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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C95EC28CBC for ; Thu, 7 May 2020 03:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 493732068E for ; Thu, 7 May 2020 03:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728447AbgEGDDf (ORCPT ); Wed, 6 May 2020 23:03:35 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:3830 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726437AbgEGDDf (ORCPT ); Wed, 6 May 2020 23:03:35 -0400 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 0FB04998E81665E6A654; Thu, 7 May 2020 11:03:30 +0800 (CST) Received: from [10.134.22.195] (10.134.22.195) by smtp.huawei.com (10.3.19.201) with Microsoft SMTP Server (TLS) id 14.3.487.0; Thu, 7 May 2020 11:03:28 +0800 Subject: Re: [PATCH v2] f2fs: shrink spinlock coverage To: Jaegeuk Kim CC: , , References: <20200506104542.123575-1-yuchao0@huawei.com> <20200506150521.GE107238@google.com> From: Chao Yu Message-ID: Date: Thu, 7 May 2020 11:03:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200506150521.GE107238@google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/5/6 23:05, Jaegeuk Kim wrote: > On 05/06, Chao Yu wrote: >> In f2fs_try_to_free_nids(), .nid_list_lock spinlock critical region will >> increase as expected shrink number increase, to avoid spining other CPUs >> for long time, it's better to implement like extent cache and nats >> shrinker. >> >> Signed-off-by: Chao Yu >> --- >> v2: >> - fix unlock wrong spinlock. >> fs/f2fs/node.c | 15 +++++++++++---- >> 1 file changed, 11 insertions(+), 4 deletions(-) >> >> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c >> index 4da0d8713df5..ad0b14f4dab8 100644 >> --- a/fs/f2fs/node.c >> +++ b/fs/f2fs/node.c >> @@ -2488,7 +2488,6 @@ void f2fs_alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid) >> int f2fs_try_to_free_nids(struct f2fs_sb_info *sbi, int nr_shrink) >> { >> struct f2fs_nm_info *nm_i = NM_I(sbi); >> - struct free_nid *i, *next; >> int nr = nr_shrink; >> >> if (nm_i->nid_cnt[FREE_NID] <= MAX_FREE_NIDS) >> @@ -2498,14 +2497,22 @@ int f2fs_try_to_free_nids(struct f2fs_sb_info *sbi, int nr_shrink) >> return 0; >> >> spin_lock(&nm_i->nid_list_lock); >> - list_for_each_entry_safe(i, next, &nm_i->free_nid_list, list) { >> - if (nr_shrink <= 0 || >> - nm_i->nid_cnt[FREE_NID] <= MAX_FREE_NIDS) >> + while (nr_shrink) { >> + struct free_nid *i; >> + >> + if (nm_i->nid_cnt[FREE_NID] <= MAX_FREE_NIDS) >> break; >> >> + i = list_first_entry(&nm_i->free_nid_list, >> + struct free_nid, list); >> + list_del(&i->list); >> + spin_unlock(&nm_i->nid_list_lock); >> + >> __remove_free_nid(sbi, i, FREE_NID); > > __remove_free_nid() will do list_del again. btw, how about just splitting out Oh, my bad. How about moving __remove_free_nid into .nid_list_lock coverage? > given nr_shrink into multiple trials? Like this? while (shrink) { batch = DEFAULT_BATCH_NUMBER; // 16 spinlock(); list_for_each_entry_safe() { if (!shrink || !batch) break; remove_item_from_list; shrink--; batch--; } spin_unlock(); } Thanks, > >> kmem_cache_free(free_nid_slab, i); >> nr_shrink--; >> + >> + spin_lock(&nm_i->nid_list_lock); >> } >> spin_unlock(&nm_i->nid_list_lock); >> mutex_unlock(&nm_i->build_lock); >> -- >> 2.18.0.rc1 > . >