From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 1/2] jbd2: Avoid pointless scanning of checkpoint lists Date: Thu, 18 Sep 2014 00:47:44 -0400 Message-ID: <20140918044744.GE24887@thunk.org> References: <1410946290-5128-1-git-send-email-jack@suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Yuanhan Liu To: Jan Kara Return-path: Received: from imap.thunk.org ([74.207.234.97]:35061 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbaIREru (ORCPT ); Thu, 18 Sep 2014 00:47:50 -0400 Content-Disposition: inline In-Reply-To: <1410946290-5128-1-git-send-email-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Sep 17, 2014 at 11:31:29AM +0200, Jan Kara wrote: > Yuanhan has reported that when he is running fsync(2) heavy workload > creating new files over ramdisk, significant amount of time is spent in > __jbd2_journal_clean_checkpoint_list() trying to clean old transactions > (but they cannot be cleaned up because flusher hasn't yet checkpointed > those buffers). The workload can be generated by: > fs_mark -d /fs/ram0/1 -D 2 -N 2560 -n 1000000 -L 1 -S 1 -s 4096 > > Reduce the amount of scanning by stopping to scan the transaction list > once we find a transaction that cannot be checkpointed. Note that this > way of cleaning is still enough to keep freeing space in the journal > after fully checkpointed transactions. > > Reported-and-tested-by: Yuanhan Liu > Signed-off-by: Jan Kara Applied, thanks. - Ted