From: Bjorn Helgaas <helgaas@kernel.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Andi Kleen <ak@linux.intel.com>,
bhelgaas@google.com, x86@kernel.org, linux-pci@vger.kernel.org,
eranian@google.com, Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig
Date: Tue, 14 Mar 2017 21:55:49 -0500 [thread overview]
Message-ID: <20170315025549.GA13191@bhelgaas-glaptop.roam.corp.google.com> (raw)
In-Reply-To: <20170315022414.GC14380@two.firstfloor.org>
On Tue, Mar 14, 2017 at 07:24:14PM -0700, Andi Kleen wrote:
> > I agree that it should be fairly safe to do ECAM/MMCONFIG without
> > locking. Can we handle the decision part by adding a "lockless" bit
> > to struct pci_ops? Old ops don't mention that bit, so it will be
> > initialized to zero and we'll do locking as today. ECAM/MMCONFIG ops
> > can set it and we can skip the locking.
>
> That's what my other patch already did.
Yes, your 1/4 patch does add the "ll_allowed" bit in struct pci_ops.
What I was wondering, but didn't explain very well, was whether
instead of setting that bit at run-time in pci_mmcfg_arch_init(), we
could set it statically in the pci_ops definition, e.g.,
static struct pci_ops ecam_ops = {
.lockless = 1,
.read = ecam_read,
.write = ecam_write,
};
I think it would be easier to read if the lockless-ness were declared
right next to the accessors that need it (or don't need it).
But it is a little confusing with all the different paths, at least on
x86, so maybe it wouldn't be quite that simple.
Bjorn
next prev parent reply other threads:[~2017-03-15 2:55 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 23:21 [PATCH 1/4] pci: Allow lockless access path to PCI mmconfig Andi Kleen
2017-03-02 23:21 ` [PATCH 2/4] pci: Add generic pci_bus_force_mmconfig interface Andi Kleen
2017-03-14 17:34 ` H. Peter Anvin
2017-03-02 23:21 ` [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen
2017-03-14 13:55 ` Thomas Gleixner
2017-03-14 15:41 ` Andi Kleen
2017-03-14 16:40 ` Thomas Gleixner
2017-03-14 17:02 ` Andi Kleen
2017-03-14 17:56 ` Thomas Gleixner
2017-03-14 19:47 ` Bjorn Helgaas
2017-03-15 2:24 ` Andi Kleen
2017-03-15 2:55 ` Bjorn Helgaas [this message]
2017-03-15 10:00 ` Thomas Gleixner
2017-03-15 14:09 ` Bjorn Helgaas
2017-03-16 0:02 ` Andi Kleen
2017-03-16 22:45 ` Thomas Gleixner
2017-03-02 23:21 ` [PATCH 4/4] perf/x86/intel/uncore: Enable forced mmconfig for Intel uncore Andi Kleen
2017-03-14 13:06 ` [PATCH 1/4] pci: Allow lockless access path to PCI mmconfig Thomas Gleixner
2017-03-14 17:28 ` H. Peter Anvin
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