From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 10 May 2000 17:16:05 -0700 (PDT) From: Linus Torvalds Subject: Re: [PATCH] Recent VM fiasco - fixed In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: "James H. Cloos Jr." Cc: linux-mm@kvack.org, linux-kernel@vger.rutgers.edu List-ID: Ok, there's a pre7-9 out there, and the biggest change versus pre7-8 is actually how block fs dirty data is flushed out. Instead of just waking up kflushd and hoping for the best, we actually just write it out (and even wait on it, if absolutely required). Which makes the whole process much more streamlined, and makes the numbers more repeatable. It also fixes the problem with dirty buffer cache data much more efficiently than the kflushd approach, and mmap002 is not a problem any more. At least for me. [ I noticed that mmap002 finishes a whole lot faster if I never actually wait for the writes to complete, but that had some nasty behaviour under low memory circumstances, so it's not what pre7-9 actually does. I _suspect_ that I should start actually waiting for pages only when priority reaches 0 - comments welcomed, see fs/buffer.c and the sync_page_buffers() function ] kswapd is still quite aggressive, and will show higher CPU time than before. This is a tweaking issue - I suspect it is too aggressive right now, but it needs more testing and feedback. Just the dirty buffer handling made quite an enormous difference, so please do test this if you hated earlier pre7 kernels. Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/