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| author |   Alexey Dobriyan <adobriyan@gmail.com> | 2018-04-10 16:31:52 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-11 10:28:34 -0700 |
| commit | b4884f23331ae31e9ecb617956986c3b76ab9a91 (patch) | |
| tree | 2f25f7337f1aedbfed4fa18b1b26ffa208136544 /fs/proc/internal.h | |
| parent | proc: test /proc/self/syscall (diff) | |
| download | linux-dev-b4884f23331ae31e9ecb617956986c3b76ab9a91.tar.xz linux-dev-b4884f23331ae31e9ecb617956986c3b76ab9a91.zip | |
proc: move "struct proc_dir_entry" into kmem cache
"struct proc_dir_entry" is variable sized because of 0-length trailing
array for name, however, because of SLAB padding allocations it is
possible to make "struct proc_dir_entry" fixed sized and allocate same
amount of memory.
It buys fine-grained debugging with poisoning and usercopy protection
which is not possible with kmalloc-* caches.
Currently, on 32-bit 91+ byte allocations go into kmalloc-128 and on
64-bit 147+ byte allocations go to kmalloc-192 anyway.
Additional memory is allocated only for 38/46+ byte long names which are
rare or may not even exist in the wild.
Link: http://lkml.kernel.org/r/20180223205504.GA17139@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc/internal.h')
| -rw-r--r-- | fs/proc/internal.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/proc/internal.h b/fs/proc/internal.h index dc00ef8538cb..0ead00771384 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -52,11 +52,20 @@ struct proc_dir_entry { struct proc_dir_entry *parent; struct rb_root_cached subdir; struct rb_node subdir_node; + char *name; umode_t mode; u8 namelen; - char name[]; +#ifdef CONFIG_64BIT +#define SIZEOF_PDE_INLINE_NAME (192-147) +#else +#define SIZEOF_PDE_INLINE_NAME (128-91) +#endif + char inline_name[SIZEOF_PDE_INLINE_NAME]; } __randomize_layout; +extern struct kmem_cache *proc_dir_entry_cache; +void pde_free(struct proc_dir_entry *pde); + union proc_op { int (*proc_get_link)(struct dentry *, struct path *); int (*proc_show)(struct seq_file *m, |