From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 23AB76B05BB for ; Mon, 31 Jul 2017 00:23:47 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id p20so65315953pfj.2 for ; Sun, 30 Jul 2017 21:23:47 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id k71si3814161pfb.517.2017.07.30.21.23.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 30 Jul 2017 21:23:46 -0700 (PDT) From: Wei Wang Subject: [PATCH] mm: don't zero ballooned pages Date: Mon, 31 Jul 2017 12:13:33 +0800 Message-Id: <1501474413-21580-1-git-send-email-wei.w.wang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, virtualization@lists.linux-foundation.org, mst@redhat.com, mawilcox@microsoft.com, mhocko@suse.com, dave.hansen@intel.com, akpm@linux-foundation.org, wei.w.wang@intel.com Cc: zhenwei.pi@youruncloud.com Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and shouldn't be given to the host ksmd to scan. 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. 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 -- 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