Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751274AbdCMGfT (ORCPT ); Mon, 13 Mar 2017 02:35:19 -0400 Received: from out0-144.mail.aliyun.com ([140.205.0.144]:39453 "EHLO out0-144.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882AbdCMGfM (ORCPT ); Mon, 13 Mar 2017 02:35:12 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e02c03280;MF=hillf.zj@alibaba-inc.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---.7nbC-Or_1489386878; Reply-To: "Hillf Danton" From: "Hillf Danton" To: "'Minchan Kim'" , "'Andrew Morton'" Cc: , , , "'Johannes Weiner'" , "'Michal Hocko'" , "'Kirill A. Shutemov'" , "'Anshuman Khandual'" References: <1489365353-28205-1-git-send-email-minchan@kernel.org> <1489365353-28205-3-git-send-email-minchan@kernel.org> In-Reply-To: <1489365353-28205-3-git-send-email-minchan@kernel.org> Subject: Re: [PATCH v1 02/10] mm: remove SWAP_DIRTY in ttu Date: Mon, 13 Mar 2017 14:34:37 +0800 Message-ID: <099201d29bc3$e3ab2d60$ab018820$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQIV+DCgOBhRPgQllZDFzchoeA2H3wJN4qp9oPkmrWA= Content-Language: zh-cn Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2700 Lines: 82 On March 13, 2017 8:36 AM Minchan Kim wrote: > > If we found lazyfree page is dirty, try_to_unmap_one can just > SetPageSwapBakced in there like PG_mlocked page and just return > with SWAP_FAIL which is very natural because the page is not > swappable right now so that vmscan can activate it. > There is no point to introduce new return value SWAP_DIRTY > in ttu at the moment. > > Acked-by: Kirill A. Shutemov > Signed-off-by: Minchan Kim > --- Acked-by: Hillf Danton > include/linux/rmap.h | 1 - > mm/rmap.c | 6 +++--- > mm/vmscan.c | 3 --- > 3 files changed, 3 insertions(+), 7 deletions(-) > > diff --git a/include/linux/rmap.h b/include/linux/rmap.h > index fee10d7..b556eef 100644 > --- a/include/linux/rmap.h > +++ b/include/linux/rmap.h > @@ -298,6 +298,5 @@ static inline int page_mkclean(struct page *page) > #define SWAP_AGAIN 1 > #define SWAP_FAIL 2 > #define SWAP_MLOCK 3 > -#define SWAP_DIRTY 4 > > #endif /* _LINUX_RMAP_H */ > diff --git a/mm/rmap.c b/mm/rmap.c > index 9dbfa6f..d47af09 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1414,7 +1414,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, > */ > if (unlikely(PageSwapBacked(page) != PageSwapCache(page))) { > WARN_ON_ONCE(1); > - ret = SWAP_FAIL; > + ret = false; Nit: Hm looks like stray merge. Not sure it's really needed. > page_vma_mapped_walk_done(&pvmw); > break; > } > @@ -1431,7 +1431,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, > * discarded. Remap the page to page table. > */ > set_pte_at(mm, address, pvmw.pte, pteval); > - ret = SWAP_DIRTY; > + SetPageSwapBacked(page); > + ret = SWAP_FAIL; > page_vma_mapped_walk_done(&pvmw); > break; > } > @@ -1501,7 +1502,6 @@ static int page_mapcount_is_zero(struct page *page) > * SWAP_AGAIN - we missed a mapping, try again later > * SWAP_FAIL - the page is unswappable > * SWAP_MLOCK - page is mlocked. > - * SWAP_DIRTY - page is dirty MADV_FREE page > */ > int try_to_unmap(struct page *page, enum ttu_flags flags) > { > diff --git a/mm/vmscan.c b/mm/vmscan.c > index a3656f9..b8fd656 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1142,9 +1142,6 @@ static unsigned long shrink_page_list(struct list_head *page_list, > if (page_mapped(page)) { > switch (ret = try_to_unmap(page, > ttu_flags | TTU_BATCH_FLUSH)) { > - case SWAP_DIRTY: > - SetPageSwapBacked(page); > - /* fall through */ > case SWAP_FAIL: > nr_unmap_fail++; > goto activate_locked; > -- > 2.7.4