From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 09 Aug 2001 12:09:11 -0400 From: Chris Mason Subject: Re: 2.4.8-pre7: still buffer cache problems Message-ID: <382140000.997373351@tiny> In-Reply-To: <32774.213.7.60.90.997365391.squirrel@webmail.hbesoftware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: marc heckmann , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org List-ID: On Thursday, August 09, 2001 09:56:31 AM -0400 marc heckmann wrote: > Hi. > > While 2.4.8-pre7 definitely fixes the "dd if=/dev/zero of=bigfile bs=1000k > count=bignumber" case. The "dd if=/dev/hda of=/dev/null" is still quite > broken for me. while I appreciate that it is a case of "root" doing > something stupid, it shouldn't mess up the system so badly. On 2.2.19 the > system is completely useable. on 2.4.8-pre7 it's thrashing swap like mad > and the buffercache is huge. this is all on a PPC [G3] w/ 192Mb's of RAM > and 200MB's of swap. so no highmem is involved. vmstat outputs: > Hmmm, perhaps its because the buffer cache doesn't have any use-once or drop behind optimizations? What happens when you do this instead (assuming your dd supports large files, otherwise use 1000 instead of 9000) dd if=/dev/zero of=some_file seek=9000 bs=1MB count=1 Then, run your test again: dd if=some_file of=/dev/null -chris -- 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-mm.org/