From 2d6e4e822ad8174b59414903ae6b35660032c20a Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 21 Aug 2018 21:54:09 -0700 Subject: [PATCH] proc: fixup PDE allocation bloat 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 Cc: David Howells Cc: Al Viro Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/inode.c | 6 ++++-- fs/proc/internal.h | 17 +++++++---------- 2 files changed, 11 insertions(+), 12 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 85ffbd27f288..fc5306a31a1d 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -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) diff --git a/fs/proc/internal.h b/fs/proc/internal.h index f5b75d258d22..c9d97818a421 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -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); -- 2.20.1