From: Chao Yu <yuchao0@huawei.com>
To: Gao Xiang <hsiangkao@redhat.com>
Cc: Eric Biggers <ebiggers@kernel.org>, <jaegeuk@kernel.org>,
<linux-kernel@vger.kernel.org>,
<linux-f2fs-devel@lists.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH v6] f2fs: compress: support compress level
Date: Fri, 4 Dec 2020 11:11:03 +0800 [thread overview]
Message-ID: <15afffcc-636d-b678-0c01-b2fad98d9311@huawei.com> (raw)
In-Reply-To: <20201204024746.GC1963435@xiangao.remote.csb>
On 2020/12/4 10:47, Gao Xiang wrote:
> On Fri, Dec 04, 2020 at 10:38:08AM +0800, Chao Yu wrote:
>> On 2020/12/4 10:06, Gao Xiang wrote:
>>> On Fri, Dec 04, 2020 at 09:56:27AM +0800, Chao Yu wrote:
>
> ...
>
>>
>>>
>>> Keep lz4hc dirty data under writeback could block writeback, make kswapd
>>> busy, and direct memory reclaim path, I guess that's why rare online
>>> compression chooses it. My own premature suggestion is that it'd better
>>> to show the CR or performance benefits in advance, and prevent unprivileged
>>> users from using high-level lz4hc algorithm (to avoid potential system attack.)
>>> either from mount options or ioctl.
>>
>> Yes, I guess you are worry about destop/server scenario, as for android scenario,
>> all compression related flow can be customized, and I don't think we will use
>> online lz4hc compress; for other scenario, except the numbers, I need to add the
>> risk of using lz4hc algorithm in document.
>
> Yes, I was saying the general scenario. My overall premature thought is that
> before releasing some brand new algorithm, it may be better to evaluate first
> it'd benefit to some scenarios first (either on CR or performance side, or
> why adding this?), or it would might cause lzo-rle likewise situation in the
Yeah, got your point.
> future (and add more dependency to algorithms, you might see BWT-based bzip2
> removal patch
Oops, is that really allowed? I don't this is a good idea...and I don't see there
are deletions from fs/ due to similar reason...
Thanks,
> https://lore.kernel.org/r/20201117223253.65920-1-alex_y_xu@yahoo.ca
> (since I personally don't think BWT is a good algorithm as well)... Just FYI
> ... If i'm wrong, kindly ignore me :)
>
> Thanks,
> Gao Xiang
>
>>
>> Thanks,
>
> .
>
next prev parent reply other threads:[~2020-12-04 3:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 6:17 [PATCH v6] f2fs: compress: support compress level Chao Yu
2020-12-03 19:32 ` [f2fs-dev] " Eric Biggers
2020-12-04 0:31 ` Gao Xiang
2020-12-04 1:56 ` Chao Yu
2020-12-04 2:06 ` Gao Xiang
2020-12-04 2:38 ` Chao Yu
2020-12-04 2:47 ` Gao Xiang
2020-12-04 3:11 ` Chao Yu [this message]
2020-12-04 3:21 ` Gao Xiang
2020-12-04 7:09 ` Chao Yu
2020-12-04 7:43 ` Gao Xiang
2020-12-04 8:50 ` Chao Yu
2020-12-04 9:10 ` Gao Xiang
2020-12-04 1:18 ` Chao Yu
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