From: Andrew Morton <akpm@osdl.org>
To: Stephane Eranian <eranian@frankl.hpl.hp.com>
Cc: linux-kernel@vger.kernel.org, eranian@hpl.hp.com
Subject: Re: [PATCH 7/18] 2.6.17.9 perfmon2 patch for review: PMU interruption support
Date: Wed, 23 Aug 2006 15:40:57 -0700 [thread overview]
Message-ID: <20060823154057.4d6d444b.akpm@osdl.org> (raw)
In-Reply-To: <200608230805.k7N85wQc000420@frankl.hpl.hp.com>
On Wed, 23 Aug 2006 01:05:58 -0700
Stephane Eranian <eranian@frankl.hpl.hp.com> wrote:
> ...
>
> +irqreturn_t pfm_interrupt_handler(int irq, void *arg, struct pt_regs *regs)
> +{
> + u64 start_cycles, total_cycles;
> +
> + get_cpu();
> +
> + start_cycles = pfm_arch_get_itc();
> +
> + __pfm_interrupt_handler(regs);
> +
> + total_cycles = pfm_arch_get_itc();
> +
> + __get_cpu_var(pfm_stats).pfm_ovfl_intr_cycles += total_cycles - start_cycles;
> +
> + put_cpu_no_resched();
> + return IRQ_HANDLED;
> +}
If this code is only ever called from interrupt context then I suspect the
get_cpu() is not needed. __get_cpu_var() requires that preemption be
disabled (so we cannot wander over to a different CPU midway) but IRQ
code doesn't get preempted.
next prev parent reply other threads:[~2006-08-23 22:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-23 8:05 Stephane Eranian
2006-08-23 22:40 ` Andrew Morton [this message]
2006-08-28 15:24 ` Stephane Eranian
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