From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B96BECAAA2 for ; Mon, 29 Aug 2022 02:12:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229768AbiH2CMh (ORCPT ); Sun, 28 Aug 2022 22:12:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229553AbiH2CMW (ORCPT ); Sun, 28 Aug 2022 22:12:22 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CF483C8DB for ; Sun, 28 Aug 2022 19:12:18 -0700 (PDT) Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MGDPZ5tDLzkWjQ; Mon, 29 Aug 2022 10:08:34 +0800 (CST) Received: from dggpemm100009.china.huawei.com (7.185.36.113) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 29 Aug 2022 10:12:11 +0800 Received: from [10.174.179.24] (10.174.179.24) by dggpemm100009.china.huawei.com (7.185.36.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 29 Aug 2022 10:12:10 +0800 Subject: Re: [PATCH -next v3 2/5] frontswap: invoke ops->init for online swap device in frontswap_register_ops To: Vitaly Wool References: <20220827104600.1813214-1-liushixin2@huawei.com> <20220827104600.1813214-3-liushixin2@huawei.com> CC: Seth Jennings , Dan Streetman , Andrew Morton , Nathan Chancellor , Christoph Hellwig , , , Kefeng Wang From: Liu Shixin Message-ID: <98b709b5-6a0c-0d6f-0aa7-24c68aaf26aa@huawei.com> Date: Mon, 29 Aug 2022 10:12:10 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.24] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm100009.china.huawei.com (7.185.36.113) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/8/29 4:47, Vitaly Wool wrote: > On Sat, Aug 27, 2022 at 12:12 PM Liu Shixin wrote: >> Since we are supported to delay zswap initializaton, we need to invoke >> ops->init for the swap device which is already online when register >> backend. >> >> This patch is a revert of f328c1d16e4c ("frontswap: simplify frontswap_register_ops") >> and 633423a09cb5 ("mm: mark swap_lock and swap_active_head static") >> >> Signed-off-by: Liu Shixin > Sorry, is this the revert of 2 patches at the same time? I would > rather not do it like that. > > Thanks, > Vitaly Thanks for your advice, I'll split it to two patches and resend it. >> --- >> include/linux/swapfile.h | 2 ++ >> mm/frontswap.c | 47 ++++++++++++++++++++++++++++++++++++++++ >> mm/swapfile.c | 4 ++-- >> 3 files changed, 51 insertions(+), 2 deletions(-) >> >> diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h >> index 2fbcc9afd814..75fc069594a5 100644 >> --- a/include/linux/swapfile.h >> +++ b/include/linux/swapfile.h >> @@ -6,6 +6,8 @@ >> * these were static in swapfile.c but frontswap.c needs them and we don't >> * want to expose them to the dozens of source files that include swap.h >> */ >> +extern spinlock_t swap_lock; >> +extern struct plist_head swap_active_head; >> extern struct swap_info_struct *swap_info[]; >> extern unsigned long generic_max_swapfile_size(void); >> /* Maximum swapfile size supported for the arch (not inclusive). */ >> diff --git a/mm/frontswap.c b/mm/frontswap.c >> index 620f95af81dd..449e6f499b88 100644 >> --- a/mm/frontswap.c >> +++ b/mm/frontswap.c >> @@ -96,11 +96,58 @@ static inline void inc_frontswap_invalidates(void) { } >> */ >> int frontswap_register_ops(const struct frontswap_ops *ops) >> { >> + DECLARE_BITMAP(a, MAX_SWAPFILES); >> + DECLARE_BITMAP(b, MAX_SWAPFILES); >> + struct swap_info_struct *si; >> + unsigned int i; >> + >> if (frontswap_ops) >> return -EINVAL; >> >> + bitmap_zero(a, MAX_SWAPFILES); >> + bitmap_zero(b, MAX_SWAPFILES); >> + >> + spin_lock(&swap_lock); >> + plist_for_each_entry(si, &swap_active_head, list) { >> + if (!WARN_ON(!si->frontswap_map)) >> + __set_bit(si->type, a); >> + } >> + spin_unlock(&swap_lock); >> + >> + /* the new ops needs to know the currently active swap devices */ >> + for_each_set_bit(i, a, MAX_SWAPFILES) { >> + pr_err("init frontswap_ops\n"); >> + ops->init(i); >> + } >> + >> frontswap_ops = ops; >> static_branch_inc(&frontswap_enabled_key); >> + >> + spin_lock(&swap_lock); >> + plist_for_each_entry(si, &swap_active_head, list) { >> + if (si->frontswap_map) >> + __set_bit(si->type, b); >> + } >> + spin_unlock(&swap_lock); >> + >> + /* >> + * On the very unlikely chance that a swap device was added or >> + * removed between setting the "a" list bits and the ops init >> + * calls, we re-check and do init or invalidate for any changed >> + * bits. >> + */ >> + if (unlikely(!bitmap_equal(a, b, MAX_SWAPFILES))) { >> + for (i = 0; i < MAX_SWAPFILES; i++) { >> + if (!test_bit(i, a) && test_bit(i, b)) { >> + pr_err("init frontswap_ops re\n"); >> + ops->init(i); >> + } else if (test_bit(i, a) && !test_bit(i, b)) { >> + pr_err("inval frontswap_ops re\n"); >> + ops->invalidate_area(i); >> + } >> + } >> + } >> + >> return 0; >> } >> >> diff --git a/mm/swapfile.c b/mm/swapfile.c >> index 469d9af86be2..d383b282f269 100644 >> --- a/mm/swapfile.c >> +++ b/mm/swapfile.c >> @@ -51,7 +51,7 @@ static bool swap_count_continued(struct swap_info_struct *, pgoff_t, >> unsigned char); >> static void free_swap_count_continuations(struct swap_info_struct *); >> >> -static DEFINE_SPINLOCK(swap_lock); >> +DEFINE_SPINLOCK(swap_lock); >> static unsigned int nr_swapfiles; >> atomic_long_t nr_swap_pages; >> /* >> @@ -77,7 +77,7 @@ static const char Unused_offset[] = "Unused swap offset entry "; >> * all active swap_info_structs >> * protected with swap_lock, and ordered by priority. >> */ >> -static PLIST_HEAD(swap_active_head); >> +PLIST_HEAD(swap_active_head); >> >> /* >> * all available (active, not full) swap_info_structs >> -- >> 2.25.1 >> > . >