From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 872B36B05C5 for ; Mon, 31 Jul 2017 02:55:13 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id d24so5723779wmi.0 for ; Sun, 30 Jul 2017 23:55:13 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id h11si21761304wrb.480.2017.07.30.23.55.12 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sun, 30 Jul 2017 23:55:12 -0700 (PDT) Date: Mon, 31 Jul 2017 08:55:09 +0200 From: Michal Hocko Subject: Re: [PATCH] mm: don't zero ballooned pages Message-ID: <20170731065508.GE13036@dhcp22.suse.cz> References: <1501474413-21580-1-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1501474413-21580-1-git-send-email-wei.w.wang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Wei Wang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, virtualization@lists.linux-foundation.org, mst@redhat.com, mawilcox@microsoft.com, dave.hansen@intel.com, akpm@linux-foundation.org, zhenwei.pi@youruncloud.com On Mon 31-07-17 12:13:33, Wei Wang wrote: > Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and > shouldn't be given to the host ksmd to scan. Could you point me where this MADV_DONTNEED is done, please? > Therefore, it is not > necessary to zero ballooned pages, which is very time consuming when > the page amount is large. The ongoing fast balloon tests show that the > time to balloon 7G pages is increased from ~491ms to 2.8 seconds with > __GFP_ZERO added. So, this patch removes the flag. Please make it obvious that this is a revert of bb01b64cfab7 ("mm/balloon_compaction.c: enqueue zero page to balloon device"). > Signed-off-by: Wei Wang > --- > mm/balloon_compaction.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c > index 9075aa5..b06d9fe 100644 > --- a/mm/balloon_compaction.c > +++ b/mm/balloon_compaction.c > @@ -24,7 +24,7 @@ struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info) > { > unsigned long flags; > struct page *page = alloc_page(balloon_mapping_gfp_mask() | > - __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_ZERO); > + __GFP_NOMEMALLOC | __GFP_NORETRY); > if (!page) > return NULL; > > -- > 2.7.4 > -- Michal Hocko SUSE Labs -- 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