Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751397Ab3GSEE5 (ORCPT ); Fri, 19 Jul 2013 00:04:57 -0400 Received: from mail-ob0-f181.google.com ([209.85.214.181]:51831 "EHLO mail-ob0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750782Ab3GSEE4 (ORCPT ); Fri, 19 Jul 2013 00:04:56 -0400 MIME-Version: 1.0 In-Reply-To: <1374203899-w7jwqowi-mutt-n-horiguchi@ah.jp.nec.com> References: <1374183272-10153-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1374183272-10153-2-git-send-email-n-horiguchi@ah.jp.nec.com> <1374203899-w7jwqowi-mutt-n-horiguchi@ah.jp.nec.com> Date: Fri, 19 Jul 2013 12:04:56 +0800 Message-ID: Subject: Re: [PATCH 1/8] migrate: make core migration code aware of hugepage From: Hillf Danton To: Naoya Horiguchi Cc: linux-mm@kvack.org, Andrew Morton , Mel Gorman , Hugh Dickins , KOSAKI Motohiro , Andi Kleen , Michal Hocko , Rik van Riel , "Aneesh Kumar K.V" , linux-kernel@vger.kernel.org, Naoya Horiguchi Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2603 Lines: 64 On Fri, Jul 19, 2013 at 11:18 AM, Naoya Horiguchi wrote: >> > +bool isolate_huge_page(struct page *page, struct list_head *l) >> >> Can we replace the page parameter with p? > > Yes. Maybe it's strange to use the full name "page" for one parameter > and an extremely shortened one "l" for another one. > Actually i mean the l arg could be replaced with something else ;) >> > + >> > +void putback_active_hugepage(struct page *page) >> > +{ >> > + VM_BUG_ON(!PageHead(page)); >> > + spin_lock(&hugetlb_lock); >> > + list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); >> > + spin_unlock(&hugetlb_lock); >> > + put_page(page); >> > +} >> > + >> > +void putback_active_hugepages(struct list_head *l) >> > +{ >> > + struct page *page; >> > + struct page *page2; >> > + >> > + list_for_each_entry_safe(page, page2, l, lru) >> > + putback_active_hugepage(page); >> >> Can we acquire hugetlb_lock only once? > > I'm not sure which is the best. In general, fine-grained locking is > preferred because other lock contenders wait less. > Could you tell some specific reason to hold lock outside the loop? > No anything special, looks we can do list splice after taking lock, then we no longer contend it. >> > @@ -1025,7 +1029,11 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >> > list_for_each_entry_safe(page, page2, from, lru) { >> > cond_resched(); >> > >> > - rc = unmap_and_move(get_new_page, private, >> > + if (PageHuge(page)) >> > + rc = unmap_and_move_huge_page(get_new_page, >> > + private, page, pass > 2, mode); >> > + else >> > + rc = unmap_and_move(get_new_page, private, >> > page, pass > 2, mode); >> > >> Is this hunk unclean merge? > > Sorry, I don't catch the point. This patch is based on v3.11-rc1 and > the present HEAD has no changes from that release. > Or do you mean that other trees have some conflicts? (my brief checking > on -mm/-next didn't find that...) > Looks this hunk should appear in 2/8 or later, as 1/8 is focusing on hugepage->lru? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/