linux-ext4 - Re: [PATCH V3] ext4: speed-up releasing blocks on commit

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Message-ID: <20130409163648.GA5980@thunk.org>
Date:	Tue, 9 Apr 2013 12:36:48 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Andrey Sidorov <qrxd43@...orola.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH V3] ext4: speed-up releasing blocks on commit

On Thu, Mar 28, 2013 at 11:26:58PM +0400, Andrey Sidorov wrote:
> Improve mb_free_blocks speed by clearing entire range at once instead of
> iterating over each bit. Freeing block-by-block also makes buddy bitmap
> subtree flip twice making most of the work a no-op. Very few bits in buddy
> bitmap require change, e.g. freeing entire group is a 1 bit flip only.
> As a result, releasing blocks of 60G file now takes 5ms instead of 2.7s.
> This is especially good for non-preemptive kernels as there is no
> rescheduling during release.
> 
> Signed-off-by: Andrey Sidorov <qrxd43@...orola.com>

Thanks, added to the dev branch for testing.

					- Ted
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