From: Nicholas Piggin <npiggin@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>,
Arnd Bergmann <arnd@arndb.de>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Rich Felker <dalias@libc.org>,
David Howells <dhowells@redhat.com>,
Daniel Lustig <dlustig@nvidia.com>,
linux-arch <linux-arch@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
"Maciej W. Rozycki" <macro@linux-mips.org>,
Ingo Molnar <mingo@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Palmer Dabbelt <palmer@sifive.com>,
Paul Burton <paul.burton@mips.com>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Alan Stern <stern@rowland.harvard.edu>,
Tony Luck <tony.luck@intel.com>,
Will Deacon <will.deacon@arm.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>
Subject: Re: [PATCH 01/20] asm-generic/mmiowb: Add generic implementation of mmiowb() tracking
Date: Sun, 03 Mar 2019 20:05:23 +1000 [thread overview]
Message-ID: <1551606848.8cceyn7nhv.astroid@bobo.none> (raw)
In-Reply-To: <CAHk-=whVN58nWh29jvXx+X-Yx9dCC6BeAZOtKak+d01y_UVg=A@mail.gmail.com>
Linus Torvalds's on March 3, 2019 2:29 pm:
> On Sat, Mar 2, 2019, 19:34 Nicholas Piggin <npiggin@gmail.com> wrote:
>
>>
>> It doesn't have to be done all at once with this series, obviously this
>> is a big improvement on its own. But why perpetuate the nomenclature
>> and concept for new code added now?
>>
>
> What nomenclature?
>
> Nobody will be using mmiowb(). That's the whole point of the patch series.
>
> It's now an entirely internal name, and nobody cares.
Why even bother with it at all, "internal" or not? Just get rid of
mmiowb, the concept is obsolete.
> And none of this has anything to do with wmb(), since it's about IO being
> ordered across cpu's by spin locks, not by barriers.
>
> So I'm not seeing what you're arguing about.
Pretend ia64 doesn't exist for a minute. Now the regular mb/wmb barriers
orders IO across CPUs with respect to their cacheable accesses.
Regardless of whether that cacheable access is a spin lock, a bit lock,
an atomic, a mutex... This is how it was before mmiowb came along.
Nothing wrong with this series to make spinlocks order mmio, but why
call it mmiowb? Another patch could rename ia64's mmiowb and then the
name can be removed from the tree completely.
Thanks,
Nick
next prev parent reply other threads:[~2019-03-03 10:05 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-01 14:03 [PATCH 00/20] Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb()) Will Deacon
2019-03-01 14:03 ` [PATCH 01/20] asm-generic/mmiowb: Add generic implementation of mmiowb() tracking Will Deacon
2019-03-03 1:43 ` Nicholas Piggin
2019-03-03 2:18 ` Linus Torvalds
2019-03-03 3:34 ` Nicholas Piggin
[not found] ` <CAHk-=whVN58nWh29jvXx+X-Yx9dCC6BeAZOtKak+d01y_UVg=A@mail.gmail.com>
2019-03-03 10:05 ` Nicholas Piggin [this message]
2019-03-03 18:48 ` Linus Torvalds
2019-03-05 0:21 ` Nicholas Piggin
2019-03-05 0:33 ` Linus Torvalds
2019-03-03 9:26 ` Michael Ellerman
2019-03-03 10:07 ` Nicholas Piggin
2019-03-04 1:01 ` Michael Ellerman
2019-03-05 0:21 ` Nicholas Piggin
2019-03-04 10:24 ` Michael Ellerman
2019-03-05 0:19 ` Linus Torvalds
2019-03-07 0:47 ` Michael Ellerman
2019-03-07 1:13 ` Linus Torvalds
2019-03-07 9:13 ` Peter Zijlstra
2019-03-01 14:03 ` [PATCH 02/20] arch: Use asm-generic header for asm/mmiowb.h Will Deacon
2019-03-01 14:03 ` [PATCH 03/20] mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors Will Deacon
2019-03-03 1:47 ` Nicholas Piggin
2019-03-01 14:03 ` [PATCH 04/20] ARM/io: Remove useless definition of mmiowb() Will Deacon
2019-03-01 14:03 ` [PATCH 05/20] arm64/io: " Will Deacon
2019-03-01 14:03 ` [PATCH 06/20] x86/io: " Will Deacon
2019-03-01 14:03 ` [PATCH 07/20] nds32/io: " Will Deacon
2019-03-01 14:03 ` [PATCH 08/20] m68k/io: " Will Deacon
2019-03-01 14:03 ` [PATCH 09/20] sh/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() Will Deacon
2019-03-01 14:03 ` [PATCH 10/20] mips/mmiowb: " Will Deacon
2019-03-01 22:16 ` Paul Burton
2019-03-01 14:03 ` [PATCH 11/20] ia64/mmiowb: " Will Deacon
2019-03-01 14:03 ` [PATCH 12/20] powerpc/mmiowb: Hook up mmwiob() implementation to asm-generic code Will Deacon
2019-03-02 12:46 ` Michael Ellerman
2019-03-01 14:03 ` [PATCH 13/20] riscv/mmiowb: " Will Deacon
2019-03-01 21:13 ` Palmer Dabbelt
2019-03-01 14:03 ` [PATCH 14/20] Documentation: Kill all references to mmiowb() Will Deacon
2019-03-01 14:03 ` [PATCH 15/20] drivers: Remove useless trailing comments from mmiowb() invocations Will Deacon
2019-03-01 14:03 ` [PATCH 16/20] drivers: Remove explicit invocations of mmiowb() Will Deacon
2019-03-01 14:03 ` [PATCH 17/20] scsi/qla1280: Remove stale comment about mmiowb() Will Deacon
2019-03-01 14:03 ` [PATCH 18/20] i40iw: Redefine i40iw_mmiowb() to do nothing Will Deacon
2019-03-01 14:03 ` [PATCH 19/20] net/ethernet/silan/sc92031: Remove stale comment about mmiowb() Will Deacon
2019-03-01 14:03 ` [PATCH 20/20] arch: Remove dummy mmiowb() definitions from arch code Will Deacon
2019-03-01 16:41 ` [PATCH 00/20] Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb()) Linus Torvalds
2019-03-02 12:56 ` Michael Ellerman
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