From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 26 Apr 2001 18:16:06 +0200 (MET DST) From: Szabolcs Szakacsits Subject: Re: Want to allocate almost all the memory with no swap 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: Rik van Riel Cc: Simon Derr , linux-mm@kvack.org List-ID: On Thu, 19 Apr 2001, Rik van Riel wrote: > On Thu, 19 Apr 2001, Simon Derr wrote: > > Actually this is what happens under 2.4.2 : > > when I launch the program, during about one minute kswapd eats 50% cpu, > > and bdflush takes 2-5% cpu, > > One minute later approx, they both stop eating the cpu and my process gets > > almost 100% of the cpu (a PIII 733). > > > > The same happens if I kill and launch my program a second time. > > > [...] Thanks for telling us. It is good to know that kswapd > exhibits this strange behaviour. It's admiteddly not a high > priority thing to fix, but it IS something to keep in mind. Apparently it's already fixed in ac kernels. Could the reduced number of wakeup_kswapd() calls the reason? Szaka ---------- Forwarded message ---------- Date: Thu, 26 Apr 2001 13:49:56 +0200 (MEST) From: Simon Derr To: Szabolcs Szakacsits Subject: Re: Want to allocate almost all the memory with no swap On Fri, 20 Apr 2001, Szabolcs Szakacsits wrote: > Could you try Alan Cox's latest prekernel? It has VM related changes and > your feedbeck could be valuable. > ftp://ftp.fi.kernel.org/pub/linux/kernel/v2.4/ > > And maybe 2.4.3? But Alan's would be more interesting because there are > more significant modifications. > ftp://ftp.kernel.org/pub/linux/kernel/people/alan/2.4/ Hi, I'm sorry I had no time this week to do theses tests. I can report this : when allocating 240 megs of memory, and using mlockall(MCL_CURRENT|MCL_FUTURE) on a 256Megs RAM machine : Under Linux 2.4.2: kswapd eats half of the CPU. A few times it did so for a minute approximatively, and then my process got all the CPU. But some other times kswapd has been taking the CPU much much longer (I did not see the end, I stopped the test before) Under Linux 2.4.3-ac9 : It works great ! kswapd does not eat the CPU at all (well, almost : I see it taking 0.1% CPU during one second, but 'top' is not a very accurate measure tool) Simon. -- 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/