Patch "KVM: async_pf: do not warn on page allocation failures" has been added to the 4.4-stable tree

Patch "KVM: async_pf: do not warn on page allocation failures" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    KVM: async_pf: do not warn on page allocation failures

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-async_pf-do-not-warn-on-page-allocation-failures.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d7444794a02ff655eda87e3cc54e86b940e7736f Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Fri, 19 Feb 2016 13:11:46 +0100
Subject: KVM: async_pf: do not warn on page allocation failures

From: Christian Borntraeger <borntraeger@de.ibm.com>

commit d7444794a02ff655eda87e3cc54e86b940e7736f upstream.

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 <borntraeger@de.ibm.com>
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 virt/kvm/async_pf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -173,7 +173,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *
 	 * 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;
 


Patches currently in stable-queue which might be from borntraeger@de.ibm.com are

queue-4.4/kvm-s390-fix-memory-overwrites-when-vx-is-disabled.patch
queue-4.4/cgroup-make-sure-a-parent-css-isn-t-offlined-before-its-children.patch
queue-4.4/cpuset-make-mm-migration-asynchronous.patch
queue-4.4/sd-optimal-i-o-size-is-in-bytes-not-sectors.patch
queue-4.4/kvm-s390-fix-guest-fprs-memory-leak.patch
queue-4.4/kvm-async_pf-do-not-warn-on-page-allocation-failures.patch