From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95959C83F17 for ; Wed, 30 Aug 2023 18:53:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243832AbjH3St4 (ORCPT ); Wed, 30 Aug 2023 14:49:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242202AbjH3H0W (ORCPT ); Wed, 30 Aug 2023 03:26:22 -0400 Received: from out-248.mta0.migadu.com (out-248.mta0.migadu.com [IPv6:2001:41d0:1004:224b::f8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 789B7CC9 for ; Wed, 30 Aug 2023 00:26:19 -0700 (PDT) Message-ID: <8e298c9f-1ef3-5c99-d7b5-47fd6703cf83@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1693380377; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UQ1Q28mUI4wAI7dYMunCxPxgjzO360+MZ42FSzQKfTM=; b=ssplN9k4AtK5wKKEk1JHLy0iSy3Eoap8VcOCw6gIM/h86ywKqNdgpyoSvBaNis1cwJtQ9P 3dKUhyFLmlhL3UGh5vVPDfdecvvUxkeX1N5Rrz5YlBRHSQ33jw8qRdZ24ieJcKPz0bqyH1 U2F2pQdVJOWv7SibFk0ksf/8FOGuYsA= Date: Wed, 30 Aug 2023 15:26:11 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 09/12] hugetlb_vmemmap: Optimistically set Optimized flag To: Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Muchun Song , Joao Martins , Oscar Salvador , David Hildenbrand , Miaohe Lin , David Rientjes , Anshuman Khandual , Naoya Horiguchi , Barry Song , Michal Hocko , Matthew Wilcox , Xiongchun Duan , Andrew Morton References: <20230825190436.55045-1-mike.kravetz@oracle.com> <20230825190436.55045-10-mike.kravetz@oracle.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <20230825190436.55045-10-mike.kravetz@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/8/26 03:04, Mike Kravetz wrote: > At the beginning of hugetlb_vmemmap_optimize, optimistically set > the HPageVmemmapOptimized flag in the head page. Clear the flag > if the operation fails. > > No change in behavior. However, this will become important in > subsequent patches where we batch delay TLB flushing. We need to > make sure the content in the old and new vmemmap pages are the same. Sorry, I didn't get the point here. Could you elaborate it? > > Signed-off-by: Mike Kravetz > --- > mm/hugetlb_vmemmap.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c > index e390170c0887..500a118915ff 100644 > --- a/mm/hugetlb_vmemmap.c > +++ b/mm/hugetlb_vmemmap.c > @@ -566,7 +566,9 @@ static void __hugetlb_vmemmap_optimize(const struct hstate *h, > if (!vmemmap_should_optimize(h, head)) > return; > > + /* Optimistically assume success */ > static_branch_inc(&hugetlb_optimize_vmemmap_key); > + SetHPageVmemmapOptimized(head); > > vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h); > vmemmap_reuse = vmemmap_start; > @@ -577,10 +579,10 @@ static void __hugetlb_vmemmap_optimize(const struct hstate *h, > * to the page which @vmemmap_reuse is mapped to, then free the pages > * which the range [@vmemmap_start, @vmemmap_end] is mapped to. > */ > - if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse, bulk_pages)) > + if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse, bulk_pages)) { > static_branch_dec(&hugetlb_optimize_vmemmap_key); > - else > - SetHPageVmemmapOptimized(head); > + ClearHPageVmemmapOptimized(head); > + } > } > > /**