[PATCH] improve performance of std::allocator::deallocate

Jonathan Wakely jwakely@redhat.com
Mon May 20 09:45:00 GMT 2019


On 20/05/19 09:17 +0000, Pádraig Brady wrote:
>
>
>On 04/02/2019 07:33 PM, Padraig Brady wrote:
>> On 03/07/2019 03:43 AM, Jonathan Wakely wrote:
>>> OK, that makes me feel better about it. It's presumably much easier to
>>> upgrade to 5.2 from 5.0 or 5.1 than it would be from 4.x.
>>>
>>>>> How complicated is the fix to prevent the crashes? Would it be
>>>>> feasible for distros to backport that fix? I see that RHEL8 has
>>>>> jemalloc 5.0.1 for example, but if the fix could be backported to that
>>>>> release then it's less of a problem.
>>>> The patch set is simple enough:
>>>> https://github.com/jemalloc/jemalloc/pull/1341/commits
>>> Thanks. That does seem reasonable for distros and other packagers to
>>> backport, if they want to support 5.0 or 5.1 for their users.
>>>
>>> I'm leaning towards accepting the patch for gcc-9 (and if not, we
>>> should do it early in the gcc-10 cycle).
>>>
>> FYI jemalloc 5.2 is released with the fix for zero sized deallocations:
>> https://github.com/jemalloc/jemalloc/releases/tag/5.2.0
>>
>Friendly ping.
>I can create a bug to track if you prefer.

No thanks, patches belong on these lists.

Now that we're in GCC 10 development stage 1 I'm happy to apply the
patch. I think by the time GCC 10 is released it will be reasonable to
expect people to use the fixed version of jemalloc.

I'll do the change today.



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