From: Alexei Starovoitov <ast@plumgrid.com>
To: Peter Zijlstra <peterz@infradead.org>, Kaixu Xia <xiakaixu@huawei.com>
Cc: davem@davemloft.net, acme@kernel.org, mingo@redhat.com,
masami.hiramatsu.pt@hitachi.com, jolsa@kernel.org,
daniel@iogearbox.net, wangnan0@huawei.com,
linux-kernel@vger.kernel.org, pi3orama@163.com,
hekuang@huawei.com, netdev@vger.kernel.org
Subject: Re: [PATCH v6 3/4] bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter
Date: Wed, 5 Aug 2015 09:00:43 -0700 [thread overview]
Message-ID: <55C2332B.3010708@plumgrid.com> (raw)
In-Reply-To: <20150805101506.GY18673@twins.programming.kicks-ass.net>
On 8/5/15 3:15 AM, Peter Zijlstra wrote:
> On Wed, Aug 05, 2015 at 12:04:25PM +0200, Peter Zijlstra wrote:
>> On Tue, Aug 04, 2015 at 08:58:15AM +0000, Kaixu Xia wrote:
>
>>> + event->ctx->task != current)
>
> Strictly speaking we should hold rcu_read_lock around dereferencing
> event->ctx (or have IRQs disabled -- although I know Paul doesn't like
> us relying on that).
programs are always executing under rcu_read_lock, so we should be good
here too.
next prev parent reply other threads:[~2015-08-05 16:00 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-04 8:58 [PATCH v6 0/4] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Kaixu Xia
2015-08-04 8:58 ` [PATCH v6 1/4] bpf: Make the bpf_prog_array_map more generic Kaixu Xia
2015-08-04 8:58 ` [PATCH v6 2/4] bpf: Add new bpf map type to store the pointer to struct perf_event Kaixu Xia
2015-08-04 17:43 ` Alexei Starovoitov
2015-08-05 9:41 ` Peter Zijlstra
2015-08-05 9:39 ` Peter Zijlstra
2015-08-05 9:43 ` Peter Zijlstra
2015-08-04 8:58 ` [PATCH v6 3/4] bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter Kaixu Xia
2015-08-04 17:55 ` Alexei Starovoitov
2015-08-05 2:09 ` xiakaixu
2015-08-05 10:04 ` Peter Zijlstra
2015-08-05 10:15 ` Peter Zijlstra
2015-08-05 16:00 ` Alexei Starovoitov [this message]
2015-08-05 10:31 ` xiakaixu
2015-08-05 13:53 ` Peter Zijlstra
2015-08-05 13:59 ` Peter Zijlstra
2015-08-05 16:08 ` Alexei Starovoitov
2015-08-05 16:21 ` Peter Zijlstra
2015-08-06 2:49 ` xiakaixu
2015-08-05 15:59 ` Alexei Starovoitov
2015-08-04 8:58 ` [PATCH v6 4/4] samples/bpf: example of get selected PMU counter value Kaixu Xia
2015-08-05 10:06 ` [PATCH v6 0/4] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Peter Zijlstra
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