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authorAlexey Dobriyan <adobriyan@gmail.com>2018-04-10 16:31:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-11 10:28:34 -0700
commitb4884f23331ae31e9ecb617956986c3b76ab9a91 (patch)
tree2f25f7337f1aedbfed4fa18b1b26ffa208136544 /fs/proc/inode.c
parentc4219edf1de2af44fd98903f72f6e1ceb7f3c701 (diff)
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/inode.c')
-rw-r--r--fs/proc/inode.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 89618836887d..2cf3b74391ca 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -104,6 +104,10 @@ void __init proc_init_kmemcache(void)
pde_opener_cache =
kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
SLAB_ACCOUNT|SLAB_PANIC, NULL);
+ proc_dir_entry_cache = kmem_cache_create_usercopy(
+ "proc_dir_entry", sizeof(struct proc_dir_entry), 0, SLAB_PANIC,
+ offsetof(struct proc_dir_entry, inline_name),
+ sizeof_field(struct proc_dir_entry, inline_name), NULL);
}
static int proc_show_options(struct seq_file *seq, struct dentry *root)