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From: Shakeel Butt <shakeelb@google.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Linux MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Michal Hocko <mhocko@suse.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH 2/9] mm: support __GFP_REPEAT in kvmalloc_node for >32kB
Date: Thu, 6 Apr 2017 17:45:23 -0700
Message-ID: <CALvZod5hBHjKfumAFmRoS9Wbg06+KTg33wSD=8Ksdrq=Vm1OgA@mail.gmail.com> (raw)
In-Reply-To: <20170306103032.2540-3-mhocko@kernel.org>

On Mon, Mar 6, 2017 at 2:30 AM, Michal Hocko <mhocko@kernel.org> wrote:
> From: Michal Hocko <mhocko@suse.com>
>
> vhost code uses __GFP_REPEAT when allocating vhost_virtqueue resp.
> vhost_vsock because it would really like to prefer kmalloc to the
> vmalloc fallback - see 23cc5a991c7a ("vhost-net: extend device
> allocation to vmalloc") for more context. Michael Tsirkin has also
> noted:
> "
> __GFP_REPEAT overhead is during allocation time.  Using vmalloc means all
> accesses are slowed down.  Allocation is not on data path, accesses are.
> "
>
> The similar applies to other vhost_kvzalloc users.
>
> Let's teach kvmalloc_node to handle __GFP_REPEAT properly. There are two
> things to be careful about. First we should prevent from the OOM killer
> and so have to involve __GFP_NORETRY by default and secondly override
> __GFP_REPEAT for !costly order requests as the __GFP_REPEAT is ignored
> for !costly orders.
>
> Supporting __GFP_REPEAT like semantic for !costly request is possible
> it would require changes in the page allocator. This is out of scope of
> this patch.
>
> This patch shouldn't introduce any functional change.
>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michal Hocko <mhocko@suse.com>
> ---
>  drivers/vhost/net.c   |  9 +++------
>  drivers/vhost/vhost.c | 15 +++------------
>  drivers/vhost/vsock.c |  9 +++------
>  mm/util.c             | 20 ++++++++++++++++----
>  4 files changed, 25 insertions(+), 28 deletions(-)
>

There is a kzalloc/vzalloc call in
drivers/vhost/scsi.c:vhost_scsi_open() which is not converted to
kvzalloc(). Was that intentional?

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  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-06 10:30 [PATCH 0/6 v5] kvmalloc Michal Hocko
2017-03-06 10:30 ` [PATCH 1/9] mm: introduce kv[mz]alloc helpers Michal Hocko
2017-06-02  7:17   ` Levin, Alexander (Sasha Levin)
2017-06-02  7:28     ` Michal Hocko
2017-06-02  7:40       ` Levin, Alexander (Sasha Levin)
2017-06-02  7:50         ` Michal Hocko
2017-03-06 10:30 ` [PATCH 2/9] mm: support __GFP_REPEAT in kvmalloc_node for >32kB Michal Hocko
2017-04-07  0:45   ` Shakeel Butt [this message]
2017-04-07  7:40     ` Michal Hocko
2017-03-06 10:30 ` [PATCH 3/9] rhashtable: simplify a strange allocation pattern Michal Hocko
2017-03-06 10:30 ` [PATCH 4/9] ila: " Michal Hocko
2017-03-06 10:33 ` [PATCH 5/9] xattr: zero out memory copied to userspace in getxattr Michal Hocko
2017-03-06 10:33   ` [PATCH 6/9] treewide: use kv[mz]alloc* rather than opencoded variants Michal Hocko
2017-03-06 10:33   ` [PATCH 7/9] net: use kvmalloc with __GFP_REPEAT rather than open coded variant Michal Hocko
2017-03-30 23:21     ` Shakeel Butt
2017-03-31  8:46       ` Michal Hocko
2017-03-06 10:33   ` [PATCH 8/9] md: use kvmalloc rather than opencoded variant Michal Hocko
2017-03-06 10:33   ` [PATCH 9/9] bcache: use kvmalloc Michal Hocko
  -- strict thread matches above, loose matches on Subject: below --
2017-01-30  9:49 [PATCH 0/6 v3] kvmalloc Michal Hocko
2017-01-30  9:49 ` [PATCH 2/9] mm: support __GFP_REPEAT in kvmalloc_node for >32kB Michal Hocko

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