From patchwork Wed Jan 17 20:21:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Matthew Wilcox (Oracle)" X-Patchwork-Id: 10171173 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6030F603B5 for ; Wed, 17 Jan 2018 20:40:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5325022701 for ; Wed, 17 Jan 2018 20:40:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 472F6237F1; Wed, 17 Jan 2018 20:40:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A664B223B3 for ; Wed, 17 Jan 2018 20:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754605AbeAQUja (ORCPT ); Wed, 17 Jan 2018 15:39:30 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:38269 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753793AbeAQUWy (ORCPT ); Wed, 17 Jan 2018 15:22:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=rTshG3SBn8CWiawm3Q3Mh1fF4HgInl4fH0Vr6jnt6Uk=; b=ZJH5TeDIyWaN0VgN+Y/gTecoM e75Rz3apmCk2dYpeSBVxjwttPvfkQU7HG0rQ/LOfguMqxFwP+1vuKzTcNhFXlqMCKFsBLB+qopUcr c+8QpztKprkDhi47UGhCav1zN23SAjtnjV8UrLF8g42AIPxzys5ut75MX5DRw9HGv5rbk3Ssc0nfJ hx1vPAFQEjY438bOtwWpz/b19Zb49dEK5tPMGjkmMYw8TH1gRQxhaVejSjeuKWcLD0SMR0v09mOvw Rbt30nKvMeIzxMr7cHmCISScw/tkqg0ibI5JIictnc0ZvNfzUU9EAK6/EU5uuEjOkwqmQ9g37CCkg 7XiZ+qh1g==; Received: from willy by bombadil.infradead.org with local (Exim 4.89 #1 (Red Hat Linux)) id 1ebuEX-00067w-Ci; Wed, 17 Jan 2018 20:22:53 +0000 From: Matthew Wilcox To: linux-kernel@vger.kernel.org Cc: Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-usb@vger.kernel.org, Bjorn Andersson , Stefano Stabellini , iommu@lists.linux-foundation.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, intel-gfx@lists.freedesktop.org, cgroups@vger.kernel.org, linux-sh@vger.kernel.org, David Howells Subject: [PATCH v6 67/99] mm: Convert cgroup writeback to XArray Date: Wed, 17 Jan 2018 12:21:31 -0800 Message-Id: <20180117202203.19756-68-willy@infradead.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180117202203.19756-1-willy@infradead.org> References: <20180117202203.19756-1-willy@infradead.org> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Matthew Wilcox This is a fairly naive conversion, leaving in place the GFP_ATOMIC allocation. By switching the locking around, we could use GFP_KERNEL and probably simplify the error handling. Signed-off-by: Matthew Wilcox --- include/linux/backing-dev-defs.h | 2 +- include/linux/backing-dev.h | 2 +- mm/backing-dev.c | 22 ++++++++++------------ 3 files changed, 12 insertions(+), 14 deletions(-) diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index bfe86b54f6c1..074a54aad33c 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -187,7 +187,7 @@ struct backing_dev_info { struct bdi_writeback wb; /* the root writeback info for this bdi */ struct list_head wb_list; /* list of all wbs */ #ifdef CONFIG_CGROUP_WRITEBACK - struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */ + struct xarray cgwb_xa; /* radix tree of active cgroup wbs */ struct rb_root cgwb_congested_tree; /* their congested states */ #else struct bdi_writeback_congested *wb_congested; diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 3df0d20e23f3..27e7b31bd802 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -271,7 +271,7 @@ static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi if (!memcg_css->parent) return &bdi->wb; - wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); + wb = xa_load(&bdi->cgwb_xa, memcg_css->id); /* * %current's blkcg equals the effective blkcg of its memcg. No diff --git a/mm/backing-dev.c b/mm/backing-dev.c index b5f940ce0143..aa0f85df0928 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -417,8 +417,8 @@ static void wb_exit(struct bdi_writeback *wb) #include /* - * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree, - * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_tree is also RCU + * cgwb_lock protects bdi->cgwb_xa, bdi->cgwb_congested_tree, + * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_xa is also RCU * protected. */ static DEFINE_SPINLOCK(cgwb_lock); @@ -539,7 +539,7 @@ static void cgwb_kill(struct bdi_writeback *wb) { lockdep_assert_held(&cgwb_lock); - WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id)); + WARN_ON(xa_erase(&wb->bdi->cgwb_xa, wb->memcg_css->id) != wb); list_del(&wb->memcg_node); list_del(&wb->blkcg_node); percpu_ref_kill(&wb->refcnt); @@ -571,7 +571,7 @@ static int cgwb_create(struct backing_dev_info *bdi, /* look up again under lock and discard on blkcg mismatch */ spin_lock_irqsave(&cgwb_lock, flags); - wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); + wb = xa_load(&bdi->cgwb_xa, memcg_css->id); if (wb && wb->blkcg_css != blkcg_css) { cgwb_kill(wb); wb = NULL; @@ -614,8 +614,7 @@ static int cgwb_create(struct backing_dev_info *bdi, spin_lock_irqsave(&cgwb_lock, flags); if (test_bit(WB_registered, &bdi->wb.state) && blkcg_cgwb_list->next && memcg_cgwb_list->next) { - /* we might have raced another instance of this function */ - ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb); + ret = xa_insert(&bdi->cgwb_xa, memcg_css->id, wb, GFP_ATOMIC); if (!ret) { list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list); list_add(&wb->memcg_node, memcg_cgwb_list); @@ -682,7 +681,7 @@ struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, do { rcu_read_lock(); - wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); + wb = xa_load(&bdi->cgwb_xa, memcg_css->id); if (wb) { struct cgroup_subsys_state *blkcg_css; @@ -704,7 +703,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi) { int ret; - INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC); + xa_init(&bdi->cgwb_xa); bdi->cgwb_congested_tree = RB_ROOT; ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL); @@ -717,15 +716,14 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi) static void cgwb_bdi_unregister(struct backing_dev_info *bdi) { - struct radix_tree_iter iter; - void **slot; + XA_STATE(xas, &bdi->cgwb_xa, 0); struct bdi_writeback *wb; WARN_ON(test_bit(WB_registered, &bdi->wb.state)); spin_lock_irq(&cgwb_lock); - radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0) - cgwb_kill(*slot); + xas_for_each(&xas, wb, ULONG_MAX) + cgwb_kill(wb); while (!list_empty(&bdi->wb_list)) { wb = list_first_entry(&bdi->wb_list, struct bdi_writeback,