From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chegu Vinod Subject: Re: kvm_intel: Could not allocate 42 bytes percpu data Date: Tue, 02 Jul 2013 09:34:50 -0700 Message-ID: <51D3012A.4030306@hp.com> References: <51C897A7.50302@hp.com> <87ehbisstv.fsf@rustcorp.com.au> <51D22931.1080008@hp.com> <8761wth5ph.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: prarit@redhat.com, LKML , Gleb Natapov , Paolo Bonzini , KVM , "Hull, Jim" To: Rusty Russell Return-path: In-Reply-To: <8761wth5ph.fsf@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 7/1/2013 10:49 PM, Rusty Russell wrote: > Chegu Vinod writes: >> On 6/30/2013 11:22 PM, Rusty Russell wrote: >>> Chegu Vinod writes: >>>> Hello, >>>> >>>> Lots (~700+) of the following messages are showing up in the dmesg of a >>>> 3.10-rc1 based kernel (Host OS is running on a large socket count box >>>> with HT-on). >>>> >>>> [ 82.270682] PERCPU: allocation failed, size=42 align=16, alloc from >>>> reserved chunk failed >>>> [ 82.272633] kvm_intel: Could not allocate 42 bytes percpu data >>> Woah, weird.... >>> >>> Oh. Shit. Um, this is embarrassing. >>> >>> Thanks, >>> Rusty. >> >> Thanks for your response! >> >>> === >>> module: do percpu allocation after uniqueness check. No, really! >>> >>> v3.8-rc1-5-g1fb9341 was supposed to stop parallel kvm loads exhausting >>> percpu memory on large machines: >>> >>> Now we have a new state MODULE_STATE_UNFORMED, we can insert the >>> module into the list (and thus guarantee its uniqueness) before we >>> allocate the per-cpu region. >>> >>> In my defence, it didn't actually say the patch did this. Just that >>> we "can". >>> >>> This patch actually *does* it. >>> >>> Signed-off-by: Rusty Russell >>> Tested-by: Noone it seems. >> Your following "updated" fix seems to be working fine on the larger >> socket count machine with HT-on. > OK, did you definitely revert every other workaround? Yes no other workarounds were there when your change was tested. > > If so, please give me a Tested-by: line... FYI.... The actual verification of your change was done by my esteemed colleague :Jim Hull (cc'd) who had access to this larger socket count box. Tested-by: Jim Hull Thanks Vinod > > Thanks, > Rusty. > . >