Thread (21 messages) 21 messages, 4 authors, 2023-01-11

Re: [PATCH 1/3] livepatch: Improve the search performance of module_kallsyms_on_each_symbol()

From: Petr Mladek <pmladek@suse.com>
Date: 2023-01-04 15:36:38
Also in: bpf, linux-trace-kernel, live-patching, lkml

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 <redacted>
Looks good to me:

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

Best Regards,
Petr
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