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From: Michal Hocko <mhocko@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: dm-devel@redhat.com, eric.dumazet@gmail.com, mst@redhat.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, linux-mm@kvack.org,
	edumazet@google.com, Mikulas Patocka <mpatocka@redhat.com>,
	bhutchings@solarflare.com,
	Andrew Morton <akpm@linux-foundation.org>,
	David Miller <davem@davemloft.net>,
	Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM
Date: Fri, 20 Apr 2018 15:49:01 +0200	[thread overview]
Message-ID: <20180420134901.GB17484__17100.6673518152$1524232028$gmane$org@dhcp22.suse.cz> (raw)
In-Reply-To: <20180420134136.GD10788@bombadil.infradead.org>

On Fri 20-04-18 06:41:36, Matthew Wilcox wrote:
> On Fri, Apr 20, 2018 at 03:08:52PM +0200, Michal Hocko wrote:
> > > In order to detect these bugs reliably I submit this patch that changes
> > > kvmalloc to always use vmalloc if CONFIG_DEBUG_VM is turned on.
> > 
> > No way. This is just wrong! First of all, you will explode most likely
> > on many allocations of small sizes. Second, CONFIG_DEBUG_VM tends to be
> > enabled quite often.
> 
> I think it'll still suit Mikulas' debugging needs if we always use
> vmalloc for sizes above PAGE_SIZE?

Even if that was the case then this doesn't sounds like CONFIG_DEBUG_VM
material. We do not want a completely different behavior when the config
is enabled. If we really need some better fallback testing coverage
then the fault injection, as suggested by Vlastimil, sounds much more
reasonable to me

-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2018-04-20 13:49 UTC|newest]

Thread overview: 218+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-18 14:34 [PATCH] net: don't use kvzalloc for DMA memory Mikulas Patocka
2018-04-18 16:05 ` Eric Dumazet
2018-04-18 16:44   ` Mikulas Patocka
2018-04-18 16:44   ` Mikulas Patocka
2018-04-18 16:51     ` Eric Dumazet
2018-04-18 16:51     ` Eric Dumazet
2018-04-18 17:47       ` David Miller
2018-04-18 17:47         ` David Miller
2018-04-18 17:55         ` Mikulas Patocka
2018-04-18 17:55         ` Mikulas Patocka
2018-04-18 18:00         ` Michael S. Tsirkin
2018-04-18 18:00           ` Michael S. Tsirkin
2018-04-18 17:49       ` Mikulas Patocka
2018-04-18 17:49       ` Mikulas Patocka
2018-04-18 16:51     ` Eric Dumazet
2018-04-18 17:46     ` David Miller
2018-04-18 17:53       ` Mikulas Patocka
2018-04-19 16:12         ` [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM Mikulas Patocka
2018-04-19 16:12         ` Mikulas Patocka
2018-04-19 16:25           ` Eric Dumazet
2018-04-19 16:25             ` Eric Dumazet
2018-04-19 16:28             ` Mikulas Patocka
2018-04-19 16:28             ` Mikulas Patocka
2018-04-19 16:43           ` Michael S. Tsirkin
2018-04-19 21:27             ` [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_SG Mikulas Patocka
2018-04-19 21:27             ` Mikulas Patocka
2018-04-19 16:43           ` [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM Michael S. Tsirkin
2018-04-19 18:28           ` Vlastimil Babka
2018-04-19 18:28           ` Vlastimil Babka
2018-04-19 19:47           ` Andrew Morton
2018-04-19 19:47           ` Andrew Morton
2018-04-19 21:19             ` Mikulas Patocka
2018-04-19 21:19               ` Mikulas Patocka
2018-04-19 23:22               ` Andrew Morton
2018-04-19 23:22               ` Andrew Morton
2018-04-20 12:16                 ` Mikulas Patocka
2018-04-20 12:16                 ` Mikulas Patocka
2018-04-20 11:47           ` Matthew Wilcox
2018-04-20 11:47             ` Matthew Wilcox
2018-04-20 12:20             ` Mikulas Patocka
2018-04-23 15:25               ` Michael S. Tsirkin
2018-04-23 15:25               ` Michael S. Tsirkin
2018-04-20 12:20             ` Mikulas Patocka
2018-04-20 13:08           ` Michal Hocko
2018-04-20 13:08             ` Michal Hocko
2018-04-20 13:41             ` Matthew Wilcox
2018-04-20 13:41             ` Matthew Wilcox
2018-04-20 13:49               ` Michal Hocko [this message]
2018-04-20 13:49               ` Michal Hocko
2018-04-20 20:56                 ` Mikulas Patocka
2018-04-20 20:56                 ` Mikulas Patocka
2018-04-20 20:54             ` Mikulas Patocka
2018-04-20 21:02               ` Matthew Wilcox
2018-04-20 21:02               ` Matthew Wilcox
2018-04-20 21:21                 ` Mikulas Patocka
2018-04-21 14:47                   ` Matthew Wilcox
2018-04-22 13:03                     ` Michal Hocko
