This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] elf: dl-minimal malloc needs to respect fundamental alignment


On 07/11/2016 04:35 AM, Carlos O'Donell wrote:

I agree with H.J. here, this should be MALLOC_ALIGNMENT, and if it's larger
then so be it. It should logically match the behaviour, as best it can, of
glibc's malloc since we're handing off most commonly to that malloc after
relocation. Thus I'd like to see the behaviours harmonized.

Other mallocs may not have the same behaviour but that's not a reason to
avoid MALLOC_ALIGNMENT.

I'm still not convinced. Obviously, we cannot rely on MALLOC_ALIGNMENT anywhere because interposed mallocs may not provide it. So I still don't see the value of compatibility with the main malloc here.

The discussions about fixing libc malloc's alignment are out of scope for
this change IMO. We should focus on fixing ld.so's behaviour.

Out of curiosity have you tried to assemble a unit test for these functions
based on linking directly with dl-minimal.os? It would be nice to run them
through similar testing as is done by malloc.

OK to checkin if you use MALLOC_ALIGMENT.

This change is not exactly trivial because it's currently defined in malloc/malloc.c only. I will need to post another version for review.

Thanks,
Florian


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]