Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   "Sungjong Seo" <sj1557.seo@samsung.com>
To:     "'Hyeongseok Kim'" <hyeongseok@gmail.com>,
        <namjae.jeon@samsung.com>
Cc:     <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>
In-Reply-To: <20210106043945.36546-1-hyeongseok@gmail.com>
Subject: RE: [PATCH] exfat: improve performance of exfat_free_cluster when
 using dirsync mount option
Date:   Thu, 7 Jan 2021 15:23:36 +0900
Message-ID: <244001d6e4bd$a18072f0$e48158d0$@samsung.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Thread-Index: AQE9l3LMTUKYLRjlfrko2bpokujgCAI4/HcfqzyDawA=
Content-Language: ko
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 101P
DLP-Filter: Pass
References: <CGME20210106044038epcas1p2d3488531b0a63c122f7401d4d56b03a8@epcas1p2.samsung.com>
        <20210106043945.36546-1-hyeongseok@gmail.com>
Precedence: bulk

> There are stressful update of cluster allocation bitmap when using dirsync
> mount option which is doing sync buffer on every cluster bit clearing.
> This could result in performance degradation when deleting big size file.
> Fix to update only when the bitmap buffer index is changed would make less
> disk access, improving performance especially for truncate operation.
> 
> Testing with Samsung 256GB sdcard, mounted with dirsync option (mount -t
> exfat /dev/block/mmcblk0p1 /temp/mount -o dirsync)
> 
> Remove 4GB file, blktrace result.
> [Before] : 39 secs.
> Total (blktrace):
>  Reads Queued:      0,        0KiB	 Writes Queued:      32775,
16387KiB
>  Read Dispatches:   0,        0KiB	 Write Dispatches:   32775,
16387KiB
>  Reads Requeued:    0		         Writes Requeued:        0
>  Reads Completed:   0,        0KiB	 Writes Completed:   32775,
16387KiB
>  Read Merges:       0,        0KiB	 Write Merges:           0,
0KiB
>  IO unplugs:        2        	     Timer unplugs:          0
> 
> [After] : 1 sec.
> Total (blktrace):
>  Reads Queued:      0,        0KiB	 Writes Queued:         13,
6KiB
>  Read Dispatches:   0,        0KiB	 Write Dispatches:      13,
6KiB
>  Reads Requeued:    0		         Writes Requeued:        0
>  Reads Completed:   0,        0KiB	 Writes Completed:      13,
6KiB
>  Read Merges:       0,        0KiB	 Write Merges:           0,
0KiB
>  IO unplugs:        1        	     Timer unplugs:          0
> 
> Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>

Looks good.
Thanks for your work!

Acked-by: Sungjong Seo <sj1557.seo@samsung.com>