Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753926AbbD2QIz (ORCPT ); Wed, 29 Apr 2015 12:08:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55915 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753666AbbD2QIx (ORCPT ); Wed, 29 Apr 2015 12:08:53 -0400 From: Bandan Das To: Paolo Bonzini Cc: Jan Kiszka , kvm@vger.kernel.org, Wincy Van , linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: nVMX: Don't return error on nested bitmap memory allocation failure References: <554083D4.8090906@siemens.com> <5540D735.5030103@siemens.com> <5540DB6E.4070108@redhat.com> Date: Wed, 29 Apr 2015 12:08:46 -0400 In-Reply-To: <5540DB6E.4070108@redhat.com> (Paolo Bonzini's message of "Wed, 29 Apr 2015 15:23:58 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1242 Lines: 29 Paolo Bonzini writes: > On 29/04/2015 15:05, Jan Kiszka wrote: >> > Yeah... I hear you. Ok, let me put it this way - Assume that we can >> > defer this allocation up until the point that the nested subsystem is >> > actually used i.e L1 tries running a guest and we try to allocate this >> > area. If get_free_page() failed in that case, would we still want to >> > kill L1 too ? I guess no. >> >> We could block the hypervisor thread on the allocation, just like it >> would block on faults for swapped out pages or new ones that have to be >> reclaimed from the page cache first. So, block on a failure hoping that eventually it will succeed ? > In that case we should avoid making the allocation GFP_ATOMIC to begin with. > > If a GFP_KERNEL allocation failed, returning -ENOMEM from KVM_RUN (which > practically means killing the guest) would actually be a very real > possibility. Sorry Paolo, I missed your point. Isn't the allocation already GFP_KERNEL ? > Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/