From: Yufen Yu <yuyufen@huawei.com>
To: Song Liu <song@kernel.org>
Cc: linux-raid <linux-raid@vger.kernel.org>,
NeilBrown <neilb@suse.com>,
Guoqing Jiang <guoqing.jiang@cloud.ionos.com>,
Hou Tao <houtao1@huawei.com>
Subject: Re: [PATCH v5 00/16] md/raid5: set STRIPE_SIZE as a configurable value
Date: Wed, 8 Jul 2020 21:14:49 +0800 [thread overview]
Message-ID: <0dd1ebed-2802-2bef-48f0-87bbdd2ee8e5@huawei.com> (raw)
In-Reply-To: <CAPhsuW7PgJV-bjaa8v=Zrhd0MqPmjew1dF-Qi0FP6i-809YAQg@mail.gmail.com>
On 2020/7/3 7:00, Song Liu wrote:
> On Thu, Jul 2, 2020 at 5:05 AM Yufen Yu <yuyufen@huawei.com> wrote:
>>
>> Hi, all
>>
>> For now, STRIPE_SIZE is equal to the value of PAGE_SIZE. That means, RAID5
>> will issue each bio to disk at least 64KB when PAGE_SIZE is 64KB in arm64.
>> However, filesystem usually issue bio in the unit of 4KB. Then, RAID5 may
>> waste resource of disk bandwidth.
>>
>> To solve the problem, this patchset try to set stripe_size as a configuare
>> value. The default value is 4096. We will add a new sysfs entry and set it
>> by writing a new value, likely:
>>
>> echo 16384 > /sys/block/md1/md/stripe_size
>
> Higher level question: do we need to support page size that is NOT 4kB
> times power
> of 2? Meaning, do we need to support 12kB, 20kB, 24kB, etc. If we only
> supports, 4kB,
> 8kB, 16kB, 32kB, etc. some of the logic can be simpler.
Yeah, I think we just support 4kb, 8kb, 16kb, 32kb... is enough.
But Sorry that I don't know what logic can be simpler in current implementation.
I mean it also need to allocate page, and record page offset.
Thanks,
Yufen
next prev parent reply other threads:[~2020-07-08 13:14 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 12:06 [PATCH v5 00/16] md/raid5: set STRIPE_SIZE as a configurable value Yufen Yu
2020-07-02 12:06 ` [PATCH v5 01/16] md/raid456: covert macro define of STRIPE_* as members of struct r5conf Yufen Yu
2020-07-02 14:51 ` kernel test robot
2020-07-02 15:44 ` kernel test robot
2020-07-02 18:15 ` Song Liu
2020-07-02 18:23 ` Paul Menzel
2020-07-12 22:55 ` antlists
2020-07-06 9:09 ` Guoqing Jiang
2020-07-06 11:34 ` Guoqing Jiang
2020-07-08 2:22 ` Yufen Yu
2020-07-02 12:06 ` [PATCH v5 02/16] md/raid5: add sysfs entry to set and show stripe_size Yufen Yu
2020-07-02 22:14 ` Song Liu
2020-07-02 12:06 ` [PATCH v5 03/16] md/raid5: set default stripe_size as 4096 Yufen Yu
2020-07-02 12:06 ` [PATCH v5 04/16] md/raid5: add a member of r5pages for struct stripe_head Yufen Yu
2020-07-02 22:56 ` Song Liu
2020-07-03 1:22 ` Jason Yan
2020-07-02 12:06 ` [PATCH v5 05/16] md/raid5: allocate and free shared pages of r5pages Yufen Yu
2020-07-02 12:06 ` [PATCH v5 06/16] md/raid5: set correct page offset for bi_io_vec in ops_run_io() Yufen Yu
2020-07-02 12:06 ` [PATCH v5 07/16] md/raid5: set correct page offset for async_copy_data() Yufen Yu
2020-07-02 12:06 ` [PATCH v5 08/16] md/raid5: resize stripes and set correct offset when reshape array Yufen Yu
2020-07-02 12:06 ` [PATCH v5 09/16] md/raid5: add new xor function to support different page offset Yufen Yu
2020-07-02 12:06 ` [PATCH v5 10/16] md/raid5: add offset array in scribble buffer Yufen Yu
2020-07-02 12:06 ` [PATCH v5 11/16] md/raid5: compute xor with correct page offset Yufen Yu
2020-07-02 12:06 ` [PATCH v5 12/16] md/raid5: support config stripe_size by sysfs entry Yufen Yu
2020-07-02 22:38 ` Song Liu
2020-07-04 12:25 ` Yufen Yu
2020-07-02 12:06 ` [PATCH v5 13/16] md/raid6: let syndrome computor support different page offset Yufen Yu
2020-07-02 12:06 ` [PATCH v5 14/16] md/raid6: let async recovery function " Yufen Yu
2020-07-02 12:06 ` [PATCH v5 15/16] md/raid6: compute syndrome with correct " Yufen Yu
2020-07-02 12:06 ` [PATCH v5 16/16] raid6test: adaptation with syndrome function Yufen Yu
2020-07-02 23:00 ` [PATCH v5 00/16] md/raid5: set STRIPE_SIZE as a configurable value Song Liu
2020-07-08 13:14 ` Yufen Yu [this message]
2020-07-08 23:55 ` Song Liu
2020-07-09 13:27 ` Yufen Yu
2020-07-10 16:09 ` Song Liu
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