Commit 2d6e4e82 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
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proc: fixup PDE allocation bloat 

24074a35 ("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: default avatarAlexey 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5df66d30

fs/proc/inode.c

+4 −2
Original line number Diff line number Diff line
@@ -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)

fs/proc/internal.h

+7 −10
Original line number Diff line number Diff line
@@ -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 :		\

#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_SLOT - OFFSETOF_PDE_NAME)

#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);

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