Live allocation iterator

[SNL]

This looks relevant but never was pushed upstream.

https://www.mail-archive.com/jemalloc-discuss@canonware.com/msg00027.html


Any thoughts on this patch set keeping in mind jemalloc-dev current state ?
Any design/architectural inputs are also appreciated. This seems to have
worked well for Alessandro who shared the patchset, I dont see these
changes in their current code base though.

On Wed, Mar 25, 2015 at 11:25 AM, SNL <snl20465 at gmail.com> wrote:

> Does your use case allow you to wrap the allocator and keep a side table
> which supports iteration, or can you trace allocation activity and
> post-process it?
>
> => This is what I have implemented currently but this does not scale for
> multithreaded programs due to locking issues. I was pondering over idea of
> not doing any book keeping myself and use jemalloc data structures ( and
> efficient low level locking ) for my purpose.
>
> Is this not possible even when all my metadata objects ( which hold user
> allocation base and extent ) are fixed sized and allocated from a separate
> arena ? I was under the impression that I should be able to mask and find
> out offsets within chunk->region->pages and find out objects. As my objects
> are all fixed size, they would be contiguous in memory. Is this valid
> understanding ?
>
>
> On Tue, Mar 24, 2015 at 11:16 PM, Jason Evans <jasone at canonware.com>
> wrote:
>
>> On Mar 24, 2015, at 6:53 AM, SNL <snl20465 at gmail.com> wrote:
>>
>> If this is not possible ( I see an old post which says jemalloc does not
>> have this infra but that was back in 2012 ). Is it possible to iterate over
>> just an arena and dump all allocations in it  ? Basically, I have memory
>> pool implemented on top of jemalloc which holds metadata about all other
>> allocations jemalloc does, if I can iterate over this arena and get hold of
>> metadata, I can get hold of each allocation as well.
>>
>> Any thoughts would be appreciated.
>>
>> On Tue, Mar 24, 2015 at 5:28 PM, SNL <snl20465 at gmail.com> wrote:
>>
>>>
>>> My use case is to walk through all live allocations ( the ones which are
>>> not freed yet) of all sizes the program ever made and dump it as the end of
>>> the program or on demand. I have looked at stats but I want something with
>>> even more details. Basically, the function should be able to iterate
>>> through all arenas and print details on following lines:
>>>
>>> arena = 1 base = 0x7fd7beb88800 size = 15 bytes etc
>>>
>>> Is there any api in jemalloc which already does subset of this  ? Any
>>> pointers will be helpful.
>>>
>>
>> jemalloc doesn't support iteration over live allocations, and it's
>> unlikely to ever directly support iteration, because the feature imposes
>> nontrivial additional complexity for limited benefit.  The closest thing
>> under consideration is https://github.com/jemalloc/jemalloc/issues/203,
>> but I don't plan to work on that until at least next year.
>>
>> Does your use case allow you to wrap the allocator and keep a side table
>> which supports iteration, or can you trace allocation activity and
>> post-process it?
>>
>> Jason
>>
>
>
>
> --
>
> Cheers,
> Sunny.
>



-- 

Cheers,
Sunny.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://jemalloc.net/mailman/jemalloc-discuss/attachments/20150325/95492d09/attachment.html>