From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f43.google.com (mail-pa0-f43.google.com [209.85.220.43]) by kanga.kvack.org (Postfix) with ESMTP id 926226B0256 for ; Tue, 13 Oct 2015 05:10:09 -0400 (EDT) Received: by pabrc13 with SMTP id rc13so15981856pab.0 for ; Tue, 13 Oct 2015 02:10:09 -0700 (PDT) Received: from us-alimail-mta2.hst.scl.en.alidc.net (mail113-249.mail.alibaba.com. [205.204.113.249]) by mx.google.com with ESMTP id fd1si3720726pad.44.2015.10.13.02.10.07 for ; Tue, 13 Oct 2015 02:10:08 -0700 (PDT) Reply-To: "Hillf Danton" From: "Hillf Danton" References: <004b01d10596$60e7eae0$22b7c0a0$@alibaba-inc.com> In-Reply-To: <004b01d10596$60e7eae0$22b7c0a0$@alibaba-inc.com> Subject: Re: [PATCH] hugetlb: clear PG_reserved before setting PG_head on gigantic pages Date: Tue, 13 Oct 2015 17:09:52 +0800 Message-ID: <004e01d10596$eba6de70$c2f49b50$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , Sasha Levin Cc: Andrew Morton , linux-kernel , linux-mm@kvack.org > PF_NO_COMPOUND for PG_reserved assumes we don't use PG_reserved for > compound pages. And we generally don't. But during allocation of > gigantic pages we set PG_head before clearing PG_reserved and > __ClearPageReserved() steps on the VM_BUG_ON_PAGE(). > > The fix is trivial: set PG_head after PG_reserved. > > Signed-off-by: Kirill A. Shutemov > Reported-by: Sasha Levin > --- Acked-by: Hillf Danton > > Andrew, this patch can be folded into "page-flags: define PG_reserved behavior on compound pages". > > --- > mm/hugetlb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 6ecf61ffa65d..bd3f3e20313b 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1258,8 +1258,8 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order) > > /* we rely on prep_new_huge_page to set the destructor */ > set_compound_order(page, order); > - __SetPageHead(page); > __ClearPageReserved(page); > + __SetPageHead(page); > for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { > /* > * For gigantic hugepages allocated through bootmem at > -- > 2.5.3 > -- 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