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From: Ming Lei <ming.lei@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Bart Van Assche <bvanassche@acm.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	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>, Christoph Lameter <cl@linux.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: block: DMA alignment of IO buffer allocated from slab
Date: Tue, 25 Sep 2018 14:55:18 +0800	[thread overview]
Message-ID: <20180925065517.GA4868@ming.t460p> (raw)
In-Reply-To: <20180925044421.GA11163@bombadil.infradead.org>

On Mon, Sep 24, 2018 at 09:44:21PM -0700, Matthew Wilcox wrote:
> On Mon, Sep 24, 2018 at 09:10:43PM -0700, Bart Van Assche wrote:
> > On 9/24/18 8:28 PM, Matthew Wilcox wrote:
> > > [ ... ] Because if we have to
> > > round all allocations below 64 bytes up to 64 bytes, [ ... ]
> > Have you noticed that in another e-mail in this thread it has been explained
> > why it is not necessary on x86 to align buffers allocated by kmalloc() on a
> > 64-byte boundary even if these buffers are used for DMA?
> 
> Oh, so drivers which do this only break on !x86.  Yes, that'll work
> out great.

It shouldn't break !x86 because ARCH_KMALLOC_MINALIGN handles that.

Thanks,
Ming

  reply	other threads:[~2018-09-25  6:55 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
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 [this message]
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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