From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com (mail-io0-f197.google.com [209.85.223.197]) by kanga.kvack.org (Postfix) with ESMTP id 1D4676B0033 for ; Mon, 23 Jan 2017 07:45:38 -0500 (EST) Received: by mail-io0-f197.google.com with SMTP id v96so150691400ioi.5 for ; Mon, 23 Jan 2017 04:45:38 -0800 (PST) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [58.251.152.64]) by mx.google.com with ESMTPS id w13si13696347iow.157.2017.01.23.04.45.35 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 23 Jan 2017 04:45:37 -0800 (PST) Subject: Re: [RFC v2] HWPOISON: soft offlining for non-lru movable page References: <1484837943-21745-1-git-send-email-ysxie@foxmail.com> <20170123051459.GB11763@bbox> From: Yisheng Xie Message-ID: Date: Mon, 23 Jan 2017 20:39:59 +0800 MIME-Version: 1.0 In-Reply-To: <20170123051459.GB11763@bbox> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim , ysxie@foxmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, n-horiguchi@ah.jp.nec.com, mhocko@suse.com, akpm@linux-foundation.org, vbabka@suse.cz, guohanjun@huawei.com, qiuxishi@huawei.com Hi Minchan, Thanks for reviewing. On 2017/1/23 13:14, Minchan Kim wrote: > Hello, > > On Thu, Jan 19, 2017 at 10:59:03PM +0800, ysxie@foxmail.com wrote: >> From: Yisheng Xie >> >> @@ -1527,7 +1527,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags) >> { >> int ret = __get_any_page(page, pfn, flags); >> >> - if (ret == 1 && !PageHuge(page) && !PageLRU(page)) { >> + if (ret == 1 && !PageHuge(page) && >> + !PageLRU(page) && !__PageMovable(page)) { > > __PageMovable without holding page_lock could be raced so need to check > if it's okay to miss some of pages offlining by the race. > When I read description of soft_offline_page, it seems to be okay. > Just wanted double check. :) Yes, I have thought about whether should add page_lock to avoid race. For it is ok to miss some of pages caused by race, I do not add page_lock. > >> /* >> * Try to free it. >> */ >> @@ -1609,7 +1610,7 @@ static int soft_offline_huge_page(struct page *page, int flags) >> >> static int __soft_offline_page(struct page *page, int flags) >> { >> - int ret; >> + int ret = -1; >> unsigned long pfn = page_to_pfn(page); >> >> /* >> @@ -1619,7 +1620,8 @@ static int __soft_offline_page(struct page *page, int flags) >> * so there's no race between soft_offline_page() and memory_failure(). >> */ >> lock_page(page); >> - wait_on_page_writeback(page); >> + if (PageLRU(page)) >> + wait_on_page_writeback(page); > > I doubt we need to add such limitation(i.e., Only LRU pages could be write-backed). > Do you have some reason to add that code? I add this check for not quite sure about whether non-lru page will as marked as PageWriteBack(page). I will delete no need limitation in next version. > >> if (PageHWPoison(page)) { >> unlock_page(page); >> put_hwpoison_page(page); >> @@ -1630,7 +1632,8 @@ static int __soft_offline_page(struct page *page, int flags) >> * Try to invalidate first. This should work for >> * non dirty unmapped page cache pages. >> */ >> - ret = invalidate_inode_page(page); >> + if (PageLRU(page)) >> + ret = invalidate_inode_page(page); > > Ditto. > >> unlock_page(page); >> /* >> * RED-PEN would be better to keep it isolated here, but we >> @@ -1649,7 +1652,10 @@ static int __soft_offline_page(struct page *page, int flags) >> * Try to migrate to a new page instead. migrate.c >> * handles a large number of cases for us. >> */ >> - ret = isolate_lru_page(page); >> + if (PageLRU(page)) >> + ret = isolate_lru_page(page); >> + else >> + ret = !isolate_movable_page(page, ISOLATE_UNEVICTABLE); >> /* >> * Drop page reference which is came from get_any_page() >> * successful isolate_lru_page() already took another one. >> @@ -1657,18 +1663,15 @@ static int __soft_offline_page(struct page *page, int flags) >> put_hwpoison_page(page); >> if (!ret) { >> LIST_HEAD(pagelist); >> - inc_node_page_state(page, NR_ISOLATED_ANON + >> + if (PageLRU(page)) > > isolate_lru_page removes PG_lru so this check will be false. Namely, happens > isolated count mismatch happens. > Really sorry about that. That's my mistake. I will use !__PageMovable(page) instead in v3. Thanks Yisheng Xie. -- 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