From: David Sterba <dsterba@suse.cz>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Cc: Lu Fengqi <lufq.fnst@cn.fujitsu.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: fix check_shared for fiemap ioctl
Date: Mon, 30 May 2016 17:15:28 +0200 [thread overview]
Message-ID: <20160530151528.GB29147@twin.jikos.cz> (raw)
In-Reply-To: <d228d748-2947-a934-8bc1-afd53127e796@cn.fujitsu.com>
On Fri, May 27, 2016 at 09:39:53AM +0800, Qu Wenruo wrote:
> Any comment?
>
> This patch does not fix the submitted generic/352[1] and generic/353[2]
> test cases, but also introduce a much better structure and design for
> later backref walk use.
>
> Instead of a list and do a O(n^3)~O(n^4) iteration for fiemap ioctl on a
> reflinked(deduped) file, it's now only O(n)~O(nlogn) for SHARED flag
> check to pass generic/352.
This is a good improvement, though there's potentially hidden cost in
the allocations and maintaining the temporary structures. Do you have
actual performance numbers?
next prev parent reply other threads:[~2016-05-30 15:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-16 3:23 [PATCH] btrfs: fix check_shared for fiemap ioctl Lu Fengqi
2016-05-24 3:42 ` luke
2016-05-27 1:39 ` Qu Wenruo
2016-05-30 15:15 ` David Sterba [this message]
2016-05-31 0:38 ` Qu Wenruo
2016-05-30 15:25 ` David Sterba
[not found] ` <f7e6d563-9964-5427-d9ad-cf7db858ad24@cn.fujitsu.com>
[not found] ` <20160531161555.GI29147@suse.cz>
2016-06-01 1:23 ` luke
2016-06-01 15:09 ` David Sterba
[not found] ` <b3c38efb-ddb6-d2b8-34e6-558b1c44065a@cn.fujitsu.com>
[not found] ` <20160531162325.GJ29147@suse.cz>
2016-06-01 5:43 ` luke
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