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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 1F7B8C282C2 for ; Wed, 13 Feb 2019 03:25:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E957C21B1A for ; Wed, 13 Feb 2019 03:25:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730088AbfBMDZW (ORCPT ); Tue, 12 Feb 2019 22:25:22 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:3193 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727346AbfBMDZV (ORCPT ); Tue, 12 Feb 2019 22:25:21 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 2011EF1FBB5C16EC2E4D; Wed, 13 Feb 2019 11:25:20 +0800 (CST) Received: from [127.0.0.1] (10.134.22.195) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.408.0; Wed, 13 Feb 2019 11:25:19 +0800 Subject: Re: [PATCH] f2fs: do not use mutex lock in atomic context To: Sahitya Tummala , Jaegeuk Kim , CC: References: <1549267613-9288-1-git-send-email-stummala@codeaurora.org> From: Chao Yu Message-ID: Date: Wed, 13 Feb 2019 11:25:31 +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: <1549267613-9288-1-git-send-email-stummala@codeaurora.org> 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 2019/2/4 16:06, Sahitya Tummala wrote: > Fix below warning coming because of using mutex lock in atomic context. > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:98 > in_atomic(): 1, irqs_disabled(): 0, pid: 585, name: sh > Preemption disabled at: __radix_tree_preload+0x28/0x130 > Call trace: > dump_backtrace+0x0/0x2b4 > show_stack+0x20/0x28 > dump_stack+0xa8/0xe0 > ___might_sleep+0x144/0x194 > __might_sleep+0x58/0x8c > mutex_lock+0x2c/0x48 > f2fs_trace_pid+0x88/0x14c > f2fs_set_node_page_dirty+0xd0/0x184 > > Do not use f2fs_radix_tree_insert() to avoid doing cond_resched() with > spin_lock() acquired. > > Signed-off-by: Sahitya Tummala > --- > fs/f2fs/trace.c | 20 +++++++++++++------- > 1 file changed, 13 insertions(+), 7 deletions(-) > > diff --git a/fs/f2fs/trace.c b/fs/f2fs/trace.c > index ce2a5eb..d0ab533 100644 > --- a/fs/f2fs/trace.c > +++ b/fs/f2fs/trace.c > @@ -14,7 +14,7 @@ > #include "trace.h" > > static RADIX_TREE(pids, GFP_ATOMIC); > -static struct mutex pids_lock; > +static spinlock_t pids_lock; > static struct last_io_info last_io; > > static inline void __print_last_io(void) > @@ -58,23 +58,29 @@ void f2fs_trace_pid(struct page *page) > > set_page_private(page, (unsigned long)pid); > > +retry: > if (radix_tree_preload(GFP_NOFS)) > return; > > - mutex_lock(&pids_lock); > + spin_lock(&pids_lock); > p = radix_tree_lookup(&pids, pid); > if (p == current) > goto out; > if (p) > radix_tree_delete(&pids, pid); > > - f2fs_radix_tree_insert(&pids, pid, current); > + if (radix_tree_insert(&pids, pid, current)) { > + spin_unlock(&pids_lock); > + radix_tree_preload_end(); > + cond_resched(); > + goto retry; > + } > > trace_printk("%3x:%3x %4x %-16s\n", > MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev), > pid, current->comm); Hi Sahitya, Can trace_printk sleep? For safety, how about moving it out of spinlock? Thanks, > out: > - mutex_unlock(&pids_lock); > + spin_unlock(&pids_lock); > radix_tree_preload_end(); > } > > @@ -119,7 +125,7 @@ void f2fs_trace_ios(struct f2fs_io_info *fio, int flush) > > void f2fs_build_trace_ios(void) > { > - mutex_init(&pids_lock); > + spin_lock_init(&pids_lock); > } > > #define PIDVEC_SIZE 128 > @@ -147,7 +153,7 @@ void f2fs_destroy_trace_ios(void) > pid_t next_pid = 0; > unsigned int