From: ebiederm+eric@npwt.net (Eric W. Biederman)
To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Hans Reiser <reiser@ricochet.net>,
Shawn Leas <sleas@ixion.honeywell.com>,
Reiserfs <reiserfs@devlinux.com>,
Ken Tetrick <ktetrick@ixion.honeywell.com>,
linux-mm@kvack.org
Subject: Re: (reiserfs) Re: More on Re: (reiserfs) Reiserfs and ext2fs (was Re: (reiserfs) Sum Benchmarks (these look typical?))
Date: 01 Jul 1998 08:11:46 -0500 [thread overview]
Message-ID: <m13ecl7m25.fsf@flinx.npwt.net> (raw)
In-Reply-To: "Stephen C. Tweedie"'s message of Wed, 1 Jul 1998 10:12:40 +0100
>>>>> "ST" == Stephen C Tweedie <sct@redhat.com> writes:
ST> Hi,
ST> On 30 Jun 1998 19:17:15 -0500, ebiederm+eric@npwt.net (Eric
ST> W. Biederman) said:
>> When either I trace through the code, or a hardware guy convinces me,
>> that it is safe to both write to a page, and do DMA from a page
>> simultaneously I'll believe it.
ST> Read the source code! We already do this. If one process or thread
ST> msync()s a mapped file, its dirty pages get written to disk,
ST> independently of any other processes on the same or other CPUs which
ST> may still have the pages mapped and may still be writing to them. We
ST> don't unmap pages for write; we just mark them non-dirty around all
ST> ptes.
I just took the time and looked.
And in buffer.c in get_hash_table if we are returning a locked buffer,
we always wait on that buffer until it is unlocked. So to date we I
don't see us tempting fate, with writing to locked buffers.
It may be harmless but I have't seen that yet.
Eric
next prev parent reply other threads:[~1998-07-01 14:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.HPP.3.96.980617035608.29950A-100000@ixion.honeywell.com>
[not found] ` <199806221138.MAA00852@dax.dcs.ed.ac.uk>
[not found] ` <358F4FBE.821B333C@ricochet.net>
[not found] ` <m11zsgrvnf.fsf@flinx.npwt.net>
[not found] ` <199806241154.MAA03544@dax.dcs.ed.ac.uk>
[not found] ` <m11zse6ecw.fsf@flinx.npwt.net>
1998-06-25 11:00 ` Stephen C. Tweedie
1998-06-26 15:56 ` Eric W. Biederman
1998-06-29 10:35 ` Stephen C. Tweedie
1998-06-29 19:59 ` Eric W. Biederman
1998-06-30 16:10 ` Stephen C. Tweedie
1998-07-01 0:17 ` Eric W. Biederman
1998-07-01 9:12 ` Stephen C. Tweedie
1998-07-01 12:45 ` Eric W. Biederman
1998-07-01 13:11 ` Eric W. Biederman [this message]
1998-07-01 20:07 ` Stephen C. Tweedie
1998-07-02 15:17 ` Eric W. Biederman
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