2018-04-22 13:03                     ` Michal Hocko
2018-04-23 14:24                       ` Mikulas Patocka
2018-04-23 15:10                         ` Michal Hocko
2018-04-23 15:10                         ` Michal Hocko
2018-04-23 23:20                           ` Mikulas Patocka
2018-04-23 23:20                             ` Mikulas Patocka
2018-04-23 14:24                       ` Mikulas Patocka
2018-04-23 14:06                     ` Mikulas Patocka
2018-04-23 14:06                     ` Mikulas Patocka
2018-04-23 15:15                       ` Michal Hocko
2018-04-23 15:15                       ` Michal Hocko
2018-04-24  0:06                         ` [PATCH v3] kvmalloc: always use vmalloc if CONFIG_DEBUG_SG Mikulas Patocka
2018-04-24  0:06                         ` Mikulas Patocka
2018-04-24  2:47                           ` David Rientjes
2018-04-24 11:04                             ` Mikulas Patocka
2018-04-24 11:04                               ` Mikulas Patocka
2018-04-24  3:46                           ` Matthew Wilcox
2018-04-24  3:46                           ` Matthew Wilcox
2018-04-24 12:29                             ` Mikulas Patocka
2018-04-24 12:29                             ` Mikulas Patocka
2018-04-24 17:16                               ` Matthew Wilcox
2018-04-24 18:41                                 ` Mikulas Patocka
2018-04-24 18:41                                 ` Mikulas Patocka
2018-05-15  1:13                                   ` Joonsoo Kim
2018-05-15  1:13                                   ` Joonsoo Kim
2018-04-24 17:16                               ` Matthew Wilcox
2018-04-24 12:51                           ` Michal Hocko
2018-04-24 12:51                             ` Michal Hocko
2018-04-24 15:50                             ` Mikulas Patocka
2018-04-24 16:29                               ` Michal Hocko
2018-04-24 17:00                                 ` Mikulas Patocka
2018-04-24 17:00                                   ` Mikulas Patocka
2018-04-24 17:03                                   ` Michal Hocko
2018-04-24 17:03                                     ` Michal Hocko
2018-04-24 17:28                                     ` Mikulas Patocka
2018-04-24 17:38                                       ` Michal Hocko
2018-04-24 17:38                                       ` Michal Hocko
2018-04-25 20:02                                         ` [PATCH] fault-injection: reorder config entries Mikulas Patocka
2018-04-25 20:02                                           ` Mikulas Patocka
2018-04-26  3:21                                           ` Randy Dunlap
2018-04-26  3:21                                           ` Randy Dunlap
2018-04-25 20:02                                         ` [PATCH v4] fault-injection: introduce kvmalloc fallback options Mikulas Patocka
2018-04-25 20:02                                         ` Mikulas Patocka
2018-04-25 20:20                                           ` Randy Dunlap
2018-04-25 20:20                                             ` Randy Dunlap
2018-04-25 20:57                                             ` [PATCH v5] " Mikulas Patocka
2018-04-25 20:57                                               ` Mikulas Patocka
2018-04-25 21:11                                               ` Randy Dunlap
2018-04-25 21:11                                                 ` Randy Dunlap
2018-04-25 21:18                                               ` David Rientjes
2018-04-25 21:22                                                 ` Mikulas Patocka
2018-04-25 21:22                                                 ` Mikulas Patocka
2018-04-25 22:17                                                   ` [dm-devel] " James Bottomley
2018-04-25 22:17                                                     ` James Bottomley
2018-04-25 22:42                                                     ` Mikulas Patocka
2018-04-25 22:42                                                       ` Mikulas Patocka
2018-04-25 22:49                                                       ` David Rientjes
2018-04-25 22:56                                                         ` Mikulas Patocka
2018-04-25 22:56                                                         ` Mikulas Patocka
2018-04-26 12:58                                                       ` Michal Hocko
2018-04-26 12:58                                                         ` Michal Hocko
