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From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Eric Dumazet <eric.dumazet@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Joby Poriyath <joby.poriyath@citrix.com>,
Ben Hutchings <bhutchings@solarflare.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: don't use kvzalloc for DMA memory
Date: Wed, 18 Apr 2018 13:38:43 -0700 [thread overview]
Message-ID: <f821bf46-94e9-c794-bc77-600dc19edb9a@gmail.com> (raw)
In-Reply-To: <20180418204229-mutt-send-email-mst@kernel.org>
On 04/18/2018 10:55 AM, Michael S. Tsirkin wrote:
> Imagine you want to pass some data to card.
> Natural thing is to just put it in a variable and start DMA.
> However DMA API disallows stack access nowdays,
> so it's natural to put this within struct device.
>
> See e.g.
>
> commit a725ee3e44e39dab1ec82cc745899a785d2a555e
> Author: Andy Lutomirski <luto@kernel.org>
> Date: Mon Jul 18 15:34:49 2016 -0700
>
> virtio-net: Remove more stack DMA
>
Andy just moved the problem to another one, since at that time we already
had vmalloc() fallback for at least 2 years.
Note that my original patch had :
p = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
if (!p)
p = vzalloc(alloc_size);
So really, normal (less than PAGE_SIZE) allocations would have almost-zero-chance to end up to vmalloc(one_page)
next prev parent reply other threads:[~2018-04-18 20:38 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-18 14:34 Mikulas Patocka
2018-04-18 16:05 ` Eric Dumazet
2018-04-18 16:44 ` Mikulas Patocka
2018-04-18 16:51 ` Eric Dumazet
2018-04-18 17:47 ` David Miller
2018-04-18 17:55 ` Mikulas Patocka
2018-04-18 18:00 ` Michael S. Tsirkin
2018-04-18 17:49 ` Mikulas Patocka
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 16:25 ` Eric Dumazet
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 18:28 ` [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM Vlastimil Babka
2018-04-19 19:47 ` Andrew Morton
2018-04-19 21:19 ` Mikulas Patocka
2018-04-19 23:22 ` Andrew Morton
2018-04-20 12:16 ` Mikulas Patocka
2018-04-20 11:47 ` Matthew Wilcox
2018-04-20 12:20 ` Mikulas Patocka
2018-04-23 15:25 ` Michael S. Tsirkin
2018-04-20 13:08 ` Michal Hocko
2018-04-20 13:41 ` Matthew Wilcox
2018-04-20 13:49 ` Michal Hocko
2018-04-20 20:56 ` Mikulas Patocka
2018-04-20 20:54 ` Mikulas Patocka
2018-04-20 21:02 ` Matthew Wilcox
2018-04-20 21:21 ` Mikulas Patocka
2018-04-21 14:47 ` Matthew Wilcox
2018-04-22 13:03 ` Michal Hocko
2018-04-23 14:24 ` Mikulas Patocka
2018-04-23 15:10 ` Michal Hocko
2018-04-23 23:20 ` Mikulas Patocka
2018-04-23 14:06 ` Mikulas Patocka
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 2:47 ` David Rientjes
2018-04-24 11:04 ` Mikulas Patocka
2018-04-24 3:46 ` Matthew Wilcox
2018-04-24 12:29 ` Mikulas Patocka
2018-04-24 17:16 ` Matthew Wilcox
2018-04-24 18:41 ` Mikulas Patocka
2018-05-15 1:13 ` Joonsoo Kim
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 17:03 ` Michal Hocko
2018-04-24 17:28 ` Mikulas Patocka
2018-04-24 17:38 ` Michal Hocko
2018-04-25 20:02 ` [PATCH] fault-injection: reorder config entries Mikulas Patocka
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 20:20 ` Randy Dunlap
2018-04-25 20:57 ` [PATCH v5] " Mikulas Patocka
2018-04-25 21:11 ` Randy Dunlap
2018-04-25 21:18 ` David Rientjes
2018-04-25 21:22 ` Mikulas Patocka
2018-04-25 22:17 ` [dm-devel] " James Bottomley
2018-04-25 22:42 ` Mikulas Patocka
2018-04-25 22:49 ` David Rientjes
2018-04-25 22:56 ` Mikulas Patocka
2018-04-26 12:58 ` Michal Hocko
2018-04-26 14:28 ` Mikulas Patocka
2018-04-26 14:45 ` James Bottomley
2018-04-26 15:05 ` Mikulas Patocka
2018-04-26 15:24 ` James Bottomley
2018-04-26 15:44 ` Mikulas Patocka
2018-04-26 15:59 ` Michael S. Tsirkin
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 19:14 ` Michael S. Tsirkin
2018-04-26 19:36 ` Mikulas Patocka
2018-04-26 19:45 ` Michael S. Tsirkin
2018-04-26 20:05 ` Mikulas Patocka
2018-04-26 18:58 ` Mikulas Patocka
2018-04-26 19:05 ` Michael S. Tsirkin
2018-04-26 15:55 ` Mikulas Patocka
2018-04-25 23:00 ` Mikulas Patocka
2018-04-25 23:08 ` James Bottomley
2018-04-26 14:55 ` 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 22:21 ` Michael S. Tsirkin
2018-04-26 22:52 ` Mikulas Patocka
2018-04-27 8:25 ` Michal Hocko
2018-04-27 10:20 ` Mikulas Patocka
2018-04-27 23:20 ` Mikulas Patocka
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
2018-04-24 0:25 ` [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM Mikulas Patocka
2018-04-24 13:31 ` Michal Hocko
2018-04-24 15:30 ` Mikulas Patocka
2018-04-24 16:12 ` Michal Hocko
2018-04-24 16:29 ` Michal Hocko
2018-04-24 16:33 ` Mikulas Patocka
2018-05-02 0:36 ` Andrew Morton
2018-05-02 13:33 ` Mike Snitzer
2018-05-02 13:40 ` [dm-devel] " John Stoffel
2018-05-03 17:32 ` [PATCH] " Mikulas Patocka
2018-04-18 17:45 ` [PATCH] net: don't use kvzalloc for DMA memory David Miller
2018-04-18 17:55 ` Michael S. Tsirkin
2018-04-18 20:38 ` Eric Dumazet [this message]
2018-04-19 4:00 ` Michael S. Tsirkin
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