found; > > - mutex_lock(&pids_lock); > + spin_lock(&pids_lock); > while ((found = gang_lookup_pids(pid, next_pid, PIDVEC_SIZE))) { > unsigned idx; > > @@ -155,5 +161,5 @@ void f2fs_destroy_trace_ios(void) > for (idx = 0; idx < found; idx++) > radix_tree_delete(&pids, pid[idx]); > } > - mutex_unlock(&pids_lock); > + spin_unlock(&pids_lock); > } > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: Re: [PATCH] f2fs: do not use mutex lock in atomic context Date: Wed, 13 Feb 2019 11:25:31 +0800 Message-ID: References: <1549267613-9288-1-git-send-email-stummala@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1549267613-9288-1-git-send-email-stummala@codeaurora.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Sahitya Tummala , Jaegeuk Kim , linux-f2fs-devel@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net On 2019/2/4 16:06, Sahitya Tummala wrote: > Fix below warning coming because of using mutex lock in atomic context. > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:98 > in_atomic(): 1, irqs_disabled(): 0, pid: 585, name: sh > Preemption disabled at: __radix_tree_preload+0x28/0x130 > Call trace: > dump_backtrace+0x0/0x2b4 > show_stack+0x20/0x28 > dump_stack+0xa8/0xe0 > ___might_sleep+0x144/0x194 > __might_sleep+0x58/0x8c > mutex_lock+0x2c/0x48 > f2fs_trace_pid+0x88/0x14c > f2fs_set_node_page_dirty+0xd0/0x184 > > Do not use f2fs_radix_tree_insert() to avoid doing cond_resched() with > spin_lock() acquired. > > Signed-off-by: Sahitya Tummala > --- > fs/f2fs/trace.c | 20 +++++++++++++------- > 1 file changed, 13 insertions(+), 7 deletions(-) > > diff --git a/fs/f2fs/trace.c b/fs/f2fs/trace.c > index ce2a5eb..d0ab533 100644 > --- a/fs/f2fs/trace.c > +++ b/fs/f2fs/trace.c > @@ -14,7 +14,7 @@ > #include "trace.h" > > static RADIX_TREE(pids, GFP_ATOMIC); > -static struct mutex pids_lock; > +static spinlock_t pids_lock; > static struct last_io_info last_io; > > static inline void __print_last_io(void) > @@ -58,23 +58,29 @@ void f2fs_trace_pid(struct page *page) > > set_page_private(page, (unsigned long)pid); > > +retry: > if (radix_tree_preload(GFP_NOFS)) > return; > > - mutex_lock(&pids_lock); > + spin_lock(&pids_lock); > p = radix_tree_lookup(&pids, pid); > if (p == current) > goto out; > if (p) > radix_tree_delete(&pids, pid); > > - f2fs_radix_tree_insert(&pids, pid, current); > + if (radix_tree_insert(&pids, pid, current)) { > + spin_unlock(&pids_lock); > + radix_tree_preload_end(); > + cond_resched(); > + goto retry; > + } > > trace_printk("%3x:%3x %4x %-16s\n", > MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev), > pid, current->comm); Hi Sahitya, Can trace_printk sleep? For safety, how about moving it out of spinlock? Thanks, > out: > - mutex_unlock(&pids_lock); > + spin_unlock(&pids_lock); > radix_tree_preload_end(); > } > > @@ -119,7 +125,7 @@ void f2fs_trace_ios(struct f2fs_io_info *fio, int flush) > > void f2fs_build_trace_ios(void) > { > - mutex_init(&pids_lock); > + spin_lock_init(&pids_lock); > } > > #define PIDVEC_SIZE 128 > @@ -147,7 +153,7 @@ void f2fs_destroy_trace_ios(void) > pid_t next_pid = 0; > unsigned int found; > > - mutex_lock(&pids_lock); > + spin_lock(&pids_lock); > while ((found = gang_lookup_pids(pid, next_pid, PIDVEC_SIZE))) { > unsigned idx; > > @@ -155,5 +161,5 @@ void f2fs_destroy_trace_ios(void) > for (idx = 0; idx < found; idx++) > radix_tree_delete(&pids, pid[idx]); > } > - mutex_unlock(&pids_lock); > + spin_unlock(&pids_lock); > } >