From: Peter Zijlstra <peterz@infradead.org>
To: Byungchul Park <byungchul.park@lge.com>
Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com,
boqun.feng@gmail.com, kirill@shutemov.name,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
npiggin@gmail.com
Subject: Re: [PATCH v4 06/15] lockdep: Make save_trace can skip stack tracing of the current
Date: Thu, 12 Jan 2017 17:37:57 +0100 [thread overview]
Message-ID: <20170112163757.GC3144@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1481260331-360-7-git-send-email-byungchul.park@lge.com>
On Fri, Dec 09, 2016 at 02:12:02PM +0900, Byungchul Park wrote:
> Currently, save_trace() always performs save_stack_trace() for the
> current. However, crossrelease needs to use stack trace data of another
> context instead of the current. So add a parameter for skipping stack
> tracing of the current and make it use trace data, which is already
> saved by crossrelease framework.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
> kernel/locking/lockdep.c | 33 ++++++++++++++++++++-------------
> 1 file changed, 20 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index 3eaa11c..11580ec 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -387,15 +387,22 @@ static void print_lockdep_off(const char *bug_msg)
> #endif
> }
>
> -static int save_trace(struct stack_trace *trace)
> +static int save_trace(struct stack_trace *trace, int skip_tracing)
> {
> - trace->nr_entries = 0;
> - trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
> - trace->entries = stack_trace + nr_stack_trace_entries;
> + unsigned int nr_avail = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
>
> - trace->skip = 3;
> -
> - save_stack_trace(trace);
> + if (skip_tracing) {
> + trace->nr_entries = min(trace->nr_entries, nr_avail);
> + memcpy(stack_trace + nr_stack_trace_entries, trace->entries,
> + trace->nr_entries * sizeof(trace->entries[0]));
> + trace->entries = stack_trace + nr_stack_trace_entries;
> + } else {
> + trace->nr_entries = 0;
> + trace->max_entries = nr_avail;
> + trace->entries = stack_trace + nr_stack_trace_entries;
> + trace->skip = 3;
> + save_stack_trace(trace);
> + }
>
> /*
> * Some daft arches put -1 at the end to indicate its a full trace.
That's pretty nasty semantics.. so when skip_tracing it modifies trace
in-place.
next prev parent reply other threads:[~2017-01-12 16:38 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-09 5:11 [PATCH v4 00/15] lockdep: Implement crossrelease feature Byungchul Park
2016-12-09 5:11 ` [PATCH v4 01/15] x86/dumpstack: Optimize save_stack_trace Byungchul Park
2016-12-09 5:11 ` [PATCH v4 02/15] x86/dumpstack: Add save_stack_trace()_fast() Byungchul Park
2016-12-09 5:11 ` [PATCH v4 03/15] lockdep: Refactor lookup_chain_cache() Byungchul Park
2016-12-09 5:12 ` [PATCH v4 04/15] lockdep: Add a function building a chain between two classes Byungchul Park
2017-01-10 21:00 ` Peter Zijlstra
2017-01-12 1:41 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace Byungchul Park
2017-01-12 16:16 ` Peter Zijlstra
2017-01-13 2:45 ` Byungchul Park
2017-01-13 4:09 ` [PATCH] lockdep: Make a stack_trace instance passed to check_prev_add as an arg Byungchul Park
2017-01-13 4:38 ` Byungchul Park
2017-01-13 10:11 ` [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace Byungchul Park
2017-01-13 10:17 ` [PATCH 1/2] lockdep: Refactor save_trace() Byungchul Park
2017-01-13 10:17 ` [PATCH 2/2] lockdep: Pass a callback arg to check_prev_add() to handle stack_trace Byungchul Park
2017-01-17 15:54 ` [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace Peter Zijlstra
2017-01-18 2:04 ` Byungchul Park
2017-01-18 15:10 ` Peter Zijlstra
2017-01-19 2:47 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 06/15] lockdep: Make save_trace can skip stack tracing of the current Byungchul Park
2017-01-12 16:37 ` Peter Zijlstra [this message]
2017-01-13 0:18 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 07/15] lockdep: Implement crossrelease feature Byungchul Park
2017-01-13 4:39 ` Lai Jiangshan
2017-01-13 5:02 ` Byungchul Park
2017-01-16 15:10 ` Peter Zijlstra
2017-01-17 2:05 ` Byungchul Park
2017-01-17 7:12 ` Peter Zijlstra
2017-01-17 7:49 ` Byungchul Park
2017-01-17 7:14 ` Peter Zijlstra
2017-01-17 7:45 ` Byungchul Park
2017-01-16 15:13 ` Peter Zijlstra
2017-01-17 2:33 ` Byungchul Park
2017-01-17 6:24 ` Boqun Feng
2017-01-17 7:43 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 08/15] lockdep: Make crossrelease use save_stack_trace_fast() Byungchul Park
2016-12-09 5:12 ` [PATCH v4 09/15] lockdep: Make print_circular_bug() crosslock-aware Byungchul Park
2016-12-09 5:12 ` [PATCH v4 10/15] lockdep: Apply crossrelease to completion operation Byungchul Park
2016-12-09 5:12 ` [PATCH v4 11/15] pagemap.h: Remove trailing white space Byungchul Park
2016-12-09 5:12 ` [PATCH v4 12/15] lockdep: Apply crossrelease to PG_locked lock Byungchul Park
2016-12-09 5:12 ` [PATCH v4 13/15] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park
2016-12-09 5:12 ` [PATCH v4 14/15] lockdep: Move data used in CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2016-12-09 5:12 ` [PATCH v4 15/15] lockdep: Crossrelease feature documentation Byungchul Park
2017-01-10 20:08 ` Peter Zijlstra
2017-01-11 1:29 ` Byungchul Park
2017-01-18 6:42 ` Boqun Feng
2017-01-18 10:53 ` Byungchul Park
2017-01-18 11:03 ` Peter Zijlstra
2017-01-18 11:54 ` Byungchul Park
2017-01-18 12:07 ` Peter Zijlstra
2017-01-18 12:14 ` byungchul.park
2017-01-18 14:12 ` Peter Zijlstra
2017-01-19 1:54 ` Byungchul Park
2017-01-18 12:49 ` byungchul.park
2016-12-09 5:21 ` [FYI] Output of 'cat /proc/lockdep' after applying crossrelease Byungchul Park
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