forked from mirrors/linux
69eadd6a05
KASAN_TAG_WIDTH is 8 bits for both (HW_TAGS and SW_TAGS), but for HW_TAGS the KASAN_TAG_WIDTH can be 4 bits bits because due to the design of the MTE the memory words for storing metadata only need 4 bits. Change the preprocessor define KASAN_TAG_WIDTH for check if SW_TAGS is define, so KASAN_TAG_WIDTH should be 8 bits, but if HW_TAGS is define, so KASAN_TAG_WIDTH should be 4 bits to save a few flags bits. Link: https://lkml.kernel.org/r/20250428201409.5482-1-trintaeoitogc@gmail.com Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com> Suggested-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
124 lines
3.8 KiB
C
124 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef PAGE_FLAGS_LAYOUT_H
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#define PAGE_FLAGS_LAYOUT_H
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#include <linux/numa.h>
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#include <generated/bounds.h>
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/*
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* When a memory allocation must conform to specific limitations (such
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* as being suitable for DMA) the caller will pass in hints to the
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* allocator in the gfp_mask, in the zone modifier bits. These bits
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* are used to select a priority ordered list of memory zones which
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* match the requested limits. See gfp_zone() in include/linux/gfp.h
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*/
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#if MAX_NR_ZONES < 2
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#define ZONES_SHIFT 0
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#elif MAX_NR_ZONES <= 2
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#define ZONES_SHIFT 1
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#elif MAX_NR_ZONES <= 4
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#define ZONES_SHIFT 2
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#elif MAX_NR_ZONES <= 8
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#define ZONES_SHIFT 3
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#else
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#error ZONES_SHIFT "Too many zones configured"
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#endif
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#define ZONES_WIDTH ZONES_SHIFT
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#ifdef CONFIG_SPARSEMEM
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#include <asm/sparsemem.h>
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#define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
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#else
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#define SECTIONS_SHIFT 0
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#endif
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#ifndef BUILD_VDSO32_64
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/*
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* page->flags layout:
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*
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* There are five possibilities for how page->flags get laid out. The first
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* pair is for the normal case without sparsemem. The second pair is for
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* sparsemem when there is plenty of space for node and section information.
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* The last is when there is insufficient space in page->flags and a separate
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* lookup is necessary.
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*
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* No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS |
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* " plus space for last_cpupid: | NODE | ZONE | LAST_CPUPID ... | FLAGS |
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* classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS |
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* " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS |
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* classic sparse no space for node: | SECTION | ZONE | ... | FLAGS |
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*/
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#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
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#define SECTIONS_WIDTH SECTIONS_SHIFT
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#else
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#define SECTIONS_WIDTH 0
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#endif
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#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_SHIFT \
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<= BITS_PER_LONG - NR_PAGEFLAGS
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#define NODES_WIDTH NODES_SHIFT
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#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
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#error "Vmemmap: No space for nodes field in page flags"
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#else
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#define NODES_WIDTH 0
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#endif
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/*
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* Note that this #define MUST have a value so that it can be tested with
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* the IS_ENABLED() macro.
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*/
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#if NODES_SHIFT != 0 && NODES_WIDTH == 0
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#define NODE_NOT_IN_PAGE_FLAGS 1
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#endif
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#if defined(CONFIG_KASAN_SW_TAGS)
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#define KASAN_TAG_WIDTH 8
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#elif defined(CONFIG_KASAN_HW_TAGS)
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#define KASAN_TAG_WIDTH 4
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#else
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#define KASAN_TAG_WIDTH 0
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#endif
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#ifdef CONFIG_NUMA_BALANCING
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#define LAST__PID_SHIFT 8
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#define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1)
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#define LAST__CPU_SHIFT NR_CPUS_BITS
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#define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1)
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#define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT)
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#else
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#define LAST_CPUPID_SHIFT 0
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#endif
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#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \
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KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
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#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
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#else
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#define LAST_CPUPID_WIDTH 0
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#endif
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#if LAST_CPUPID_SHIFT != 0 && LAST_CPUPID_WIDTH == 0
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#define LAST_CPUPID_NOT_IN_PAGE_FLAGS
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#endif
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#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \
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KASAN_TAG_WIDTH + LAST_CPUPID_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
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#error "Not enough bits in page flags"
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#endif
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/* see the comment on MAX_NR_TIERS */
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#define LRU_REFS_WIDTH min(__LRU_REFS_WIDTH, BITS_PER_LONG - NR_PAGEFLAGS - \
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ZONES_WIDTH - LRU_GEN_WIDTH - SECTIONS_WIDTH - \
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NODES_WIDTH - KASAN_TAG_WIDTH - LAST_CPUPID_WIDTH)
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#define NR_NON_PAGEFLAG_BITS (SECTIONS_WIDTH + NODES_WIDTH + ZONES_WIDTH + \
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LAST_CPUPID_SHIFT + KASAN_TAG_WIDTH + \
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LRU_GEN_WIDTH + LRU_REFS_WIDTH)
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#define NR_UNUSED_PAGEFLAG_BITS (BITS_PER_LONG - \
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(NR_NON_PAGEFLAG_BITS + NR_PAGEFLAGS))
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#endif
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#endif /* _LINUX_PAGE_FLAGS_LAYOUT */
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