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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80ABBC433E1 for ; Mon, 22 Mar 2021 14:16:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 546056196C for ; Mon, 22 Mar 2021 14:16:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229930AbhCVOQG (ORCPT ); Mon, 22 Mar 2021 10:16:06 -0400 Received: from mx2.suse.de ([195.135.220.15]:54324 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230085AbhCVOPp (ORCPT ); Mon, 22 Mar 2021 10:15:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1616422544; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=duDDEf2Xm5uPkuZN+qB6EpLuAaJtGoQSQbHz8dth7zA=; b=XNAfDnvmGf3UeHuucC72Nsq8TCB7iDCUBGB8qBvQyljEkitmgXtNfcuqpBMKSfNrfczCHH IfLDHoiOXncEK4w57k7cqUlbVqSQGeU2Oj63ZWZrk2Sadvm1XmL/mVJimUkq98i3QmWTIo NgD+mSAjDEqNFsWobtwHbZusVYd6864= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3B508ACA8; Mon, 22 Mar 2021 14:15:44 +0000 (UTC) Date: Mon, 22 Mar 2021 15:15:43 +0100 From: Michal Hocko To: Mike Kravetz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shakeel Butt , Oscar Salvador , David Hildenbrand , Muchun Song , David Rientjes , Miaohe Lin , Peter Zijlstra , Matthew Wilcox , HORIGUCHI NAOYA , "Aneesh Kumar K . V" , Waiman Long , Peter Xu , Mina Almasry , Andrew Morton Subject: Re: [RFC PATCH 3/8] hugetlb: create remove_hugetlb_page() to separate functionality Message-ID: References: <20210319224209.150047-1-mike.kravetz@oracle.com> <20210319224209.150047-4-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210319224209.150047-4-mike.kravetz@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 19-03-21 15:42:04, Mike Kravetz wrote: > The new remove_hugetlb_page() routine is designed to remove a hugetlb > page from hugetlbfs processing. It will remove the page from the active > or free list, update global counters and set the compound page > destructor to NULL so that PageHuge() will return false for the 'page'. > After this call, the 'page' can be treated as a normal compound page or > a collection of base size pages. > > remove_hugetlb_page is to be called with the hugetlb_lock held. > > Creating this routine and separating functionality is in preparation for > restructuring code to reduce lock hold times. I like this! Counters handling both in __free_huge_page and update_and_free_page is really confusing. > Signed-off-by: Mike Kravetz > --- > mm/hugetlb.c | 70 ++++++++++++++++++++++++++++++++++------------------ > 1 file changed, 46 insertions(+), 24 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index c537274c2a38..ae185d3315e0 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1306,6 +1306,46 @@ static inline void destroy_compound_gigantic_page(struct page *page, > unsigned int order) { } > #endif > > +/* > + * Remove hugetlb page from lists, and update dtor so that page appears > + * as just a compound page. A reference is held on the page. > + * NOTE: hugetlb specific page flags stored in page->private are not > + * automatically cleared. These flags may be used in routines > + * which operate on the resulting compound page. > + * > + * Must be called with hugetlb lock held. > + */ > +static void remove_hugetlb_page(struct hstate *h, struct page *page, > + bool adjust_surplus) > +{ > + int nid = page_to_nid(page); > + I think we want lockdep_assert_held here. Lockdep asserts are not used in this code but now that you are touching it then it is probably better to start adding them. What do you think? > + if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) > + return; > + > + list_del(&page->lru); > + > + if (HPageFreed(page)) { > + h->free_huge_pages--; > + h->free_huge_pages_node[nid]--; > + ClearHPageFreed(page); > + } > + if (adjust_surplus) { > + h->surplus_huge_pages--; > + h->surplus_huge_pages_node[nid]--; > + } > + > + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); > + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page); > + > + ClearHPageTemporary(page); > + set_page_refcounted(page); > + set_compound_page_dtor(page, NULL_COMPOUND_DTOR); > + > + h->nr_huge_pages--; > + h->nr_huge_pages_node[nid]--; > +} -- Michal Hocko SUSE Labs