From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Ming Lei <tom.leiming@gmail.com>
Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH 6/9] bpf: arraymap: introduce BPF_MAP_TYPE_ARRAY_PERCPU
Date: Mon, 11 Jan 2016 11:14:34 -0800 [thread overview]
Message-ID: <20160111191433.GC26495@ast-mbp.thefacebook.com> (raw)
In-Reply-To: <1452527821-12276-7-git-send-email-tom.leiming@gmail.com>
On Mon, Jan 11, 2016 at 11:56:58PM +0800, Ming Lei wrote:
> This patch introduces percpu array map so that expensive
> atomic operations can be avoided in eBPF prog in case of
> ARRAY map.
>
> PERCPU MAP uses the percpu version of update/lookup element
> helpers and callbacks to access element in the map, and
> the previous update/lookup element helpers and callbacks
> don't work at the same time.
>
> Signed-off-by: Ming Lei <tom.leiming@gmail.com>
useful stuff!
> + if (percpu) {
> + if (alloc_percpu_array(array, attr->max_entries,
> + attr->value_size)) {
> + kvfree(array);
> + return ERR_PTR(-ENOMEM);
> + }
> + array->map.pages = round_up(attr->max_entries *
> + attr->value_size * num_possible_cpus(),
> + PAGE_SIZE) >> PAGE_SHIFT;
I think it would be more accurate to add it to array_size instead of
doing page rounding here.
> - array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
> + array->map.pages += round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
and this line wouldn't need to change...
next prev parent reply other threads:[~2016-01-11 19:14 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-11 15:56 [PATCH 0/9] bpf: support percpu ARRAY map Ming Lei
2016-01-11 15:56 ` [PATCH 1/9] bpf: prepare for moving map common stuff into one place Ming Lei
2016-01-11 18:24 ` kbuild test robot
2016-01-11 15:56 ` [PATCH 2/9] bpf: array map: use pre-defined nop map function Ming Lei
2016-01-11 19:08 ` Alexei Starovoitov
2016-01-11 15:56 ` [PATCH 3/9] bpf: introduce percpu verion of lookup/update in bpf_map_ops Ming Lei
2016-01-11 15:56 ` [PATCH 4/9] bpf: add percpu version of lookup/update element helpers Ming Lei
2016-01-11 15:56 ` [PATCH 5/9] bpf: syscall: add percpu version of lookup/update elem Ming Lei
2016-01-11 19:02 ` Alexei Starovoitov
2016-01-12 5:00 ` Ming Lei
2016-01-12 5:49 ` Alexei Starovoitov
2016-01-12 11:05 ` Ming Lei
2016-01-12 19:10 ` Martin KaFai Lau
2016-01-13 0:38 ` Ming Lei
2016-01-13 2:22 ` Martin KaFai Lau
2016-01-13 3:17 ` Ming Lei
2016-01-13 5:30 ` Alexei Starovoitov
2016-01-13 14:56 ` Ming Lei
2016-01-14 1:19 ` Alexei Starovoitov
2016-01-14 2:42 ` Ming Lei
2016-01-14 5:08 ` Alexei Starovoitov
2016-01-14 7:16 ` Ming Lei
2016-01-11 15:56 ` [PATCH 6/9] bpf: arraymap: introduce BPF_MAP_TYPE_ARRAY_PERCPU Ming Lei
2016-01-11 19:14 ` Alexei Starovoitov [this message]
2016-01-11 15:56 ` [PATCH 7/9] sample/bpf: introduces helpers for percpu array example Ming Lei
2016-01-11 15:57 ` [PATCH 8/9] sample/bpf: sockex1: user percpu array map Ming Lei
2016-01-11 15:57 ` [PATCH 9/9] samples/bpf: test " Ming Lei
2016-01-12 15:44 ` David Laight
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