2018-04-26 14:28                                                         ` Mikulas Patocka
2018-04-26 14:28                                                           ` Mikulas Patocka
2018-04-26 14:45                                                           ` [dm-devel] " James Bottomley
2018-04-26 14:45                                                             ` James Bottomley
2018-04-26 15:05                                                             ` Mikulas Patocka
2018-04-26 15:05                                                               ` Mikulas Patocka
2018-04-26 15:24                                                               ` James Bottomley
2018-04-26 15:24                                                                 ` James Bottomley
2018-04-26 15:44                                                                 ` Mikulas Patocka
2018-04-26 15:44                                                                   ` Mikulas Patocka
2018-04-26 15:44                                                                   ` Mikulas Patocka
2018-04-26 15:59                                                                   ` Michael S. Tsirkin
2018-04-26 15:59                                                                     ` Michael S. Tsirkin
2018-04-26 16:07                                                                     ` Mikulas Patocka
2018-04-26 16:07                                                                       ` Mikulas Patocka
2018-04-26 18:49                                                                       ` Michael S. Tsirkin
2018-04-26 18:54                                                                         ` Mikulas Patocka
2018-04-26 18:54                                                                           ` Mikulas Patocka
2018-04-26 19:14                                                                           ` Michael S. Tsirkin
2018-04-26 19:14                                                                           ` Michael S. Tsirkin
2018-04-26 19:36                                                                             ` Mikulas Patocka
2018-04-26 19:36                                                                               ` Mikulas Patocka
2018-04-26 19:45                                                                               ` Michael S. Tsirkin
2018-04-26 19:45                                                                                 ` Michael S. Tsirkin
2018-04-26 20:05                                                                                 ` Mikulas Patocka
2018-04-26 20:05                                                                                 ` Mikulas Patocka
2018-04-26 18:49                                                                       ` Michael S. Tsirkin
2018-04-26 16:07                                                                     ` Mikulas Patocka
2018-04-26 18:58                                                                     ` Mikulas Patocka
2018-04-26 18:58                                                                     ` Mikulas Patocka
2018-04-26 19:05                                                                       ` Michael S. Tsirkin
2018-04-26 19:05                                                                       ` Michael S. Tsirkin
2018-04-26 15:59                                                                   ` Michael S. Tsirkin
2018-04-26 15:55                                                                 ` Mikulas Patocka
2018-04-26 15:55                                                                 ` Mikulas Patocka
2018-04-26 15:05                                                             ` Mikulas Patocka
2018-04-26 14:28                                                         ` Mikulas Patocka
2018-04-25 22:42                                                     ` Mikulas Patocka
2018-04-25 23:00                                                     ` Mikulas Patocka
2018-04-25 23:00                                                       ` Mikulas Patocka
2018-04-25 23:00                                                       ` Mikulas Patocka
2018-04-25 23:08                                                       ` James Bottomley
2018-04-25 23:08                                                         ` James Bottomley
2018-04-26 14:55                                                         ` Mikulas Patocka
