From: Peter Zijlstra <peterz@infradead.org>
To: Kris Van Hees <kris.van.hees@oracle.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
dtrace-devel@oss.oracle.com, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, mhiramat@kernel.org, acme@kernel.org,
ast@kernel.org, daniel@iogearbox.net
Subject: Re: [RFC PATCH 00/11] bpf, trace, dtrace: DTrace BPF program type implementation and sample use
Date: Fri, 24 May 2019 09:27:26 +0200 [thread overview]
Message-ID: <20190524072726.GD2589@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190522182215.GO2422@oracle.com>
On Wed, May 22, 2019 at 02:22:15PM -0400, Kris Van Hees wrote:
> > Let me further NAK it for adding all sorts of garbage to the code --
> > we're not going to do gaps and stay_in_page nonsense.
>
> Could you give some guidance in terms of an alternative? The ring buffer code
> provides both non-contiguous page allocation support and a vmalloc-based
> allocation, and the vmalloc version certainly would avoid the entire gap and
> page boundary stuff. But since the allocator is chosen at build time based on
> the arch capabilities, there is no way to select a specific memory allocator.
> I'd be happy to use an alternative approach that allows direct writing into
> the ring buffer.
So why can't you do what the regular perf does? Use an output iterator
that knows about the page breaks? See perf_output_put() for example.
Anyway, I agree with Alexei and DaveM, get it working without/minimal
kernel changes first, and then we can talk about possible optimizations.
next prev parent reply other threads:[~2019-05-24 7:27 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-20 23:47 [RFC PATCH 00/11] bpf, trace, dtrace: DTrace BPF program type implementation and sample use Kris Van Hees
2019-05-21 17:56 ` Alexei Starovoitov
2019-05-21 18:41 ` Kris Van Hees
2019-05-21 20:55 ` Alexei Starovoitov
2019-05-21 21:36 ` Steven Rostedt
2019-05-21 21:43 ` Alexei Starovoitov
2019-05-21 21:48 ` Steven Rostedt
2019-05-22 5:23 ` Kris Van Hees
2019-05-22 20:53 ` Alexei Starovoitov
2019-05-23 5:46 ` Kris Van Hees
2019-05-23 21:13 ` Alexei Starovoitov
2019-05-23 23:02 ` Steven Rostedt
2019-05-24 0:31 ` Alexei Starovoitov
2019-05-24 1:57 ` Steven Rostedt
2019-05-24 2:08 ` Alexei Starovoitov
2019-05-24 2:40 ` Steven Rostedt
2019-05-24 5:26 ` Kris Van Hees
2019-05-24 5:10 ` Kris Van Hees
2019-05-24 4:05 ` Kris Van Hees
2019-05-24 13:28 ` Steven Rostedt
2019-05-21 21:36 ` Kris Van Hees
2019-05-21 23:26 ` Alexei Starovoitov
2019-05-22 4:12 ` Kris Van Hees
2019-05-22 20:16 ` Alexei Starovoitov
2019-05-23 5:16 ` Kris Van Hees
2019-05-23 20:28 ` Alexei Starovoitov
2019-05-30 16:15 ` Kris Van Hees
2019-05-31 15:25 ` Chris Mason
2019-06-06 20:58 ` Kris Van Hees
2019-06-18 1:25 ` Kris Van Hees
2019-06-18 1:32 ` Alexei Starovoitov
2019-06-18 1:54 ` Kris Van Hees
2019-06-18 3:01 ` Alexei Starovoitov
2019-06-18 3:19 ` Kris Van Hees
2019-05-22 14:25 ` Peter Zijlstra
2019-05-22 18:22 ` Kris Van Hees
2019-05-22 19:55 ` Alexei Starovoitov
2019-05-22 20:20 ` David Miller
2019-05-23 5:19 ` Kris Van Hees
2019-05-24 7:27 ` Peter Zijlstra [this message]
2019-05-21 20:39 ` [RFC PATCH 01/11] bpf: context casting for tail call Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 02/11] bpf: add BPF_PROG_TYPE_DTRACE Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 03/11] bpf: export proto for bpf_perf_event_output helper Kris Van Hees
[not found] ` <facilities>
2019-05-21 20:39 ` [RFC PATCH 04/11] trace: initial implementation of DTrace based on kernel Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 05/11] trace: update Kconfig and Makefile to include DTrace Kris Van Hees
[not found] ` <features>
2019-05-21 20:39 ` [RFC PATCH 06/11] dtrace: tiny userspace tool to exercise DTrace support Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 07/11] bpf: implement writable buffers in contexts Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 08/11] perf: add perf_output_begin_forward_in_page Kris Van Hees
[not found] ` <the>
[not found] ` <context>
2019-05-21 20:39 ` [RFC PATCH 09/11] bpf: mark helpers explicitly whether they may change Kris Van Hees
[not found] ` <helpers>
2019-05-21 20:39 ` [RFC PATCH 10/11] bpf: add bpf_buffer_reserve and bpf_buffer_commit Kris Van Hees
2019-05-21 20:40 ` [RFC PATCH 11/11] dtrace: make use of writable buffers in BPF Kris Van Hees
2019-05-21 20:48 ` [RFC PATCH 00/11] bpf, trace, dtrace: DTrace BPF program type implementation and sample use Kris Van Hees
2019-05-21 20:54 ` Steven Rostedt
2019-05-21 20:56 ` Alexei Starovoitov
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