From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 9740E6B025F for ; Wed, 27 Jul 2016 23:30:41 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id o124so31602562pfg.1 for ; Wed, 27 Jul 2016 20:30:41 -0700 (PDT) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTP id 10si9898885pab.31.2016.07.27.20.30.40 for ; Wed, 27 Jul 2016 20:30:40 -0700 (PDT) From: "Li, Liang Z" Subject: RE: [PATCH v2 repost 4/7] virtio-balloon: speed up inflate/deflate process Date: Thu, 28 Jul 2016 03:30:09 +0000 Message-ID: References: <1469582616-5729-1-git-send-email-liang.z.li@intel.com> <1469582616-5729-5-git-send-email-liang.z.li@intel.com> <5798DB49.7030803@intel.com> <20160728003644-mutt-send-email-mst@kernel.org> In-Reply-To: <20160728003644-mutt-send-email-mst@kernel.org> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "Michael S. Tsirkin" , "Hansen, Dave" Cc: "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "linux-mm@kvack.org" , "virtio-dev@lists.oasis-open.org" , "kvm@vger.kernel.org" , "qemu-devel@nongnu.org" , "dgilbert@redhat.com" , "quintela@redhat.com" , Andrew Morton , Vlastimil Babka , Mel Gorman , Paolo Bonzini , Cornelia Huck , Amit Shah > Subject: Re: [PATCH v2 repost 4/7] virtio-balloon: speed up inflate/defla= te > process >=20 > On Wed, Jul 27, 2016 at 09:03:21AM -0700, Dave Hansen wrote: > > On 07/26/2016 06:23 PM, Liang Li wrote: > > > + vb->pfn_limit =3D VIRTIO_BALLOON_PFNS_LIMIT; > > > + vb->pfn_limit =3D min(vb->pfn_limit, get_max_pfn()); > > > + vb->bmap_len =3D ALIGN(vb->pfn_limit, BITS_PER_LONG) / > > > + BITS_PER_BYTE + 2 * sizeof(unsigned long); > > > + hdr_len =3D sizeof(struct balloon_bmap_hdr); > > > + vb->bmap_hdr =3D kzalloc(hdr_len + vb->bmap_len, GFP_KERNEL); > > > > This ends up doing a 1MB kmalloc() right? That seems a _bit_ big. > > How big was the pfn buffer before? >=20 >=20 > Yes I would limit this to 1G memory in a go, will result in a 32KByte bit= map. >=20 > -- > MST Limit to 1G is bad for the performance, I sent you the test result several = weeks ago. Paste it bellow: ---------------------------------------------------------------------------= --------------------------------------------- About the size of page bitmap, I have test the performance of filling the b= alloon to 15GB with a 16GB RAM VM. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D 32K Byte (cover 1GB of RAM) Time spends on inflating: 2031ms --------------------------------------------- 64K Byte (cover 2GB of RAM) Time spends on inflating: 1507ms -------------------------------------------- 512K Byte (cover 16GB of RAM) Time spends on inflating: 1237ms =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D If possible, a big bitmap is better for performance. Liang -- 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