inlining AllocateHeap()

[Thomas Stüfe]

Hi Yasumasa, David,

Maybe it would make sense to make the number-of-frames-to-skip-parameter
configurable?

Because the direct caller of AllocateHeap or os::malloc may also not be
interesting but still a generic wrapper. So, the user doing the allocation
trace could finetune this parameter to fit his needs.

Thomas



On Fri, Mar 13, 2015 at 6:40 AM, David Holmes <david.holmes at oracle.com>
wrote:

> Hi Yasumasa,
>
> On 12/03/2015 9:58 PM, Yasumasa Suenaga wrote:
>
>> Hi all,
>>
>> I tried to use NMT with details option on OpenJDK7 on RHEL6.6, but I got
>> address at AllocateHeap() as malloc() caller.
>>
>> I checked symbol in libjvm.so <http://libjvm.so/> in OracleJDK8u40 Linux
>> x64, it has AllocateHeap()
>> symbol.
>>
>> AllocateHeap() is defined as inline function, and it gives CURRENT_PC to
>> os::malloc(). I guess that implementation expects AllocateHeap() will be
>> inlined.
>>
>
> It seems so.
>
>  It may occur with GCC (g++) optimization only, however I want to fix it to
>> analyze native memory with NMT on Linux.
>>
>
> According to the docs [1]:
>
> "GCC does not inline any functions when not optimizing unless you specify
> the ‘always_inline’ attribute for the function"
>
>  I applied patch as below. This patch makes AllocateHeap() as inline
>> function.
>> --------------
>> diff -r af3b0db91659 src/share/vm/memory/allocation.inline.hpp
>> --- a/src/share/vm/memory/allocation.inline.hpp Mon Mar 09 09:30:16 2015
>> -0700
>> +++ b/src/share/vm/memory/allocation.inline.hpp Thu Mar 12 20:45:57 2015
>> +0900
>> @@ -62,11 +62,18 @@
>>     }
>>     return p;
>> }
>> +
>> +#ifdef __GNUC__
>> +__attribute__((always_inline))
>> +#endif
>>
>
> I dislike seeing the gcc specific directives in common code. I'm wondering
> whether we should perhaps only use CURRENT_PC in product (and optimized?)
> builds and use CALLER_PC otherwise. That would be imperfect of course It
> also makes me wonder whether the inlining is occurring as expected on other
> platforms.
>
> I'd like to get other people's views on this.
>
> Thanks,
> David
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Inline.html
>
>
>  inline char* AllocateHeap(size_t size, MEMFLAGS flags,
>>       AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
>>     return AllocateHeap(size, flags, CURRENT_PC, alloc_failmode);
>> }
>>
>> +#ifdef __GNUC__
>> +__attribute__((always_inline))
>> +#endif
>> inline char* ReallocateHeap(char *old, size_t size, MEMFLAGS flag,
>>       AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
>>     char* p = (char*) os::realloc(old, size, flag, CURRENT_PC);
>> --------------
>>
>> If this patch is accepted, I will file it to JBS and will upload webrev.
>>
>> Thanks,
>>
>> Yasumasa
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/serviceability-dev/attachments/20150313/5bdcbe2a/attachment.html>