From: Peter Zijlstra <peterz@infradead.org>
To: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"Vineet.Gupta1@synopsys.com" <Vineet.Gupta1@synopsys.com>,
"linux-snps-arc@lists.infradead.org"
<linux-snps-arc@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: arc_usr_cmpxchg and preemption
Date: Thu, 15 Mar 2018 12:28:29 +0100 [thread overview]
Message-ID: <20180315112829.GW4064@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1521105128.11552.64.camel@synopsys.com>
On Thu, Mar 15, 2018 at 09:12:09AM +0000, Alexey Brodkin wrote:
> On Thu, 2018-03-15 at 09:18 +0100, Peter Zijlstra wrote:
> > Also, it might make sense to stuff this implementation in some lib/ file
> > somewhere and make all platforms that need it use the same code, afaict
> > there really isn't anything platform specific to it.
>
> Not clear which part do you mean here.
> Are you talking about entire cmpxchg syscall implementation?
Yep.
> Do you think there're many users of that quite an inefficient
> [compared to proper HW version] atomic exchange?
I think there's a bunch of architectures that are in the same boat.
m68k, arm, mips was mentioned. Sure, the moment an arch has hardware
support you don't need the syscall anymore.
I was just thinking it would be good to have a common implementation (if
possible) rather than 4-5 different copies of basically the same thing.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: "Vineet.Gupta1@synopsys.com" <Vineet.Gupta1@synopsys.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"linux-snps-arc@lists.infradead.org"
<linux-snps-arc@lists.infradead.org>
Subject: Re: arc_usr_cmpxchg and preemption
Date: Thu, 15 Mar 2018 12:28:29 +0100 [thread overview]
Message-ID: <20180315112829.GW4064@hirez.programming.kicks-ass.net> (raw)
Message-ID: <20180315112829.DzFk1N9zTSP9D7crqYvMKTrgWUhGw4IZScJhbhoDU6E@z> (raw)
In-Reply-To: <1521105128.11552.64.camel@synopsys.com>
On Thu, Mar 15, 2018 at 09:12:09AM +0000, Alexey Brodkin wrote:
> On Thu, 2018-03-15 at 09:18 +0100, Peter Zijlstra wrote:
> > Also, it might make sense to stuff this implementation in some lib/ file
> > somewhere and make all platforms that need it use the same code, afaict
> > there really isn't anything platform specific to it.
>
> Not clear which part do you mean here.
> Are you talking about entire cmpxchg syscall implementation?
Yep.
> Do you think there're many users of that quite an inefficient
> [compared to proper HW version] atomic exchange?
I think there's a bunch of architectures that are in the same boat.
m68k, arm, mips was mentioned. Sure, the moment an arch has hardware
support you don't need the syscall anymore.
I was just thinking it would be good to have a common implementation (if
possible) rather than 4-5 different copies of basically the same thing.
WARNING: multiple messages have this Message-ID (diff)
From: peterz@infradead.org (Peter Zijlstra)
To: linux-snps-arc@lists.infradead.org
Subject: arc_usr_cmpxchg and preemption
Date: Thu, 15 Mar 2018 12:28:29 +0100 [thread overview]
Message-ID: <20180315112829.GW4064@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1521105128.11552.64.camel@synopsys.com>
On Thu, Mar 15, 2018@09:12:09AM +0000, Alexey Brodkin wrote:
> On Thu, 2018-03-15@09:18 +0100, Peter Zijlstra wrote:
> > Also, it might make sense to stuff this implementation in some lib/ file
> > somewhere and make all platforms that need it use the same code, afaict
> > there really isn't anything platform specific to it.
>
> Not clear which part do you mean here.
> Are you talking about entire cmpxchg syscall implementation?
Yep.
> Do you think there're many users of that quite an inefficient
> [compared to proper HW version] atomic exchange?
I think there's a bunch of architectures that are in the same boat.
m68k, arm, mips was mentioned. Sure, the moment an arch has hardware
support you don't need the syscall anymore.
I was just thinking it would be good to have a common implementation (if
possible) rather than 4-5 different copies of basically the same thing.
next prev parent reply other threads:[~2018-03-15 11:28 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-14 16:36 arc_usr_cmpxchg and preemption Alexey Brodkin
2018-03-14 16:58 ` Vineet Gupta
2018-03-14 16:58 ` Vineet Gupta
2018-03-14 17:53 ` Peter Zijlstra
2018-03-14 17:53 ` Peter Zijlstra
2018-03-14 17:53 ` Peter Zijlstra
2018-03-14 18:20 ` Peter Zijlstra
2018-03-14 18:20 ` Peter Zijlstra
2018-03-14 18:20 ` Peter Zijlstra
2018-03-14 20:38 ` Alexey Brodkin
2018-03-14 20:38 ` Alexey Brodkin
2018-03-14 20:55 ` Vineet Gupta
2018-03-14 20:55 ` Vineet Gupta
2018-03-15 8:18 ` Peter Zijlstra
2018-03-15 8:18 ` Peter Zijlstra
2018-03-15 8:18 ` Peter Zijlstra
2018-03-15 9:12 ` Alexey Brodkin
2018-03-15 9:12 ` Alexey Brodkin
2018-03-15 11:28 ` Peter Zijlstra [this message]
2018-03-15 11:28 ` Peter Zijlstra
2018-03-15 11:28 ` Peter Zijlstra
2018-03-15 19:03 ` Alexey Brodkin
2018-03-15 19:03 ` Alexey Brodkin
2018-03-15 19:03 ` Alexey Brodkin
2018-03-16 7:55 ` Peter Zijlstra
2018-03-16 7:55 ` Peter Zijlstra
2018-03-16 7:55 ` Peter Zijlstra
2018-03-16 18:12 ` Max Filippov
2018-03-16 18:12 ` Max Filippov
2018-03-16 17:33 ` Alexey Brodkin
2018-03-16 17:33 ` Alexey Brodkin
2018-03-16 17:54 ` Vineet Gupta
2018-03-16 17:54 ` Vineet Gupta
2018-03-16 17:58 ` Peter Zijlstra
2018-03-16 17:58 ` Peter Zijlstra
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