From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e3.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l9UISRIa028244 for ; Tue, 30 Oct 2007 14:28:27 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l9UISRNj132452 for ; Tue, 30 Oct 2007 14:28:27 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l9UISQO1012294 for ; Tue, 30 Oct 2007 14:28:26 -0400 Message-ID: <472777C4.2010307@linux.vnet.ibm.com> Date: Tue, 30 Oct 2007 23:58:20 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com MIME-Version: 1.0 Subject: Re: [RFC] [-mm PATCH] Memory controller fix swap charging context in unuse_pte() References: <20071005041406.21236.88707.sendpatchset@balbir-laptop> <4713A2F2.1010408@linux.vnet.ibm.com> <471F3732.5050407@linux.vnet.ibm.com> <4724F0BC.1020209@linux.vnet.ibm.com> <20071028203219.GA7145@linux.vnet.ibm.com> <47265842.5040506@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: Linux Containers , Linux MM Mailing List List-ID: Hugh Dickins wrote: > On Tue, 30 Oct 2007, Balbir Singh wrote: >> At this momemnt, I suspect one of two things >> >> 1. Our mods to swap_state.c are different > > I believe they're the same (just take swap_state.c back to how it > was without mem_cgroup mods) - or would be, if after finding this > effect I hadn't added a "swap_in_cg" switch to move between the > two behaviours to study it better (though I do need to remember > to swapoff and swapon between the two: sometimes I do forget). > >> 2. Our configuration is different, main-memory to swap-size ratio > > I doubt the swapsize is relevant: just so long as there's some (a > little more than 200M I guess); I've got 1GB-2GB on different boxes. > I agree, just wanted to make sure that there is enough swap > There may well be something about our configs that's significantly > different. I'd failed to mention SMP (4 cpu), and that I happen > to have /proc/sys/vm/swappiness 100; but find it happens on UP > also, and when I go back to default swappiness 60. > OK.. so those are out of the equation > I've reordered your mail for more dramatic effect... >> On a real box - a powerpc machine that I have access to > > I've tried on 3 Intel and 1 PowerPC now: the Intels show the OOMs > and the PowerPC does not. I rather doubt it's an Intel versus > PowerPC issue as such, but interesting that we see the same. > Very surprising, I am surprised that it's architecture dependent. Let me try and grab an Intel box and try. >> 1. I don't see the OOM with the mods removed (I have swap >> space at-least twice of RAM - with mem=512M, I have at-least >> 1G of swap). > > mem=512M with 1G of swap, yes, I'm the same. > >> 2. Running under the container is much much faster than running >> swapout in the root container. The machine is almost unusable >> if swapout is run under the root container > > That's rather interesting, isn't it? Probably irrelevant to the > OOM issue we're investigating, but worthy of investigation in itself. > Yes, it irrelevant, but I find it to be a good use case for using the memory controller :-) I found that kswapd running at prio -5, seemed to hog quite a bit of the CPU. But it needs more independent investigation, like you've suggested. > Maybe I saw the same on the PowerPC: I simply forgot to set up the > cgroup one time, and my sequence of three swapouts (sometimes only > two out of three OOM, on those boxes that do OOM) seemed to take a > very long time (but I wasn't trying to do anything else on it at > the same time, so didn't notice if it was "unusable"). > > I'll probe on. > Me too.. I'll try and acquire a good x86_64 box and test on it. > Hugh > > -- > 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/ . > Don't email: email@kvack.org -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL -- 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/ . Don't email: email@kvack.org