From: Peter Zijlstra <peterz@infradead.org>
To: "Reshetova, Elena" <elena.reshetova@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"tj@kernel.org" <tj@kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"lizefan@huawei.com" <lizefan@huawei.com>,
"acme@kernel.org" <acme@kernel.org>,
"alexander.shishkin@linux.intel.com"
<alexander.shishkin@linux.intel.com>,
"eparis@redhat.com" <eparis@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"luto@kernel.org" <luto@kernel.org>,
"keescook@chromium.org" <keescook@chromium.org>,
"dvhart@infradead.org" <dvhart@infradead.org>,
"ebiederm@xmission.com" <ebiederm@xmission.com>
Subject: Re: [PATCH 14/15] futex: convert futex_pi_state.refcount to refcount_t
Date: Fri, 1 Sep 2017 21:12:34 +0200 [thread overview]
Message-ID: <20170901191234.ghybbmpm73miwmkp@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <2236FBA76BA1254E88B949DDB74E612B6FF6369D@IRSMSX102.ger.corp.intel.com>
On Fri, Sep 01, 2017 at 05:03:55PM +0000, Reshetova, Elena wrote:
> > On Fri, Sep 01, 2017 at 01:24:16PM +0000, Reshetova, Elena wrote:
> > >
> > > > On Fri, Sep 01, 2017 at 11:05:33AM +0000, Reshetova, Elena wrote:
> > > > > Actually on the second thought: does the above memory ordering differences
> > > > > really apply when we have ARCH_HAS_REFCOUNT? To me it looks like the way
> > > > > how it is currently implemented for x86 is the same way as it is for atomic
> > cases.
> > > >
> > > > Never look to x86 for memory ordering, its boring.
> > > >
> > > > And yes, for the ARM implementation it can certainly make a difference.
> > >
> > > So, yes, what I am trying to say is that it can really depend if you have
> > ARCH_HAS_REFCOUNT
> > > enabled or not and then also based on architecture. Thus I believe is also true for
> > atomic: there
> > > might be differences when you use arch. dependent version of function or not.
> >
> > So the generic one in lib/refcount.c is already weaker on ARM, they
> > don't need to do a ARCH specific 'fast' implementation for the
> > difference to show up.
>
> But can they make "fast" implementation on ARM that would give stronger memory guarantees?
Whatever for?
next prev parent reply other threads:[~2017-09-01 19:12 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-30 12:22 [PATCH 00/15] v5 kernel core pieces refcount conversions Elena Reshetova
2017-08-30 12:22 ` [PATCH 01/15] sched: convert sighand_struct.count to refcount_t Elena Reshetova
2017-08-30 12:22 ` [PATCH 02/15] sched: convert signal_struct.sigcnt " Elena Reshetova
2017-08-30 12:22 ` [PATCH 03/15] sched: convert user_struct.__count " Elena Reshetova
2017-08-30 12:22 ` [PATCH 04/15] sched: convert numa_group.refcount " Elena Reshetova
2017-08-30 12:22 ` [PATCH 05/15] sched/task_struct: convert task_struct.usage " Elena Reshetova
2017-08-30 12:22 ` [PATCH 06/15] sched/task_struct: convert task_struct.stack_refcount " Elena Reshetova
2017-08-30 12:22 ` [PATCH 07/15] perf: convert perf_event_context.refcount " Elena Reshetova
2017-08-30 12:22 ` [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount " Elena Reshetova
2017-08-30 12:22 ` [PATCH 09/15] perf/ring_buffer: convert ring_buffer.aux_refcount " Elena Reshetova
2017-08-30 12:22 ` [PATCH 10/15] uprobes: convert uprobe.ref " Elena Reshetova
2017-08-30 12:22 ` [PATCH 11/15] nsproxy: convert nsproxy.count " Elena Reshetova
2017-08-30 12:22 ` [PATCH 12/15] groups: convert group_info.usage " Elena Reshetova
2017-08-30 12:22 ` [PATCH 13/15] creds: convert cred.usage " Elena Reshetova
2017-08-30 12:22 ` [PATCH 14/15] futex: convert futex_pi_state.refcount " Elena Reshetova
2017-09-01 7:39 ` Thomas Gleixner
2017-09-01 9:38 ` Peter Zijlstra
2017-09-01 9:43 ` Thomas Gleixner
2017-09-01 10:52 ` Reshetova, Elena
2017-09-01 11:05 ` Reshetova, Elena
2017-09-01 12:34 ` Peter Zijlstra
2017-09-01 13:24 ` Reshetova, Elena
2017-09-01 13:36 ` Peter Zijlstra
2017-09-01 17:03 ` Reshetova, Elena
2017-09-01 19:12 ` Peter Zijlstra [this message]
2017-09-04 10:31 ` Reshetova, Elena
2017-09-04 12:00 ` Peter Zijlstra
2017-09-14 16:02 ` Reshetova, Elena
2017-10-20 12:03 ` Reshetova, Elena
2017-10-20 12:30 ` Thomas Gleixner
2017-10-23 7:36 ` Reshetova, Elena
2017-08-30 12:22 ` [PATCH 15/15] kcov: convert kcov.refcount " Elena Reshetova
2017-08-31 23:48 ` [PATCH 00/15] v5 kernel core pieces refcount conversions Kees Cook
2017-09-01 9:48 ` Peter Zijlstra
2017-09-01 16:55 ` Kees Cook
2017-09-01 17:08 ` Reshetova, Elena
-- strict thread matches above, loose matches on Subject: below --
2017-08-25 9:41 [PATCH 00/15] v4 " Elena Reshetova
2017-08-25 9:41 ` [PATCH 14/15] futex: convert futex_pi_state.refcount to refcount_t Elena Reshetova
2017-07-18 10:29 [PATCH 00/15] v4 kernel core pieces refcount conversions Elena Reshetova
2017-07-18 10:30 ` [PATCH 14/15] futex: convert futex_pi_state.refcount to refcount_t Elena Reshetova
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