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From: Alexei Starovoitov <ast@plumgrid.com>
To: "Wangnan (F)" <wangnan0@huawei.com>,
	Kaixu Xia <xiakaixu@huawei.com>,
	davem@davemloft.net, acme@kernel.org, mingo@redhat.com,
	a.p.zijlstra@chello.nl, masami.hiramatsu.pt@hitachi.com,
	jolsa@kernel.org
Cc: linux-kernel@vger.kernel.org, pi3orama@163.com, hekuang@huawei.com
Subject: Re: [PATCH v2 1/5] bpf: Add new bpf map type to store the pointer to struct perf_event
Date: Wed, 22 Jul 2015 18:39:12 -0700	[thread overview]
Message-ID: <55B045C0.3080606@plumgrid.com> (raw)
In-Reply-To: <55B03E99.7000803@huawei.com>

On 7/22/15 6:08 PM, Wangnan (F) wrote:
> Then we should find another way to prevent user create a large map but
> only use
> a small portion of it, since normal array map can't report whether a
> slot is used
> or not. When releasing the map, we have to release each perf event.
> Currently the only
> way is to check map value in each slot.

yeah. In prog_array each element is either NULL ptr or valid
'struct bpf_prog *'. Why not to do the same for perf_event_array?


  reply	other threads:[~2015-07-23  1:39 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-22  8:09 [PATCH v2 0/5] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Kaixu Xia
2015-07-22  8:09 ` [PATCH v2 1/5] bpf: Add new bpf map type to store the pointer to struct perf_event Kaixu Xia
2015-07-23  0:48   ` Alexei Starovoitov
2015-07-23  1:08     ` Wangnan (F)
2015-07-23  1:39       ` Alexei Starovoitov [this message]
2015-07-22  8:09 ` [PATCH v2 2/5] bpf: Add function map->ops->map_traverse_elem() to traverse map elems Kaixu Xia
2015-07-23  1:00   ` Alexei Starovoitov
2015-07-22  8:09 ` [PATCH v2 3/5] bpf: Save the pointer to struct perf_event to map Kaixu Xia
2015-07-23  1:08   ` Alexei Starovoitov
2015-07-22  8:09 ` [PATCH v2 4/5] bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter Kaixu Xia
2015-07-23  1:14   ` Alexei Starovoitov
2015-07-23  2:12     ` xiakaixu
2015-07-23  2:22       ` Alexei Starovoitov
2015-07-23  2:39         ` xiakaixu
2015-07-22  8:09 ` [PATCH v2 5/5] samples/bpf: example of get selected PMU counter value Kaixu Xia
2015-07-23  1:16   ` Alexei Starovoitov
2015-07-23 23:33 ` [PATCH v2 0/5] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Daniel Borkmann
2015-07-25  2:14   ` xiakaixu

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