From: Theodore Ts'o <tytso@mit.edu>
To: Zheng Liu <gnehzuil.liu@gmail.com>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Lukas Czerner <lczerner@redhat.com>,
Yongqiang Yang <xiaoqiangnk@gmail.com>,
Allison Henderson <achender@linux.vnet.ibm.com>,
Zheng Liu <wenqing.lz@taobao.com>
Subject: Re: [RFC][PATCH 2/8 v2] ext4: add operations on extent status tree
Date: Wed, 19 Sep 2012 14:34:52 -0400 [thread overview]
Message-ID: <20120919183452.GB28470@thunk.org> (raw)
In-Reply-To: <1345615545-26133-3-git-send-email-wenqing.lz@taobao.com>
On Wed, Aug 22, 2012 at 02:05:39PM +0800, Zheng Liu wrote:
> + * 3. performance analysis
> + * -- overhead
> + * 1. Apart from operations on a delayed extent tree, we need to
> + * down_write(inode->i_data_sem) in delayed write path to maintain delayed
> + * extent tree, this can have impact on parallel read-write and write-write
I'm working on going through this patch set now, and I'm not sure this
is worth holding back on this patch series, but I am really concerned
about the performance impact of this.... it would definitely show up
on some of the scalability testing that Eric Whitney had been doing,
for example.
Given that operations on the delayed extent tree should be fast,
instead of using a mutex, any reason why we can't just add a new
spinlock (I'm not even sure we need a rw_spinlock here) to the
ext4_inode_info structure and use that to serialize operations on the
delayed extent tree?
- Ted
next prev parent reply other threads:[~2012-09-19 18:35 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 6:05 [RFC][PATCH 0/8 v2] ext4: extent status tree (step 1) Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 1/8 v2] ext4: add two structures supporting extent status tree Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 2/8 v2] ext4: add operations on " Zheng Liu
2012-09-19 18:34 ` Theodore Ts'o [this message]
2012-09-24 4:25 ` Zheng Liu
2012-09-19 18:41 ` Theodore Ts'o
2012-09-24 3:35 ` Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 3/8 v2] ext4: initialize " Zheng Liu
2012-09-19 18:53 ` Theodore Ts'o
2012-09-19 19:05 ` Theodore Ts'o
2012-09-24 4:45 ` Zheng Liu
2012-09-25 12:42 ` Zheng Liu
2012-09-25 20:59 ` Theodore Ts'o
2012-09-26 2:09 ` Zheng Liu
2012-09-26 2:47 ` Theodore Ts'o
2012-09-26 3:24 ` Zheng Liu
2012-09-26 3:37 ` Theodore Ts'o
2012-09-26 3:54 ` Zheng Liu
2012-09-26 3:46 ` Theodore Ts'o
2012-09-26 3:59 ` Zheng Liu
2012-09-28 7:27 ` Zheng Liu
2012-09-28 17:42 ` Theodore Ts'o
[not found] ` <CANWLp02F=qDXY_KbhAziPkBe8qGKV6oN3XtSdc5bWOkbDG684g@mail.gmail.com>
2012-09-29 3:07 ` Theodore Ts'o
2012-09-29 13:26 ` Zheng Liu
2012-09-30 14:00 ` Dmitry Monakhov
2012-09-29 13:24 ` Fwd: " Zheng Liu
2012-09-26 8:00 ` Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 4/8 v2] ext4: let ext4 maintain " Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 5/8 v2] ext4: add some tracepoints in " Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 6/8 v2] ext4: reimplement fiemap on " Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 7/8 v2] ext4: reimplement ext4_find_delay_alloc_range " Zheng Liu
2012-08-22 6:05 ` [RFC][PATCH 8/8 v2] ext4: introduce lseek SEEK_DATA/SEEK_HOLE support Zheng Liu
2012-09-20 14:41 ` [RFC][PATCH 0/8 v2] ext4: extent status tree (step 1) Theodore Ts'o
2012-09-21 1:51 ` Zheng Liu
2012-09-21 3:19 ` Yongqiang Yang
2012-09-22 0:02 ` Theodore Ts'o
2012-09-24 3:16 ` Zheng Liu
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