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    Subject[PATCH v3 6/8] livepatch: Use kallsyms_on_each_match_symbol() to improve performance
    Date
    Based on the test results of kallsyms_on_each_match_symbol() and
    kallsyms_on_each_symbol(), the average performance can be improved by 20
    to 30 times.

    Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
    ---
    kernel/livepatch/core.c | 20 +++++++++++++++++++-
    1 file changed, 19 insertions(+), 1 deletion(-)

    diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
    index 42f7e716d56bf72..31b57ccf908017e 100644
    --- a/kernel/livepatch/core.c
    +++ b/kernel/livepatch/core.c
    @@ -153,6 +153,24 @@ static int klp_find_callback(void *data, const char *name,
    return 0;
    }

    +static int klp_match_callback(void *data, unsigned long addr)
    +{
    + struct klp_find_arg *args = data;
    +
    + args->addr = addr;
    + args->count++;
    +
    + /*
    + * Finish the search when the symbol is found for the desired position
    + * or the position is not defined for a non-unique symbol.
    + */
    + if ((args->pos && (args->count == args->pos)) ||
    + (!args->pos && (args->count > 1)))
    + return 1;
    +
    + return 0;
    +}
    +
    static int klp_find_object_symbol(const char *objname, const char *name,
    unsigned long sympos, unsigned long *addr)
    {
    @@ -167,7 +185,7 @@ static int klp_find_object_symbol(const char *objname, const char *name,
    if (objname)
    module_kallsyms_on_each_symbol(klp_find_callback, &args);
    else
    - kallsyms_on_each_symbol(klp_find_callback, &args);
    + kallsyms_on_each_match_symbol(klp_match_callback, name, &args);

    /*
    * Ensure an address was found. If sympos is 0, ensure symbol is unique;
    --
    2.25.1
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      Last update: 2022-09-19 17:18    [W:4.027 / U:0.276 seconds]
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