From: Atish Patra <Atish.Patra@wdc.com>
To: "hch@lst.de" <hch@lst.de>
Cc: "linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"palmer@sifive.com" <palmer@sifive.com>,
"paul.walmsley@sifive.com" <paul.walmsley@sifive.com>
Subject: Re: [PATCH 3/6] riscv: optimize send_ipi_single
Date: Tue, 27 Aug 2019 18:48:19 +0000 [thread overview]
Message-ID: <787bcfefcbd5eacc04dd6681ccbfc034a7e6507d.camel@wdc.com> (raw)
In-Reply-To: <20190826112937.GB15002@lst.de>
On Mon, 2019-08-26 at 13:29 +0200, hch@lst.de wrote:
> On Sat, Aug 24, 2019 at 12:26:26AM +0000, Atish Patra wrote:
> > > static void send_ipi_single(int cpu, enum ipi_message_type op)
> > > {
> > > - send_ipi_mask(cpumask_of(cpu), op);
> > > + int hartid = cpuid_to_hartid_map(cpu);
> > > +
> > > + smp_mb__before_atomic();
> > > + set_bit(op, &ipi_data[cpu].bits);
> > > + smp_mb__after_atomic();
> > > +
> > > + sbi_send_ipi(cpumask_bits(cpumask_of(hartid)));
> >
> > The only cost save I see is you don't have to cpumask_clear
> > anymore.
> > Is there any other cost save ? If not is it worth duplicating the
> > code
> > ?
> >
> > May be I am being too pedantic here.. :) :)
>
> It avoids the additional potentially huge cpumask, and generally
> makes
> the code a lot more obvious. This might not really be needed, but
> helps with sharing the code nicely with the native IPI path.
ok.
Reviewed-by: Atish Patra <atish.patra@wdc.com>
--
Regards,
Atish
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next prev parent reply other threads:[~2019-08-27 18:48 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 14:58 misc riscv cleanups Christoph Hellwig
2019-08-21 14:58 ` [PATCH 1/6] riscv: refactor the IPI code Christoph Hellwig
2019-08-24 1:03 ` Atish Patra
2019-09-05 8:44 ` Paul Walmsley
2019-08-21 14:58 ` [PATCH 2/6] riscv: cleanup send_ipi_mask Christoph Hellwig
2019-08-24 0:11 ` Atish Patra
2019-08-26 11:28 ` hch
2019-08-27 18:45 ` Atish Patra
2019-09-05 8:46 ` Paul Walmsley
2019-08-21 14:58 ` [PATCH 3/6] riscv: optimize send_ipi_single Christoph Hellwig
2019-08-24 0:26 ` Atish Patra
2019-08-26 11:29 ` hch
2019-08-27 18:48 ` Atish Patra [this message]
2019-09-05 8:48 ` Paul Walmsley
2019-08-21 14:58 ` [PATCH 4/6] riscv: cleanup riscv_cpuid_to_hartid_mask Christoph Hellwig
2019-08-24 0:03 ` Atish Patra
2019-09-05 8:50 ` Paul Walmsley
2019-08-21 14:58 ` [PATCH 5/6] riscv: don't use the rdtime(h) pseudo-instructions Christoph Hellwig
2019-08-24 0:37 ` Atish Patra
2019-08-24 0:43 ` Atish Patra
2019-08-26 11:30 ` hch
2019-08-27 18:50 ` Atish Patra
2019-09-05 8:55 ` Paul Walmsley
2019-08-21 14:58 ` [PATCH 6/6] riscv: move the TLB flush logic out of line Christoph Hellwig
2019-08-24 0:03 ` Atish Patra
2019-09-05 8:58 ` Paul Walmsley
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