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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: cl@linux.com
Cc: glommer@parallels.com, penberg@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [linux-next-20130422] Bug in SLAB?
Date: Fri, 10 May 2013 06:54:04 +0900	[thread overview]
Message-ID: <201305100654.FCI28926.HOtMVOJLFFFSQO@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <0000013e89a4ae3c-f2abd075-e096-42b5-891d-e2e5e2af9ecb-000000@email.amazonses.com>

Christoph Lameter wrote:
> -	for (i = 1; i < PAGE_SHIFT + MAX_ORDER; i++) {
> +	for (i = 1; i =< KMALLOC_SHIFT_HIGH; i++) {

  mm/slab.c: In function 'init_node_lock_keys':
  mm/slab.c:568:17: error: expected expression before '<' token

What I'm worrying is:

  /*
   * The largest kmalloc size supported by the SLAB allocators is
   * 32 megabyte (2^25) or the maximum allocatable page order if that is
   * less than 32 MB.
   *
   * WARNING: Its not easy to increase this value since the allocators have
   * to do various tricks to work around compiler limitations in order to
   * ensure proper constant folding.
   */
  #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
                                  (MAX_ORDER + PAGE_SHIFT - 1) : 25)

  extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];

Can we manage with allocating only 26 elements when MAX_ORDER + PAGE_SHIFT > 26
(e.g. PAGE_SIZE == 256 * 1024) ?

Can kmalloc_index()/kmalloc_size()/kmalloc_slab() etc. work correctly when
MAX_ORDER + PAGE_SHIFT > 26 (e.g. PAGE_SIZE == 256 * 1024) ?

  reply	other threads:[~2013-05-09 21:54 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-24 12:08 [linux-next-20130422] Bug in bootup code or debug code? Tetsuo Handa
2013-04-25 12:20 ` [linux-next-20130422] Bug in SLAB? Tetsuo Handa
2013-04-29  2:40   ` Tetsuo Handa
2013-04-29 10:12     ` Pekka Enberg
2013-04-29 14:44       ` Glauber Costa
2013-04-29 14:59         ` Christoph Lameter
2013-04-29 15:16           ` Glauber Costa
2013-04-29 15:46             ` Christoph Lameter
2013-04-29 15:54               ` Glauber Costa
2013-04-29 15:28           ` Tetsuo Handa
2013-04-29 16:16             ` Tetsuo Handa
2013-05-09 12:25               ` Tetsuo Handa
2013-05-09 14:14                 ` Christoph Lameter
2013-05-09 21:54                   ` Tetsuo Handa [this message]
2013-05-10 12:38                     ` Tetsuo Handa
2013-05-10 15:57                       ` Christoph Lameter
     [not found]                         ` <201305272153.HEH51089.OHFQMOOtFLSFVJ@I-love.SAKURA.ne.jp>
2013-06-17 11:59                           ` Tetsuo Handa
2013-04-29 17:48             ` Christoph Lameter
2013-04-29 21:45               ` Tetsuo Handa
2013-04-30 14:26                 ` Christoph Lameter
2013-04-30 16:01                   ` Tetsuo Handa
2013-04-30 17:27                     ` Christoph Lameter
2013-05-01  8:05                       ` Pekka Enberg
2013-05-02 15:12                         ` Christoph Lameter
2013-05-01 12:14                       ` Tetsuo Handa
2013-05-02 11:51                         ` Tetsuo Handa
2013-05-02 20:53                         ` Christoph Lameter
2013-05-03  8:26                           ` Tetsuo Handa
2013-05-03 15:43                             ` Christoph Lameter
2013-05-06  6:59                               ` Geert Uytterhoeven
2013-05-06  7:27                                 ` Pekka Enberg
2013-05-03 18:04                             ` Christoph Lameter
2013-05-03 18:48                               ` Tetsuo Handa
2013-05-03 19:21                                 ` Christoph Lameter
2013-05-04  0:15                                   ` Tetsuo Handa
2013-05-06 13:46                                     ` Christoph Lameter
2013-05-07 10:38                                       ` Tetsuo Handa
2013-05-07 14:28                                         ` Christoph Lameter
2013-07-01 20:09                                           ` Andrew Morton
2013-07-01 21:45                                             ` Tetsuo Handa
2013-07-01 21:53                                               ` Andrew Morton
2013-07-02 12:49                                                 ` Tetsuo Handa
2013-07-02 19:12                                                   ` Andrew Morton
2013-07-07 15:58                                                     ` Pekka Enberg
2013-05-06  6:32                               ` Pekka Enberg
2013-05-06 13:47                                 ` Christoph Lameter
2013-05-06 20:24                               ` Pekka Enberg
2013-05-07 14:23                                 ` Christoph Lameter
2013-05-07 14:44                                   ` Pekka Enberg
2013-05-07 15:40                                     ` Christoph Lameter
2013-04-30 14:34                 ` Christoph Lameter
2013-05-01  8:03                   ` Pekka Enberg
2013-05-02 15:13                     ` Christoph Lameter
2013-04-30 15:16                 ` Fix off by one error in slab.h Christoph Lameter
2013-04-29  2:56   ` [linux-next-20130422] Bug in SLAB? Zhan Jianyu

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