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From: Petr Mladek <pmladek@suse.com>
To: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
	Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
	Luis Chamberlain <mcgrof@kernel.org>,
	linux-modules@vger.kernel.org
Subject: Re: [PATCH 1/3] livepatch: Improve the search performance of module_kallsyms_on_each_symbol()
Date: Wed, 4 Jan 2023 16:36:28 +0100	[thread overview]
Message-ID: <Y7Wc/G8a+pv6iV7G@alley> (raw)
In-Reply-To: <20221230112729.351-2-thunder.leizhen@huawei.com>

On Fri 2022-12-30 19:27:27, Zhen Lei wrote:
> Currently we traverse all symbols of all modules to find the specified
> function for the specified module. But in reality, we just need to find
> the given module and then traverse all the symbols in it.
> 
> Let's add a new parameter 'const char *modname' to function
> module_kallsyms_on_each_symbol(), then we can compare the module names
> directly in this function and call hook 'fn' after matching. If 'modname'
> is NULL, the symbols of all modules are still traversed for compatibility
> with other usage cases.
> 
> Phase1: mod1-->mod2..(subsequent modules do not need to be compared)
>                 |
> Phase2:          -->f1-->f2-->f3
> 
> Assuming that there are m modules, each module has n symbols on average,
> then the time complexity is reduced from O(m * n) to O(m) + O(n).
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

Looks good to me:

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr

  reply	other threads:[~2023-01-04 15:36 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-30 11:27 [PATCH 0/3] kallsyms: Optimize the search for module symbols by livepatch and bpf Zhen Lei
2022-12-30 11:27 ` [PATCH 1/3] livepatch: Improve the search performance of module_kallsyms_on_each_symbol() Zhen Lei
2023-01-04 15:36   ` Petr Mladek [this message]
2022-12-30 11:27 ` [PATCH 2/3] bpf: Optimize get_modules_for_addrs() Zhen Lei
2023-01-04 16:25   ` Petr Mladek
2023-01-04 17:07     ` Song Liu
2023-01-05  7:31       ` Leizhen (ThunderTown)
2023-01-05  9:05       ` Petr Mladek
2023-01-09  4:02         ` Leizhen (ThunderTown)
2023-01-05  7:48     ` Leizhen (ThunderTown)
2023-01-05  9:32     ` Petr Mladek
2023-01-09  4:10       ` Leizhen (ThunderTown)
2023-01-05 21:31     ` Jiri Olsa
2023-01-06  9:45       ` Jiri Olsa
2023-01-09  8:51         ` Leizhen (ThunderTown)
2023-01-09 13:48           ` Jiri Olsa
2023-01-09 15:11             ` Leizhen (ThunderTown)
2023-01-11  8:41               ` Leizhen (ThunderTown)
2023-01-11  9:53                 ` Jiri Olsa
2023-01-09  7:03       ` Leizhen (ThunderTown)
2022-12-30 11:27 ` [PATCH 3/3] kallsyms: Delete an unused parameter related to {module_}kallsyms_on_each_symbol() Zhen Lei

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