From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f48.google.com (mail-la0-f48.google.com [209.85.215.48]) by kanga.kvack.org (Postfix) with ESMTP id AF96E2802F6 for ; Thu, 16 Jul 2015 13:13:41 -0400 (EDT) Received: by lahh5 with SMTP id h5so47380343lah.2 for ; Thu, 16 Jul 2015 10:13:40 -0700 (PDT) Received: from mail-la0-x236.google.com (mail-la0-x236.google.com. [2a00:1450:4010:c03::236]) by mx.google.com with ESMTPS id u7si2323536lae.3.2015.07.16.10.13.39 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Jul 2015 10:13:39 -0700 (PDT) Received: by lahh5 with SMTP id h5so47379780lah.2 for ; Thu, 16 Jul 2015 10:13:39 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20150714103108.GA6812@suse.de> References: <20150714000910.GA8160@wfg-t540p.sh.intel.com> <20150714103108.GA6812@suse.de> Date: Thu, 16 Jul 2015 20:13:38 +0300 Message-ID: Subject: Re: [mminit] [ INFO: possible recursive locking detected ] From: Konstantin Khlebnikov Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Fengguang Wu , Andrew Morton , Peter Zijlstra , nicstange@gmail.com, Linux Memory Management List , Linux Kernel Mailing List , LKP On Tue, Jul 14, 2015 at 1:31 PM, Mel Gorman wrote: > On Tue, Jul 14, 2015 at 08:09:10AM +0800, Fengguang Wu wrote: >> Greetings, >> >> 0day kernel testing robot got the below dmesg and the first bad commit is >> >> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >> > > Can you check if this patch addresses the problem please? > > ---8<--- > mm, meminit: replace rwsem with completion > > From: Nicolai Stange > > Commit 0e1cc95b4cc7 ("mm: meminit: finish initialisation of struct pages > before basic setup") introduced a rwsem to signal completion of the > initialization workers. > > Lockdep complains about possible recursive locking: > ============================================= > [ INFO: possible recursive locking detected ] > 4.1.0-12802-g1dc51b8 #3 Not tainted > --------------------------------------------- > swapper/0/1 is trying to acquire lock: > (pgdat_init_rwsem){++++.+}, > at: [] page_alloc_init_late+0xc7/0xe6 > > but task is already holding lock: > (pgdat_init_rwsem){++++.+}, > at: [] page_alloc_init_late+0x3e/0xe6 > > Replace the rwsem by a completion together with an atomic > "outstanding work counter". > > [peterz@infradead.org: Barrier removal on the grounds of being pointless] > [mgorman@suse.de: Applied review feedback] > Signed-off-by: Nicolai Stange > Signed-off-by: Mel Gorman > --- > mm/page_alloc.c | 22 +++++++++++++++------- > 1 file changed, 15 insertions(+), 7 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 506eac8b38af..a69e78c396a0 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -18,7 +18,6 @@ > #include > #include > #include > -#include > #include > #include > #include > @@ -1062,7 +1061,15 @@ static void __init deferred_free_range(struct page *page, > __free_pages_boot_core(page, pfn, 0); > } > > -static __initdata DECLARE_RWSEM(pgdat_init_rwsem); > +/* Completion tracking for deferred_init_memmap() threads */ > +static atomic_t pgdat_init_n_undone __initdata; > +static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp); > + > +static inline void __init pgdat_init_report_one_done(void) > +{ > + if (atomic_dec_and_test(&pgdat_init_n_undone)) > + complete(&pgdat_init_all_done_comp); > +} > > /* Initialise remaining memory on a node */ > static int __init deferred_init_memmap(void *data) > @@ -1079,7 +1086,7 @@ static int __init deferred_init_memmap(void *data) > const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); > > if (first_init_pfn == ULONG_MAX) { > - up_read(&pgdat_init_rwsem); > + pgdat_init_report_one_done(); > return 0; > } > > @@ -1179,7 +1186,8 @@ free_range: > > pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages, > jiffies_to_msecs(jiffies - start)); > - up_read(&pgdat_init_rwsem); > + > + pgdat_init_report_one_done(); > return 0; > } > > @@ -1187,14 +1195,14 @@ void __init page_alloc_init_late(void) > {pgdat_init_rwsempgdat_init_rwsempgdat_init_rwsem > int nid; > > + /* There will be num_node_state(N_MEMORY) threads */ > + atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY)); > for_each_node_state(nid, N_MEMORY) { > - down_read(&pgdat_init_rwsem); Rw-sem have special "non-owner" mode for keeping lockdep away. This should be enough: --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1079,7 +1079,7 @@ static int __init deferred_init_memmap(void *data) const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1079,7 +1079,7 @@ static int __init deferred_init_memmap(void *data) const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); if (first_init_pfn == ULONG_MAX) { - up_read(&pgdat_init_rwsem); + up_read_non_owner(&pgdat_init_rwsem); return 0; } @@ -1179,7 +1179,7 @@ free_range: pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages, jiffies_to_msecs(jiffies - start)); - up_read(&pgdat_init_rwsem); + up_read_non_owner(&pgdat_init_rwsem); return 0; } @@ -1188,7 +1188,7 @@ void __init page_alloc_init_late(void) int nid; for_each_node_state(nid, N_MEMORY) { - down_read(&pgdat_init_rwsem); + down_read_non_owner(&pgdat_init_rwsem); kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid); } if (first_init_pfn == ULONG_MAX) { - up_read(&pgdat_init_rwsem); + up_read_non_owner(&pgdat_init_rwsem); return 0; } @@ -1179,7 +1179,7 @@ free_range: pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages, jiffies_to_msecs(jiffies - start)); - up_read(&pgdat_init_rwsem); + up_read_non_owner(&pgdat_init_rwsem); return 0; } @@ -1188,7 +1188,7 @@ void __init page_alloc_init_late(void) int nid; for_each_node_state(nid, N_MEMORY) { - down_read(&pgdat_init_rwsem); + down_read_non_owner(&pgdat_init_rwsem); kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid); } > kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid); > } > > /* Block until all are initialised */ > - down_write(&pgdat_init_rwsem); > - up_write(&pgdat_init_rwsem); > + wait_for_completion(&pgdat_init_all_done_comp); > } > #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org