2018-04-26 14:55                                                         ` Mikulas Patocka
2018-04-26 14:55                                                           ` Mikulas Patocka
2018-04-26 14:55                                                           ` Mikulas Patocka
2018-04-26 15:22                                                           ` Mikulas Patocka
2018-04-26 15:22                                                           ` Mikulas Patocka
2018-04-26 15:22                                                             ` Mikulas Patocka
2018-04-26 18:58                                                         ` John Stoffel
2018-04-26 21:50                                                           ` Mikulas Patocka
2018-04-26 21:50                                                             ` Mikulas Patocka
2018-04-26 22:21                                                             ` Michael S. Tsirkin
2018-04-26 22:52                                                               ` Mikulas Patocka
2018-04-26 22:52                                                                 ` Mikulas Patocka
2018-04-27  8:25                                                                 ` Michal Hocko
2018-04-27  8:25                                                                 ` Michal Hocko
2018-04-27 10:20                                                                   ` Mikulas Patocka
2018-04-27 10:20                                                                   ` Mikulas Patocka
2018-04-27 23:20                                                               ` Mikulas Patocka
2018-04-27 23:20                                                               ` Mikulas Patocka
2018-04-26 22:21                                                             ` Michael S. Tsirkin
2018-04-30 18:27                                                             ` John Stoffel
2018-04-30 21:07                                                               ` Mikulas Patocka
2018-05-02 13:38                                                                 ` John Stoffel
2018-05-03 17:40                                                                   ` Mikulas Patocka
2018-05-03 17:40                                                                   ` Mikulas Patocka
2018-04-30 21:07                                                               ` Mikulas Patocka
2018-04-24 17:28                                     ` [PATCH v3] kvmalloc: always use vmalloc if CONFIG_DEBUG_SG Mikulas Patocka
2018-04-24 16:29                               ` Michal Hocko
2018-04-24 15:50                             ` Mikulas Patocka
2018-04-24  0:25                         ` [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM Mikulas Patocka
2018-04-24 13:31                           ` Michal Hocko
2018-04-24 13:31                           ` Michal Hocko
2018-04-24 15:30                             ` Mikulas Patocka
2018-04-24 15:30                               ` Mikulas Patocka
2018-04-24 16:12                               ` Michal Hocko
2018-04-24 16:12                                 ` Michal Hocko
2018-04-24 16:29                                 ` Michal Hocko
2018-04-24 16:29                                   ` Michal Hocko
2018-04-24 16:33                                 ` Mikulas Patocka
2018-04-24 16:33                                   ` Mikulas Patocka
2018-05-02  0:36                                   ` Andrew Morton
2018-05-02  0:36                                     ` Andrew Morton
2018-05-02 13:33                                     ` Mike Snitzer
2018-05-02 13:40                                       ` [dm-devel] " John Stoffel
2018-05-02 13:33                                     ` Mike Snitzer
2018-05-03 17:32                                     ` [PATCH] " Mikulas Patocka
2018-05-03 17:32                                     ` Mikulas Patocka
2018-04-24  0:25                         ` Mikulas Patocka
2018-04-21 14:47                   ` Matthew Wilcox
2018-04-20 21:21                 ` Mikulas Patocka
2018-04-20 20:54             ` Mikulas Patocka
2018-04-18 17:53       ` [PATCH] net: don't use kvzalloc for DMA memory Mikulas Patocka
2018-04-18 17:46     ` David Miller
2018-04-18 17:45   ` David Miller
2018-04-18 17:55   ` Michael S. Tsirkin
2018-04-18 20:38     ` Eric Dumazet
2018-04-19  4:00       ` Michael S. Tsirkin

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