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When a THP is split, any subpage that is zero-filled will be mapped to the shared zeropage, hence saving memory. Add selftest to verify this by allocating zero-filled THP and comparing RssAnon before and after split. Link: https://lkml.kernel.org/r/20240830100438.3623486-4-usamaarif642@gmail.com Signed-off-by: Alexander Zhu <alexlzhu@fb.com> Signed-off-by: Usama Arif <usamaarif642@gmail.com> Acked-by: Rik van Riel <riel@surriel.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <ryncsn@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuang Zhai <zhais@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Shuang Zhai <szhai2@cs.rochester.edu> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
65 lines
2.1 KiB
C
65 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <stdint.h>
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#include <stdbool.h>
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#include <sys/mman.h>
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#include <err.h>
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#include <strings.h> /* ffsl() */
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#include <unistd.h> /* _SC_PAGESIZE */
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#define BIT_ULL(nr) (1ULL << (nr))
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#define PM_SOFT_DIRTY BIT_ULL(55)
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#define PM_MMAP_EXCLUSIVE BIT_ULL(56)
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#define PM_UFFD_WP BIT_ULL(57)
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#define PM_FILE BIT_ULL(61)
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#define PM_SWAP BIT_ULL(62)
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#define PM_PRESENT BIT_ULL(63)
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extern unsigned int __page_size;
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extern unsigned int __page_shift;
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static inline unsigned int psize(void)
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{
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if (!__page_size)
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__page_size = sysconf(_SC_PAGESIZE);
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return __page_size;
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}
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static inline unsigned int pshift(void)
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{
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if (!__page_shift)
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__page_shift = (ffsl(psize()) - 1);
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return __page_shift;
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}
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uint64_t pagemap_get_entry(int fd, char *start);
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bool pagemap_is_softdirty(int fd, char *start);
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bool pagemap_is_swapped(int fd, char *start);
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bool pagemap_is_populated(int fd, char *start);
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unsigned long pagemap_get_pfn(int fd, char *start);
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void clear_softdirty(void);
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bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len);
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uint64_t read_pmd_pagesize(void);
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unsigned long rss_anon(void);
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bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size);
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bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size);
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bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size);
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int64_t allocate_transhuge(void *ptr, int pagemap_fd);
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unsigned long default_huge_page_size(void);
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int detect_hugetlb_page_sizes(size_t sizes[], int max);
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int uffd_register(int uffd, void *addr, uint64_t len,
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bool miss, bool wp, bool minor);
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int uffd_unregister(int uffd, void *addr, uint64_t len);
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int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len,
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bool miss, bool wp, bool minor, uint64_t *ioctls);
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unsigned long get_free_hugepages(void);
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/*
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* On ppc64 this will only work with radix 2M hugepage size
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*/
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#define HPAGE_SHIFT 21
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#define HPAGE_SIZE (1 << HPAGE_SHIFT)
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#define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0)
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#define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1))
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