b42549ad69
If requested, return the actual mapping size to the caller in addition to the address. journal_file_move_to_object() often performs two successive mmap_cache_get() calls via journal_file_move_to(); one to get the object header, then another to get the entire object when it's larger than the header's size. If mmap_cache_get() returned the actual mapping's size, it's probable that the second mmap_cache_get() could be skipped when the established mapping already encompassed the desired size.
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
#pragma once
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/***
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This file is part of systemd.
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Copyright 2012 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <stdbool.h>
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#include <sys/stat.h>
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/* One context per object type, plus one of the header, plus one "additional" one */
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#define MMAP_CACHE_MAX_CONTEXTS 9
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typedef struct MMapCache MMapCache;
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typedef struct MMapFileDescriptor MMapFileDescriptor;
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MMapCache* mmap_cache_new(void);
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MMapCache* mmap_cache_ref(MMapCache *m);
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MMapCache* mmap_cache_unref(MMapCache *m);
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int mmap_cache_get(
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MMapCache *m,
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MMapFileDescriptor *f,
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int prot,
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unsigned context,
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bool keep_always,
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uint64_t offset,
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size_t size,
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struct stat *st,
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void **ret,
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size_t *ret_size);
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MMapFileDescriptor * mmap_cache_add_fd(MMapCache *m, int fd);
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void mmap_cache_free_fd(MMapCache *m, MMapFileDescriptor *f);
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unsigned mmap_cache_get_hit(MMapCache *m);
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unsigned mmap_cache_get_missed(MMapCache *m);
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bool mmap_cache_got_sigbus(MMapCache *m, MMapFileDescriptor *f);
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