Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752989AbdHNJ4t (ORCPT ); Mon, 14 Aug 2017 05:56:49 -0400 Received: from outboundhk.mxmail.xiaomi.com ([207.226.244.123]:32870 "EHLO xiaomi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752817AbdHNJ4s (ORCPT ); Mon, 14 Aug 2017 05:56:48 -0400 From: Hui Zhu To: , , , , CC: , Hui Zhu Subject: [PATCH v2] zsmalloc: zs_page_migrate: schedule free_work if zspage is ZS_EMPTY Date: Mon, 14 Aug 2017 17:56:30 +0800 Message-ID: <1502704590-3129-1-git-send-email-zhuhui@xiaomi.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.235.171.194] X-ClientProxiedBy: CNCAS3.mioffice.cn (10.237.8.133) To cnbox6.mioffice.cn (10.237.8.146) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1963 Lines: 53 After commit e2846124f9a2 ("zsmalloc: zs_page_migrate: skip unnecessary loops but not return -EBUSY if zspage is not inuse") zs_page_migrate can handle the ZS_EMPTY zspage. But I got some false in zs_page_isolate: if (get_zspage_inuse(zspage) == 0) { spin_unlock(&class->lock); return false; } The page of this zspage was migrated in before. The reason is commit e2846124f9a2 ("zsmalloc: zs_page_migrate: skip unnecessary loops but not return -EBUSY if zspage is not inuse") just handle the "page" but not "newpage" then it keep the "newpage" with a empty zspage inside system. Root cause is zs_page_isolate remove it from ZS_EMPTY list but not call zs_page_putback "schedule_work(&pool->free_work);". Because zs_page_migrate done the job without "schedule_work(&pool->free_work);" Make this patch let zs_page_migrate wake up free_work if need. Fixes: e2846124f9a2 ("zsmalloc: zs_page_migrate: skip unnecessary loops but not return -EBUSY if zspage is not inuse") Signed-off-by: Hui Zhu --- mm/zsmalloc.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 62457eb..c6cc77c 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -2035,8 +2035,17 @@ int zs_page_migrate(struct address_space *mapping, struct page *newpage, * Page migration is done so let's putback isolated zspage to * the list if @page is final isolated subpage in the zspage. */ - if (!is_zspage_isolated(zspage)) - putback_zspage(class, zspage); + if (!is_zspage_isolated(zspage)) { + /* + * Page will be freed in following part. But newpage and + * zspage will stay in system if zspage is in ZS_EMPTY + * list. So call free_work to free it. + * The page and class is locked, we cannot free zspage + * immediately so let's defer. + */ + if (putback_zspage(class, zspage) == ZS_EMPTY) + schedule_work(&pool->free_work); + } reset_page(page); put_page(page); -- 1.9.1