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From: Phillip Susi <phill@thesusis.net>
To: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>,
	linux-fsdevel@vger.kernel.org,
	Phillip Lougher <phillip@squashfs.org.uk>,
	linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org,
	linux-ntfs-dev@lists.sourceforge.net, ntfs3@lists.linux.dev,
	linux-bcache@vger.kernel.org, David Howells <dhowells@redhat.com>,
	Hsin-Yi Wang <hsinyi@chromium.org>
Subject: Re: Readahead for compressed data
Date: Mon, 25 Oct 2021 14:59:45 -0400	[thread overview]
Message-ID: <87fssprkql.fsf@vps.thesusis.net> (raw)
In-Reply-To: <20211022084127.GA1026@quack2.suse.cz>


Jan Kara <jack@suse.cz> writes:

> Well, one of the problems with keeping compressed data is that for mmap(2)
> you have to have pages decompressed so that CPU can access them. So keeping
> compressed data in the page cache would add a bunch of complexity. That
> being said keeping compressed data cached somewhere else than in the page
> cache may certainly me worth it and then just filling page cache on demand
> from this data...

True... Did that multi generational LRU cache ever get merged?  I was
thinking you could use that to make sure that the kernel prefers to
reclaim the decompressed pages in favor of keeping the compressed ones
around.


  parent reply	other threads:[~2021-10-25 19:02 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-21 20:17 Readahead for compressed data Matthew Wilcox
2021-10-22  0:22 ` Gao Xiang
2021-10-22  1:04 ` Phillip Susi
2021-10-22  1:28   ` Gao Xiang
2021-10-22  1:39     ` Gao Xiang
2021-10-22  2:09   ` Phillip Lougher
2021-10-22  2:31     ` Gao Xiang
2021-10-22  8:41   ` Jan Kara
2021-10-22  9:11     ` Gao Xiang
2021-10-22  9:22       ` Qu Wenruo
2021-10-22  9:39         ` Gao Xiang
2021-10-22  9:54           ` Gao Xiang
2021-10-22 10:40             ` Qu Wenruo
2021-10-25 18:59     ` Phillip Susi [this message]
2021-10-22  4:36 ` Phillip Lougher
2021-10-29  6:15 ` Coly Li

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