Hi, Would not globally overwriting malloc/free with the custom implementation achieve the desired behavior (instead of providing hooks for installing malloc overrides in each and every library)?
Max On Mon, Nov 28, 2016 at 5:08 AM, Auer, Jens <[email protected]> wrote: > Hi, > > I don't see a big problem with the C API except that C doesn't support > overloads. So if the function has a new name, e.g. > zmq_ctx_new_with_allocator, everything stays plain C. The default instance > would be a > > static void* malloc_(size_t n, void*) {return malloc(n);} > static void free_(void* ptr, size_t n, void*) {free(ptr);} > > allocator_t alloc{ > NULL, > malloc_, > free_ > }; > > context_t then stores the member and gets methods to forward memory > allocations to the function pointers, passing the hint pointer as an > additional argument. > > In my C++ code, I can then use an allocator > static void* allocate(size_t n, void* obj) {return > static_cast<std::allocator<char>>(obj)->allocate(n); } > static void free_(void* ptr, size_t n, void*obj) { > static_cast<std::allocator<char>>(obj)->deallocate(ptr, n); } > > std::allocator<char> a; > allocator_t zmqAlloc{ > &a, > allocate, > free_ > }; > > void* ctx = zmq_ctx_new_with_allocator(&zmqAlloc); > > I think this should work? > > Best wishes, > Jens > > -- > Dr. Jens Auer | CGI | Software Engineer > CGI Deutschland Ltd. & Co. KG > Rheinstraße 95 | 64295 Darmstadt | Germany > T: +49 6151 36860 154 > [email protected] > Unsere Pflichtangaben gemäß § 35a GmbHG / §§ 161, 125a HGB finden Sie > unter de.cgi.com/pflichtangaben. > > CONFIDENTIALITY NOTICE: Proprietary/Confidential information belonging to > CGI Group Inc. and its affiliates may be contained in this message. If you > are not a recipient indicated or intended in this message (or responsible > for delivery of this message to such person), or you think for any reason > that this message may have been addressed to you in error, you may not use > or copy or deliver this message to anyone else. In such case, you should > destroy this message and are asked to notify the sender by reply e-mail. > > > > -----Original Message----- > > From: zeromq-dev [mailto:[email protected]] On Behalf > Of > > Luca Boccassi > > Sent: 28 November 2016 12:30 > > To: ZeroMQ development list > > Subject: Re: [zeromq-dev] On hooking memory allocations > > > > That would work for an internal API, but given we expose a C API > unfortunately I > > don't think that would work as a public API :-( And I think for this use > case they > > would require a public API. > > > > As an external API, a new zmq_ctx_set that takes a callback would have > been ideal, > > but it only takes int. So perhaps a new zmq_ctx_set_allocator that takes > a callback > > pointer would be the next best. > > > > An alternative would be to have a system similar to what we use for the > poll > > implementation (epoll kqueue select etc), but this would be a build-time > option, > > and the implementation would have to be checked in, which I don't think > is an > > option for this case, right? > > > > On Mon, 2016-11-28 at 10:51 +0000, Auer, Jens wrote: > > > Hi, > > > > > > I am just a user, but I would love to see this change. I have thinking > > > about this and I would like to be able to pass a C++ allocator object > > > to ZeroMQ, so a simple function hook is not enough. My idea is to > > > define a struct in the interface > > > > > > struct allocator_t > > > { > > > void* hint; > > > void* (allocate)(size_t, void*); > > > void (deallocate)(void*, size_t, void*); }; > > > > > > and store this in the context object. Since I don't think that this > should be > > changed during runtime, I would create a new zmq_ctx_new overload which > takes a > > parameter of type allocator_t. The default value would be to call > malloc/free. > > > > > > Cheers, > > > Jens > > > > > > -- > > > Jens Auer | CGI | Software-Engineer > > > CGI (Germany) GmbH & Co. KG > > > Rheinstraße 95 | 64295 Darmstadt | Germany > > > T: +49 6151 36860 154 > > > [email protected]<mailto:[email protected]> > > > Unsere Pflichtangaben gemäß § 35a GmbHG / §§ 161, 125a HGB finden Sie > unter > > de.cgi.com/pflichtangaben<http://de.cgi.com/pflichtangaben>. > > > > > > CONFIDENTIALITY NOTICE: Proprietary/Confidential information belonging > to CGI > > Group Inc. and its affiliates may be contained in this message. If you > are not a > > recipient indicated or intended in this message (or responsible for > delivery of this > > message to such person), or you think for any reason that this message > may have > > been addressed to you in error, you may not use or copy or deliver this > message to > > anyone else. In such case, you should destroy this message and are asked > to notify > > the sender by reply e-mail. > > > ________________________________ > > > Von: zeromq-dev [[email protected]]" im Auftrag von > > > "Petteri Salo [[email protected]] > > > Gesendet: Montag, 28. November 2016 09:40 > > > An: [email protected] > > > Betreff: [zeromq-dev] On hooking memory allocations > > > > > > Hello, > > > > > > Let me first do a little introduction as I'm new to this list. I'm a > software engineer > > with 15+ years of experience working on games at a company called Remedy > > Entertainment Ltd. We've done games for PC, and various games consoles > over the > > years. Most recently we did Quantum Break for Xbox One. > > > > > > I've now been tasked with evaluating ZeroMQ. One important feature of > any > > library we use in games is the ability to hook all memory allocations - > this is to allow > > the use of custom memory allocators and/or for tracking when and where > memory is > > allocated. > > > > > > I've searched the libzmq source code and there is about 150 uses of > new, malloc, > > realloc , etc. > > > > > > If we were to adopt libzmq we'd like to put in allocation hooks and > that work > > would then be something that we'd like to contribute back to the > project. Having > > those hooks in the main repository would then make it easier for us to > adopt future > > changes to the library. > > > > > > So, my question is would this kind of change be something that would be > > accepted? Of course assuming that coding conventions, proper way of > submitting > > the patch etc. are followed. I do realize that one would want to see the > actual code > > before accepting. I'm interested in the principle of accepting a change > such as this, > > since it would introduce a new "rule" for working ión libzmq source code > : "All > > allocations shall go through an allocation hook." > > > > > > Best Regards, > > > > > > Petteri Salo > > > > > > > > > _______________________________________________ > > > zeromq-dev mailing list > > > [email protected] > > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > _______________________________________________ > zeromq-dev mailing list > [email protected] > http://lists.zeromq.org/mailman/listinfo/zeromq-dev >
_______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
