Date: Wed, 18 May 2016 11:32:17 -0600 From: Ian Lepore <ian@freebsd.org> To: Nathan Whitehorn <nwhitehorn@freebsd.org>, Justin Hibbits <chmeeedalf@gmail.com>, Scott Long <scottl@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r300154 - head/sys/net Message-ID: <1463592737.1180.294.camel@freebsd.org> In-Reply-To: <759d085c-a485-c2ed-5d70-26eb4d27cdc2@freebsd.org> References: <201605181545.u4IFjCKD030751@repo.freebsd.org> <20160518105033.1eae7432@zhabar.knownspace> <759d085c-a485-c2ed-5d70-26eb4d27cdc2@freebsd.org>
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On Wed, 2016-05-18 at 10:14 -0700, Nathan Whitehorn wrote: > > On 05/18/16 08:50, Justin Hibbits wrote: > > On Wed, 18 May 2016 15:45:12 +0000 (UTC) > > Scott Long <scottl@FreeBSD.org> wrote: > > > > > Author: scottl > > > Date: Wed May 18 15:45:12 2016 > > > New Revision: 300154 > > > URL: https://svnweb.freebsd.org/changeset/base/300154 > > > > > > Log: > > > Activate the NO_64BIT_ATOMICS code for mips and powerpc > > > > > > Modified: > > > head/sys/net/mp_ring.c > > > > > > Modified: head/sys/net/mp_ring.c > > > ================================================================= > > > ============= > > > --- head/sys/net/mp_ring.c Wed May 18 15:44:45 2016 > > > (r300153) +++ head/sys/net/mp_ring.c Wed May 18 15:45:12 > > > 2016 (r300154) @@ -37,15 +37,17 @@ __FBSDID("$FreeBSD$"); > > > #include <sys/malloc.h> > > > #include <machine/cpu.h> > > > > > > - > > > - > > > -#include <net/mp_ring.h> > > > +#if defined(__powerpc__) || defined(__mips__) > > > +#define NO_64BIT_ATOMICS > > > +#endif > > > > > > #if defined(__i386__) > > > #define atomic_cmpset_acq_64 atomic_cmpset_64 > > > #define atomic_cmpset_rel_64 atomic_cmpset_64 > > > #endif > > > > > > +#include <net/mp_ring.h> > > > + > > > union ring_state { > > > struct { > > > uint16_t pidx_head; > > > > > powerpc64 defines both __powerpc__ and __powerpc64__, so you're > > killing > > atomics on powerpc64 with this. > > > > - Justin > > > > Don't all of our 64-bit platforms have 64-bit atomics? So you could > just > #if defined(__LP64__) || defined(__i386__) || > defined(__whatever_the_thing_is_for_mips_n32__) > -Nathan > It may be more complicated than that, though. armv6 can do 64-bit atomics even tho it's 32-bit. armv4, also 32-bit, can do 64-bit atomics in the kernel but not in userland. Maybe machine/atomic.h needs a #define that says whether 64-bit ops are available in the current compilation unit. (And likewise for other bit sizes if we have arches that have other limitations.) -- Ian
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