154,6 @@ config ZSWAP_ZPOOL_DEFAULT_Z3FOLD config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC bool "zsmalloc" - depends on HAVE_ZSMALLOC select ZSMALLOC help Use the zsmalloc allocator as the default allocator. @@ -187,15 +186,10 @@ config Z3FOLD page. It is a ZBUD derivative so the simplicity and determinism are still there. -config HAVE_ZSMALLOC - def_bool y - depends on MMU - depends on PAGE_SIZE_LESS_THAN_256KB # we want <= 64 KiB - config ZSMALLOC tristate prompt "N:1 compression allocator (zsmalloc)" if ZSWAP - depends on HAVE_ZSMALLOC + depends on MMU help zsmalloc is a slab-based memory allocator designed to store pages of various compression levels efficiently. It achieves diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 2d3163e4da96..73a3ec5b21ad 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -20,7 +20,7 @@ * page->index: links together all component pages of a zspage * For the huge page, this is always 0, so we use this field * to store handle. - * page->page_type: PG_zsmalloc, lower 16 bit locate the first object + * page->page_type: PGTY_zsmalloc, lower 24 bits locate the first object * offset in a subpage of a zspage * * Usage of struct page flags: @@ -452,13 +452,7 @@ static inline struct page *get_first_page(struct zspage *zspage) return first_page; } -#define FIRST_OBJ_PAGE_TYPE_MASK 0xffff - -static inline void reset_first_obj_offset(struct page *page) -{ - VM_WARN_ON_ONCE(!PageZsmalloc(page)); - page->page_type |= FIRST_OBJ_PAGE_TYPE_MASK; -} +#define FIRST_OBJ_PAGE_TYPE_MASK 0xffffff static inline unsigned int get_first_obj_offset(struct page *page) { @@ -468,8 +462,8 @@ static inline unsigned int get_first_obj_offset(struct page *page) static inline void set_first_obj_offset(struct page *page, unsigned int offset) { - /* With 16 bit available, we can support offsets into 64 KiB pages. */ - BUILD_BUG_ON(PAGE_SIZE > SZ_64K); + /* With 24 bits available, we can support offsets into 16 MiB pages. */ + BUILD_BUG_ON(PAGE_SIZE > SZ_16M); VM_WARN_ON_ONCE(!PageZsmalloc(page)); VM_WARN_ON_ONCE(offset & ~FIRST_OBJ_PAGE_TYPE_MASK); page->page_type &= ~FIRST_OBJ_PAGE_TYPE_MASK; @@ -808,7 +802,6 @@ static void reset_page(struct page *page) ClearPagePrivate(page); set_page_private(page, 0); page->index = 0; - reset_first_obj_offset(page); __ClearPageZsmalloc(page); } -- 2.25.1