From: patchwork-bot+netdevbpf@kernel.org
To: Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, kernel-team@meta.com, mhiramat@kernel.org,
peterz@infradead.org
Subject: Re: [PATCH bpf-next] bpf: avoid get_kernel_nofault() to fetch kprobe entry IP
Date: Mon, 25 Mar 2024 16:10:28 +0000 [thread overview]
Message-ID: <171138302899.9923.3323757238369450275.git-patchwork-notify@kernel.org> (raw)
In-Reply-To: <20240319212013.1046779-1-andrii@kernel.org>
Hello:
This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:
On Tue, 19 Mar 2024 14:20:13 -0700 you wrote:
> get_kernel_nofault() (or, rather, underlying copy_from_kernel_nofault())
> is not free and it does pop up in performance profiles when
> kprobes are heavily utilized with CONFIG_X86_KERNEL_IBT=y config.
>
> Let's avoid using it if we know that fentry_ip - 4 can't cross page
> boundary. We do that by masking lowest 12 bits and checking if they are
> >= 4, in which case we can do direct memory read.
>
> [...]
Here is the summary with links:
- [bpf-next] bpf: avoid get_kernel_nofault() to fetch kprobe entry IP
https://git.kernel.org/bpf/bpf-next/c/a8497506cd2c
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
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prev parent reply other threads:[~2024-03-25 16:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-19 21:20 [PATCH bpf-next] bpf: avoid get_kernel_nofault() to fetch kprobe entry IP Andrii Nakryiko
2024-03-20 3:47 ` Masami Hiramatsu
2024-03-20 8:34 ` Jiri Olsa
2024-03-20 17:46 ` Andrii Nakryiko
2024-03-20 23:46 ` Masami Hiramatsu
2024-03-21 16:16 ` Andrii Nakryiko
2024-03-25 16:10 ` patchwork-bot+netdevbpf [this message]
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