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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 BAB80C38A2A for ; Thu, 7 May 2020 12:49:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E5E12084D for ; Thu, 7 May 2020 12:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588855761; bh=31pqcdlKcDRpHUSplqujtBg+s8YvDSiNTvR/6s8xihQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=1p1x6BOAwiUVfVYTd9oEt7Pf1TtVADR/efJDTEFgKpuNSeBhIgZbS8Swg9a82IBL4 9qYHbpjCPu6fbb9P/ITDkVDuSwMk0+OXrkL/App4+ztKLvvbJFjEMfpMk8Xs5EA3mE TgWeJn/OVruXz740IKpnOwnHzQF/4IFM/UDfpaLY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726467AbgEGMtU (ORCPT ); Thu, 7 May 2020 08:49:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:35260 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725939AbgEGMtU (ORCPT ); Thu, 7 May 2020 08:49:20 -0400 Received: from localhost (unknown [104.132.1.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AFF5C2063A; Thu, 7 May 2020 12:49:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588855759; bh=31pqcdlKcDRpHUSplqujtBg+s8YvDSiNTvR/6s8xihQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vfNqKzqGfJYbM7KCZSAyfWsclW0AoCBnVvcFi0AE1zUrGQ9rVX4RZbD+wUPBOXIqN +z0ml/tT9SmT6DJaxsc3G+dnf030lQ7Lp+KFs0pT/gzFp3WC8zCF8EB8YC1TtpmIhu nN4evojy8b5/nvc6c7k0Kzzbs2zSUqyl/QFvqnvs= Date: Thu, 7 May 2020 05:49:19 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, chao@kernel.org Subject: Re: [PATCH v2] f2fs: shrink spinlock coverage Message-ID: <20200507124919.GA197114@google.com> References: <20200506104542.123575-1-yuchao0@huawei.com> <20200506150521.GE107238@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/07, Chao Yu wrote: > 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? Yes. > > 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 > > . > >