From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 1/1] KVM: async_pf: do not warn on page allocation failures Date: Fri, 19 Feb 2016 18:23:30 +0100 Message-ID: <56C74F92.4030802@redhat.com> References: <1455883906-115954-1-git-send-email-borntraeger@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Dominik Dingel , KVM To: Christian Borntraeger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50782 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965370AbcBSRXe (ORCPT ); Fri, 19 Feb 2016 12:23:34 -0500 In-Reply-To: <1455883906-115954-1-git-send-email-borntraeger@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On 19/02/2016 13:11, Christian Borntraeger wrote: > In async_pf we try to allocate with NOWAIT to get an element quickly > or fail. This code also handle failures gracefully. Lets silence > potential page allocation failures under load. > > qemu-system-s39: page allocation failure: order:0,mode:0x2200000 > [...] > Call Trace: > ([<00000000001146b8>] show_trace+0xf8/0x148) > [<000000000011476a>] show_stack+0x62/0xe8 > [<00000000004a36b8>] dump_stack+0x70/0x98 > [<0000000000272c3a>] warn_alloc_failed+0xd2/0x148 > [<000000000027709e>] __alloc_pages_nodemask+0x94e/0xb38 > [<00000000002cd36a>] new_slab+0x382/0x400 > [<00000000002cf7ac>] ___slab_alloc.constprop.30+0x2dc/0x378 > [<00000000002d03d0>] kmem_cache_alloc+0x160/0x1d0 > [<0000000000133db4>] kvm_setup_async_pf+0x6c/0x198 > [<000000000013dee8>] kvm_arch_vcpu_ioctl_run+0xd48/0xd58 > [<000000000012fcaa>] kvm_vcpu_ioctl+0x372/0x690 > [<00000000002f66f6>] do_vfs_ioctl+0x3be/0x510 > [<00000000002f68ec>] SyS_ioctl+0xa4/0xb8 > [<0000000000781c5e>] system_call+0xd6/0x264 > [<000003ffa24fa06a>] 0x3ffa24fa06a > > Signed-off-by: Christian Borntraeger > --- > virt/kvm/async_pf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c > index 3531599..db2dd33 100644 > --- a/virt/kvm/async_pf.c > +++ b/virt/kvm/async_pf.c > @@ -172,7 +172,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva, > * do alloc nowait since if we are going to sleep anyway we > * may as well sleep faulting in page > */ > - work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT); > + work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT | __GFP_NOWARN); > if (!work) > return 0; > > Applied for 4.5-rc, thanks. Paolo