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Re: Async-signal-safe access to __thread variables from dlopen()ed libraries?
- From: Alexandre Oliva <aoliva at redhat dot com>
- To: Paul Pluzhnikov <ppluzhnikov at google dot com>
- Cc: Ian Lance Taylor <iant at google dot com>, Roland McGrath <roland at hack dot frob dot com>, Richard Henderson <rth at twiddle dot net>, libc-alpha at sourceware dot org, Andrew Hunter <ahh at google dot com>
- Date: Fri, 20 Sep 2013 11:23:55 -0300
- Subject: Re: Async-signal-safe access to __thread variables from dlopen()ed libraries?
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On Sep 18, 2013, Paul Pluzhnikov <ppluzhnikov@google.com> wrote:
> - introduces async-signal-safe mmap-based allocator into elf/dl-misc.c, and
> - updates the rest of the loader to use this allocator when getting space
> for non-static TLS.
Why not make malloc AS-safe instead? I've reviewed it, and having
multiple arenas seems to make it not too hard to use an alternate arena
if the primary arena for a thread happens to be already locked. It's
only if we have to create a new arena that we might get in trouble, but
then, worst case, malloc itself can always fallback to mmapped
allocation.
Wouldn't that be a more advantageous path to take?
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist Red Hat Brazil Compiler Engineer