Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1186078 > unrolled thread
| Started by | Konstantin Khlebnikov <koct9i@gmail.com> |
|---|---|
| First post | 2015-07-16 19:20 +0200 |
| Last post | 2015-07-17 07:10 +0200 |
| Articles | 4 — 3 participants |
Back to article view | Back to linux.kernel
This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by
below is the oldest one visible, not the original post.
Re: [mminit] [ INFO: possible recursive locking detected ] Konstantin Khlebnikov <koct9i@gmail.com> - 2015-07-16 19:20 +0200
Re: [mminit] [ INFO: possible recursive locking detected ] Peter Zijlstra <peterz@infradead.org> - 2015-07-16 19:40 +0200
Re: [mminit] [ INFO: possible recursive locking detected ] Mel Gorman <mgorman@suse.de> - 2015-07-16 20:00 +0200
Re: [mminit] [ INFO: possible recursive locking detected ] Konstantin Khlebnikov <koct9i@gmail.com> - 2015-07-17 07:10 +0200
| From | Konstantin Khlebnikov <koct9i@gmail.com> |
|---|---|
| Date | 2015-07-16 19:20 +0200 |
| Subject | Re: [mminit] [ INFO: possible recursive locking detected ] |
| Message-ID | <pMUZc-4Ke-17@gated-at.bofh.it> |
On Tue, Jul 14, 2015 at 1:31 PM, Mel Gorman <mgorman@suse.de> 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 <nicstange@gmail.com>
>
> 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: [<ffffffff8424c7fb>] page_alloc_init_late+0xc7/0xe6
>
> but task is already holding lock:
> (pgdat_init_rwsem){++++.+},
> at: [<ffffffff8424c772>] 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 <nicstange@gmail.com>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> ---
> 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 <linux/mm.h>
> #include <linux/swap.h>
> #include <linux/interrupt.h>
> -#include <linux/rwsem.h>
> #include <linux/pagemap.h>
> #include <linux/jiffies.h>
> #include <linux/bootmem.h>
> @@ -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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [next] | [standalone]
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Date | 2015-07-16 19:40 +0200 |
| Message-ID | <pMViA-57c-59@gated-at.bofh.it> |
| In reply to | #1186078 |
On Thu, Jul 16, 2015 at 08:13:38PM +0300, Konstantin Khlebnikov wrote: > Rw-sem have special "non-owner" mode for keeping lockdep away. Nooo, no new ones of those please!! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[toc] | [prev] | [next] | [standalone]
| From | Mel Gorman <mgorman@suse.de> |
|---|---|
| Date | 2015-07-16 20:00 +0200 |
| Message-ID | <pMVBU-5ug-21@gated-at.bofh.it> |
| In reply to | #1186078 |
On Thu, Jul 16, 2015 at 08:13:38PM +0300, Konstantin Khlebnikov wrote:
> > @@ -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:
>
I think in this case that the completions look nicer though so I think
I'll keep them.
--
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [prev] | [next] | [standalone]
| From | Konstantin Khlebnikov <koct9i@gmail.com> |
|---|---|
| Date | 2015-07-17 07:10 +0200 |
| Message-ID | <pN64h-41z-1@gated-at.bofh.it> |
| In reply to | #1186160 |
On Thu, Jul 16, 2015 at 8:51 PM, Mel Gorman <mgorman@suse.de> wrote:
> On Thu, Jul 16, 2015 at 08:13:38PM +0300, Konstantin Khlebnikov wrote:
>> > @@ -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:
>>
>
> I think in this case that the completions look nicer though so I think
> I'll keep them.
Ok. Not a big deal, they are anyway in init sections.
BTW there's another option: wait_on_atomic_t / wake_up_atomic_t
like wait_on_bit but atomic_t
>
> --
> Mel Gorman
> SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web