On Mon, Apr 11, 2016 at 9:44 AM, Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> wrote:
> On Mon, Mar 14, 2016 at 11:43:43AM +0100, Alexander Potapenko wrote:
>> +depot_stack_handle_t depot_save_stack(struct stack_trace *trace,
>> + gfp_t alloc_flags)
>> +{
>> + u32 hash;
>> + depot_stack_handle_t retval = 0;
>> + struct stack_record *found = NULL, **bucket;
>> + unsigned long flags;
>> + struct page *page = NULL;
>> + void *prealloc = NULL;
>> + bool *rec;
>> +
>> + if (unlikely(trace->nr_entries == 0))
>> + goto fast_exit;
>> +
>> + rec = this_cpu_ptr(&depot_recursion);
>> + /* Don't store the stack if we've been called recursively. */
>> + if (unlikely(*rec))
>> + goto fast_exit;
>> + *rec = true;
>> +
>> + hash = hash_stack(trace->entries, trace->nr_entries);
>> + /* Bad luck, we won't store this stack. */
>> + if (hash == 0)
>> + goto exit;
>
> Hello,
>
> why is hash == 0 skipped?
>
> Thanks.
We have to keep a special value to distinguish allocations for which
we don't have the stack trace for some reason.
Making 0 such a value seems natural.
--
Alexander Potapenko
Software Engineer
Google Germany GmbH
Erika-Mann-Straße, 33
80636 München
Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg
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