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From: Christoph Hellwig <hch@lst.de>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Ming Lei <tom.leiming@gmail.com>,
	linux-block <linux-block@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	"open list:XFS FILESYSTEM" <linux-xfs@vger.kernel.org>,
	Dave Chinner <dchinner@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Jens Axboe <axboe@kernel.dk>, Ming Lei <ming.lei@redhat.com>,
	Christoph Lameter <cl@linux.com>
Subject: Re: block: DMA alignment of IO buffer allocated from slab
Date: Fri, 21 Sep 2018 15:05:04 +0200	[thread overview]
Message-ID: <20180921130504.GA22551@lst.de> (raw)
In-Reply-To: <87h8ij0zot.fsf@vitty.brq.redhat.com>

On Fri, Sep 21, 2018 at 03:04:18PM +0200, Vitaly Kuznetsov wrote:
> Christoph Hellwig <hch@lst.de> writes:
> 
> > On Wed, Sep 19, 2018 at 05:15:43PM +0800, Ming Lei wrote:
> >> 1) does kmalloc-N slab guarantee to return N-byte aligned buffer?  If
> >> yes, is it a stable rule?
> >
> > This is the assumption in a lot of the kernel, so I think if somethings
> > breaks this we are in a lot of pain.
> 
> It seems that SLUB debug breaks this assumption. Kernel built with
> 
> CONFIG_SLUB_DEBUG=y
> CONFIG_SLUB=y
> CONFIG_SLUB_DEBUG_ON=y

Looks like we should fix SLUB debug then..

  reply	other threads:[~2018-09-21 13:05 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-19  9:15 block: DMA alignment of IO buffer allocated from slab Ming Lei
2018-09-19  9:41 ` Vitaly Kuznetsov
2018-09-19  9:41   ` Vitaly Kuznetsov
2018-09-19  9:41   ` Vitaly Kuznetsov
2018-09-19 10:02   ` Ming Lei
2018-09-19 10:02     ` Ming Lei
2018-09-19 11:15     ` Vitaly Kuznetsov
2018-09-19 11:15       ` Vitaly Kuznetsov
2018-09-19 11:15       ` Vitaly Kuznetsov
2018-09-20  1:28       ` Ming Lei
2018-09-20  3:59         ` Yang Shi
2018-09-20  6:32         ` Christoph Hellwig
2018-09-20  6:31 ` Christoph Hellwig
2018-09-21 13:04   ` Vitaly Kuznetsov
2018-09-21 13:04     ` Vitaly Kuznetsov
2018-09-21 13:04     ` Vitaly Kuznetsov
2018-09-21 13:05     ` Christoph Hellwig [this message]
2018-09-21 15:00       ` Jens Axboe
2018-09-24 16:06       ` Christopher Lameter
2018-09-24 17:49         ` Jens Axboe
2018-09-24 18:00           ` Christopher Lameter
2018-09-24 18:09             ` Jens Axboe
2018-09-25  7:49               ` Dave Chinner
2018-09-25 15:44                 ` Jens Axboe
2018-09-25 21:04                 ` Matthew Wilcox
2018-09-23 22:42     ` Ming Lei
2018-09-24  9:46       ` Andrey Ryabinin
2018-09-24 14:19         ` Bart Van Assche
2018-09-24 14:43           ` Andrey Ryabinin
2018-09-24 14:43             ` Andrey Ryabinin
2018-09-24 15:08             ` Bart Van Assche
2018-09-24 15:08               ` Bart Van Assche
2018-09-24 15:52               ` Andrey Ryabinin
2018-09-24 15:58                 ` Bart Van Assche
2018-09-24 15:58                   ` Bart Van Assche
2018-09-24 16:07                   ` Andrey Ryabinin
2018-09-24 16:19                     ` Bart Van Assche
2018-09-24 16:19                       ` Bart Van Assche
2018-09-24 16:47                       ` Christopher Lameter
2018-09-24 18:57                       ` Matthew Wilcox
2018-09-24 19:56                         ` Bart Van Assche
2018-09-24 19:56                           ` Bart Van Assche
2018-09-24 20:41                           ` Matthew Wilcox
2018-09-24 20:54                             ` Bart Van Assche
2018-09-24 20:54                               ` Bart Van Assche
2018-09-24 21:09                               ` Matthew Wilcox
2018-09-25  0:16                         ` Ming Lei
2018-09-25  3:28                           ` Matthew Wilcox
2018-09-25  4:10                             ` Bart Van Assche
2018-09-25  4:44                               ` Matthew Wilcox
2018-09-25  6:55                                 ` Ming Lei
2018-09-24 15:17           ` Christopher Lameter
2018-09-25  0:20             ` Ming Lei
2018-09-20 14:07 ` Bart Van Assche
2018-09-21  1:56 ` Dave Chinner
2018-09-21  1:56   ` Dave Chinner
2018-09-21  7:08   ` Christoph Hellwig
2018-09-21  7:25     ` Ming Lei
2018-09-21 14:59       ` Jens Axboe

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