From: Zach Brown <zach.brown@oracle.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Jeff Moyer <jmoyer@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [patch] call truncate_inode_pages in the DIO fallback to buffered I/O path
Date: Wed, 04 Oct 2006 10:51:02 -0700 [thread overview]
Message-ID: <4523F486.1000604@oracle.com> (raw)
In-Reply-To: <20061004102522.d58c00ef.akpm@osdl.org>
> Why is this a problem? It's just like someone did a write(), and we'll
> invalidate the pagecache on the next direct-io operation.
This was noticed as a distro regression as they moved from the kernels
that used to invalidate the entire address space on direct io ops to
more modern ones that only invalidate the region being written.
You can end up with significant memory pressure after this change with a
large enough working set on disk.
> eek. truncate_inode_pages() will throw away dirty data. Very dangerous,
> much chin-scratching needed.
Yeah, I failed to tell Jeff that it should be calling
filemap_fdatawrite() first to get things into writeback. (And
presumably not truncating if that returns an error.)
next prev parent reply other threads:[~2006-10-04 17:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-04 17:04 [patch] call truncate_inode_pages in the DIO fallback to buffered I/O path Jeff Moyer
2006-10-04 17:25 ` Andrew Morton
2006-10-04 17:51 ` Zach Brown [this message]
2006-10-04 17:53 ` Jeff Moyer
2006-10-04 18:16 ` Andrew Morton
2006-10-04 18:40 ` Zach Brown
2006-10-04 19:16 ` Andrew Morton
2006-10-04 20:53 ` Jeff Moyer
2006-10-04 21:22 ` Jeff Moyer
2006-10-04 23:55 ` Andrew Morton
2006-10-05 19:31 ` Jeff Moyer
2006-10-06 20:11 ` Andrew Morton
2006-10-11 16:48 ` jmoyer
2006-10-11 18:37 ` Andrew Morton
2006-10-12 22:01 ` Jeff Moyer
2006-10-12 22:37 ` Andrew Morton
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