Re: [PATCH v2 0/8] kallsyms: Optimizes the performance of lookup symbols
From: Leizhen (ThunderTown)
Date: Thu Sep 15 2022 - 21:27:53 EST
Can anyone review it? Maybe I should split this patch series
into two parts: kallsyms and livepatch.
In fact, the performance can be improved even if the compression policy
of the symbol type is not changed, that is, the scripts/callsyms.c file is
not modified, but we perform the len-based filtering first. That way, it'll
be easier for everyone to review. OK, I'm ready for v3.
On 2022/9/9 21:00, Zhen Lei wrote:
> v1 --> v2:
> Add self-test facility
> Currently, to search for a symbol, we need to expand the symbols in
> 'kallsyms_names' one by one, and then use the expanded string for
> comparison. This is very slow.
> In fact, we can first compress the name being looked up and then use
> it for comparison when traversing 'kallsyms_names'.
> This patch series optimizes the performance of function kallsyms_lookup_name(),
> and function klp_find_object_symbol() in the livepatch module. Based on the
> test results, the performance overhead is reduced to 5%. That is, the
> performance of these functions is improved by 20 times.
> To avoid increasing the kernel size in non-debug mode, the optimization is only
> for the case CONFIG_KALLSYMS_ALL=y.
> Zhen Lei (8):
> scripts/kallsyms: don't compress symbol type when
> scripts/kallsyms: rename build_initial_tok_table()
> kallsyms: Adjust the types of some local variables
> kallsyms: Improve the performance of kallsyms_lookup_name()
> kallsyms: Add helper kallsyms_on_each_match_symbol()
> livepatch: Use kallsyms_on_each_match_symbol() to improve performance
> livepatch: Improve the search performance of
> kallsyms: Add self-test facility
> include/linux/kallsyms.h | 8 ++
> init/Kconfig | 13 ++
> kernel/Makefile | 1 +
> kernel/kallsyms.c | 135 ++++++++++++++++++++-
> kernel/kallsyms_selftest.c | 243 +++++++++++++++++++++++++++++++++++++
> kernel/livepatch/core.c | 25 +++-
> kernel/module/kallsyms.c | 13 +-
> scripts/kallsyms.c | 19 ++-
> 8 files changed, 441 insertions(+), 16 deletions(-)
> create mode 100644 kernel/kallsyms_selftest.c