[ Upstream commit 4dc533e0f2c04174e1ae4aa98e7cffc1c04b9998 ]
Function kallsyms_on_each_symbol() traverses all symbols and submits each
symbol to the hook 'fn' for judgment and processing. For some cases, the
hook actually only handles the matched symbol, such as livepatch.
Because all symbols are currently sorted by name, all the symbols with the
same name are clustered together. Function kallsyms_lookup_names() gets
the start and end positions of the set corresponding to the specified
name. So we can easily and quickly traverse all the matches.
The test results are as follows (twice): (x86)
kallsyms_on_each_match_symbol: 7454, 7984
kallsyms_on_each_symbol : 11733809, 11785803
kallsyms_on_each_match_symbol() consumes only 0.066% of
kallsyms_on_each_symbol()'s time. In other words, 1523x better
performance.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Stable-dep-of: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols")
Signed-off-by: Sasha Levin <sashal@kernel.org>
e9b4b72567