Messages in this thread Patch in this message | | | Subject | Re: [PATCH] kmemleak: Fix scheduling-while-atomic bug | From | Catalin Marinas <> | Date | Thu, 02 Jul 2009 10:48:28 +0100 |
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On Wed, 2009-07-01 at 11:30 +0200, Ingo Molnar wrote: > * Catalin Marinas <catalin.marinas@arm.com> wrote: > > > > The minimal fix below removes scan_yield() and adds a > > > cond_resched() to the outmost (safe) place of the scanning > > > thread. This solves the regression. > > > > With CONFIG_PREEMPT disabled it won't reschedule during the bss > > scanning but I don't see this as a real issue (task stacks > > scanning probably takes longer anyway). > > Yeah. I suspect one more cond_resched() could be added - i just > didnt see an obvious place for it, given that scan_block() is being > called with asymetric held-locks contexts.
Now that your patch was merged, I propose adding a few more cond_resched() calls, useful for the !PREEMPT case:
kmemleak: Add more cond_resched() calls in the scanning thread
From: Catalin Marinas <catalin.marinas@arm.com>
Following recent patch to no longer reschedule in the scan_block() function, we need a few more cond_resched() calls in the kmemleak_scan() function (useful if PREEMPT is disabled).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- mm/kmemleak.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 013f188..b4f675e 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -932,13 +932,16 @@ static void kmemleak_scan(void) /* data/bss scanning */ scan_block(_sdata, _edata, NULL); + cond_resched(); scan_block(__bss_start, __bss_stop, NULL); #ifdef CONFIG_SMP /* per-cpu sections scanning */ - for_each_possible_cpu(i) + for_each_possible_cpu(i) { + cond_resched(); scan_block(__per_cpu_start + per_cpu_offset(i), __per_cpu_end + per_cpu_offset(i), NULL); + } #endif /* @@ -960,6 +963,7 @@ static void kmemleak_scan(void) /* only scan if page is in use */ if (page_count(page) == 0) continue; + cond_resched(); scan_block(page, page + 1, NULL); } } @@ -969,6 +973,7 @@ static void kmemleak_scan(void) * not enabled by default. */ if (kmemleak_stack_scan) { + cond_resched(); read_lock(&tasklist_lock); for_each_process(task) scan_block(task_stack_page(task),
-- Catalin
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