From: Jerome Marchand <jmarchan@redhat.com>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>, Jens Axboe <axboe@kernel.dk>,
Hyeoncheol Lee <cheol.lee@lge.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Robert Jennings <rcj@linux.vnet.ibm.com>
Subject: Re: [RFC] blk: increase logical_block_size to unsigned int
Date: Mon, 9 Jan 2017 10:09:20 -0500 (EST) [thread overview]
Message-ID: <978119764.6177321.1483974560473.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <20170109143344.GA753@tigerII.localdomain>
----- Original Message -----
> From: "Sergey Senozhatsky" <sergey.senozhatsky@gmail.com>
> To: "Minchan Kim" <minchan@kernel.org>
> Cc: "Jens Axboe" <axboe@kernel.dk>, "Hyeoncheol Lee" <cheol.lee@lge.com>, linux-block@vger.kernel.org,
> linux-kernel@vger.kernel.org, "Andrew Morton" <akpm@linux-foundation.org>, "Sergey Senozhatsky"
> <sergey.senozhatsky@gmail.com>, "Robert Jennings" <rcj@linux.vnet.ibm.com>, "Jerome Marchand" <jmarchan@redhat.com>
> Sent: Monday, January 9, 2017 3:33:44 PM
> Subject: Re: [RFC] blk: increase logical_block_size to unsigned int
>
> On (01/09/17 14:04), Minchan Kim wrote:
> > Mostly, zram is used as swap system on embedded world so it want to do IO
> > as PAGE_SIZE aligned/size IO unit. For that, one of the problem was
> > blk_queue_logical_block_size(zram->disk->queue, PAGE_SIZE) made overflow
> > in *64K page system* so [1] changed it to constant 4096.
> > Since that, partial IO can happen so zram should handle it which makes zram
> > complicated[2].
> >
>
> I thought that zram partial IO support is there because some file
> systems cannot cope with large logical_block_size. like FAT, for
> example. am I wrong?
Yes indeed. When we discussed the patch adding the partial I/O, increasing the
size of logical_block was considered. The reason we didn't go the easy path was
that not all block users could handle 64k blocks. FAT is one of them.
Jerome
>
> -ss
>
next prev parent reply other threads:[~2017-01-09 15:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-09 5:04 [RFC] blk: increase logical_block_size to unsigned int Minchan Kim
2017-01-09 14:33 ` Sergey Senozhatsky
2017-01-09 15:09 ` Jerome Marchand [this message]
2017-01-10 22:54 ` Minchan Kim
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