This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH v2][malloc] Use relaxed atomics for malloc have_fastchunks
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Chris Metcalf <cmetcalf at mellanox dot com>
- Cc: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>, "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, "dj at redhat dot com" <dj at redhat dot com>, nd <nd at arm dot com>
- Date: Wed, 18 Oct 2017 16:51:48 +0000
- Subject: Re: [PATCH v2][malloc] Use relaxed atomics for malloc have_fastchunks
- Authentication-results: sourceware.org; auth=none
- References: <DB6PR0801MB2053F5C639E8EBEE0E90CDB483660@DB6PR0801MB2053.eurprd08.prod.outlook.com> <alpine.DEB.2.20.1710172304020.16511@digraph.polyomino.org.uk> <c8394ede-84bd-2ce2-f489-e40a2d93cecb@mellanox.com>
On Wed, 18 Oct 2017, Chris Metcalf wrote:
> To be fair, we could also synthesize subword atomics for tilepro with compare
> and swap on the surrounding word, so it's not technically impossible to add
> this support. And (as Wilco already demonstrated) it's trivial to fix the
> caller to work around this problem.
I'm pretty sure other architectures in glibc would also require subword
atomics to be synthesized, and some certainly have errors for them at
present - what's unique about tilepro is that the checks trigger on
subword relaxed atomic load/store (whereas more architectures would have
problems with non-relaxed atomics, compre/exchange, etc.).
> However, it's also true that tilepro is no longer an actively-maintained
> platform; the tilegx platform has pretty well supplanted it in practice.
> Perhaps it is time to look at obsoleting tilepro so that its presence in
> the tree doesn't block forward progress for other architectures. I'm
> not aware of any existing tilepro customers that are looking to use
> newer versions of glibc.
Certainly architecture maintainers can propose removal / obsoletion of
their architectures (or subarchitecture variants, etc.), and in the
absence of other people expressing interest in using that architecture I'd
expect such removal / obsoletion proposals to achieve consensus.
--
Joseph S. Myers
joseph@codesourcery.com