From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from atlas.infra.CARNet.hr (zcalusic@atlas.infra.CARNet.hr [161.53.160.131]) by kvack.org (8.8.7/8.8.7) with ESMTP id PAA16057 for ; Wed, 29 Apr 1998 15:48:17 -0400 Subject: Re: Out of VM idea References: Reply-To: Zlatko.Calusic@CARNet.hr From: Zlatko Calusic Date: 29 Apr 1998 21:46:58 +0200 In-Reply-To: Rik van Riel's message of "Wed, 29 Apr 1998 07:19:51 +0200 (MET DST)" Message-ID: <8790ootnpp.fsf@atlas.infra.CARNet.hr> Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: George , Linux Kernel List , linux-mm@kvack.org List-ID: Rik van Riel writes: > On Tue, 28 Apr 1998, George wrote: > > On Tue, 28 Apr 1998, Rik van Riel wrote: > > > > >Following some observations from Michael Remski (sent > > >to me by private e-mail), I've come to the conlusion > > >that we really should do something about out-of-VM > > >situations. > > > > At the moment, (2.1.98), I can lock my 64 MB machine up with a 'make > > MAKE='make -j20' zImage'. > > > > At the time of memory death: > > * It has 4 megabytes of free pages. > > * It has 6 megabytes of buffer memory. > > * But it dies because it has 0 swap left. > > > > Those hard limits on memory how much memory to not grab should definitely > > go. > > You can tune the buffermem & pagecache amount of memory > in /proc/sys/vm/{buffermem,pagecache}. Every time before he starts compiling, and then return to old values when he's finished? IMNSHO, kernel should be autotuning. > But why your system has 4 MB of free memory I really > don't know... mm/page_alloc.c (in free_memory_available()): /* * If we have more than about 6% of all memory free, * consider it to be good enough for anything. * It may not be, due to fragmentation, but we * don't want to keep on forever trying to find * free unfragmented memory. */ if (nr_free_pages > num_physpages >> 4) return nr+1; With 64MB of memory, last 4MB are almost never used!!! MM in last kernels is not very good. Except Stephens great improvements of the swapping system, where he did a really good job, I believe we did a step backward with recent changes. Regards, -- Posted by Zlatko Calusic E-mail: --------------------------------------------------------------------- (A)bort, (R)etry, (P)retend this never happened...