Re: [PATCH V2 2/7] mm/gup: add gup trace points

From	"Shi, Yang" <yang.shi@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH V2 2/7] mm/gup: add gup trace points
Date	2015-12-03 01:20 +0100
Message-ID	<qBpMR-5Y5-13@gated-at.bofh.it> (permalink)
References	<qBoQN-5n9-1@gated-at.bofh.it> <qBoQP-5n9-51@gated-at.bofh.it> <qBpaa-5uf-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 12/2/2015 3:36 PM, Dave Hansen wrote:
> On 12/02/2015 02:53 PM, Yang Shi wrote:
>> diff --git a/mm/gup.c b/mm/gup.c
>> index deafa2c..10245a4 100644
>> --- a/mm/gup.c
>> +++ b/mm/gup.c
>> @@ -13,6 +13,9 @@
>>   #include <linux/rwsem.h>
>>   #include <linux/hugetlb.h>
>>
>> +#define CREATE_TRACE_POINTS
>> +#include <trace/events/gup.h>
>> +
>>   #include <asm/pgtable.h>
>>   #include <asm/tlbflush.h>
>
> This needs to be _the_ last thing that gets #included.  Otherwise, you
> risk colliding with any other trace header that gets implicitly included
> below.

Thanks for the suggestion, will move it to the last.

>
>> @@ -1340,6 +1346,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
>>   					start, len)))
>>   		return 0;
>>
>> +	trace_gup_get_user_pages_fast(start, nr_pages, write, pages);
>> +
>>   	/*
>>   	 * Disable interrupts.  We use the nested form as we can already have
>>   	 * interrupts disabled by get_futex_key.
>
> It would be _really_ nice to be able to see return values from the
> various gup calls as well.  Is that feasible?

I think it should be feasible. kmem_cache_alloc trace event could show 
return value. I'm supposed gup trace events should be able to do the 
same thing.

Regards,
Yang

>

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Thread

[RFC V2] Add gup trace points support Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
  [PATCH V2 5/7] s390: mm/gup: add gup trace points Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
  [PATCH V2 3/7] x86: mm/gup: add gup trace points Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
  [PATCH V2 4/7] mips: mm/gup: add gup trace points Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
  [PATCH V2 2/7] mm/gup: add gup trace points Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
    Re: [PATCH V2 2/7] mm/gup: add gup trace points Dave Hansen <dave.hansen@intel.com> - 2015-12-03 00:40 +0100
      Re: [PATCH V2 2/7] mm/gup: add gup trace points "Shi, Yang" <yang.shi@linaro.org> - 2015-12-03 01:20 +0100
        Re: [PATCH V2 2/7] mm/gup: add gup trace points "Shi, Yang" <yang.shi@linaro.org> - 2015-12-03 02:00 +0100
      Re: [PATCH V2 2/7] mm/gup: add gup trace points Steven Rostedt <rostedt@goodmis.org> - 2015-12-03 05:20 +0100
        Re: [PATCH V2 2/7] mm/gup: add gup trace points "Shi, Yang" <yang.shi@linaro.org> - 2015-12-03 19:40 +0100
          Re: [PATCH V2 2/7] mm/gup: add gup trace points Steven Rostedt <rostedt@goodmis.org> - 2015-12-03 20:10 +0100
            Re: [PATCH V2 2/7] mm/gup: add gup trace points "Shi, Yang" <yang.shi@linaro.org> - 2015-12-03 23:20 +0100
  [PATCH V2 6/7] sh: mm/gup: add gup trace points Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
  [PATCH V2 1/7] trace/events: Add gup trace events Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:20 +0100
    Re: [PATCH V2 1/7] trace/events: Add gup trace events Steven Rostedt <rostedt@goodmis.org> - 2015-12-03 05:10 +0100
      Re: [PATCH V2 1/7] trace/events: Add gup trace events "Shi, Yang" <yang.shi@linaro.org> - 2015-12-03 19:40 +0100
  [PATCH V2 7/7] sparc64: mm/gup: add gup trace points Yang Shi <yang.shi@linaro.org> - 2015-12-03 00:30 +0100

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