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proc: fixup PDE allocation bloat

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24074a35c5c975 ("proc: Make inline name size calculation automatic")
started to put PDE allocations into kmalloc-256 which is unnecessary as
~40 character names are very rare.

Put allocation back into kmalloc-192 cache for 64-bit non-debug builds.

Put BUILD_BUG_ON to know when PDE size has gotten out of control.

[adobriyan@gmail.com: fix BUILD_BUG_ON breakage on powerpc64]
  Link: http://lkml.kernel.org/r/20180703191602.GA25521@avx2
Link: http://lkml.kernel.org/r/20180617215732.GA24688@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2018-08-21 21:54:09 -07:00 committed by Linus Torvalds
parent 5df66d306e
commit 2d6e4e822a
2 changed files with 11 additions and 12 deletions
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6
fs/proc/inode.c
View File

@ -105,8 +105,10 @@ void __init proc_init_kmemcache(void)
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_PDE_SLOT, 0, SLAB_PANIC,
OFFSETOF_PDE_NAME, SIZEOF_PDE_INLINE_NAME, NULL);
"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
offsetof(struct proc_dir_entry, inline_name),
SIZEOF_PDE_INLINE_NAME, NULL);
BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
}
static int proc_show_options(struct seq_file *seq, struct dentry *root)

17
fs/proc/internal.h
View File

@ -65,16 +65,13 @@ struct proc_dir_entry {
char inline_name[];
} __randomize_layout;
#define OFFSETOF_PDE_NAME offsetof(struct proc_dir_entry, inline_name)
#define SIZEOF_PDE_SLOT \
(OFFSETOF_PDE_NAME + 34 <= 64 ? 64 : \
OFFSETOF_PDE_NAME + 34 <= 128 ? 128 : \
OFFSETOF_PDE_NAME + 34 <= 192 ? 192 : \
OFFSETOF_PDE_NAME + 34 <= 256 ? 256 : \
OFFSETOF_PDE_NAME + 34 <= 512 ? 512 : \
0)
#define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE_SLOT - OFFSETOF_PDE_NAME)
#define SIZEOF_PDE ( \
sizeof(struct proc_dir_entry) < 128 ? 128 : \
sizeof(struct proc_dir_entry) < 192 ? 192 : \
sizeof(struct proc_dir_entry) < 256 ? 256 : \
sizeof(struct proc_dir_entry) < 512 ? 512 : \
0)
#define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry))
extern struct kmem_cache *proc_dir_entry_cache;
void pde_free(struct proc_dir_entry *pde);