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authorZhen Lei <thunder.leizhen@huawei.com>2023-01-16 11:10:07 +0100
committerAlexei Starovoitov <ast@kernel.org>2023-01-19 17:07:15 -0800
commit07cc2c931e8e1083a31f4c51d2244fe264af63bf (patch)
tree1abb9ab286d6310e872dcb99448c65bd10a85748 /kernel/livepatch
parent92afc5329a5b23d876b215b783d200352d5aaea6 (diff)
livepatch: Improve the search performance of module_kallsyms_on_each_symbol()
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). Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Song Liu <song@kernel.org> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20230116101009.23694-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/core.c10
1 files changed, 1 insertions, 9 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 201f0c0482fb..c973ed9e42f8 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -118,7 +118,6 @@ static struct klp_object *klp_find_object(struct klp_patch *patch,
}
struct klp_find_arg {
- const char *objname;
const char *name;
unsigned long addr;
unsigned long count;
@@ -148,15 +147,9 @@ static int klp_find_callback(void *data, const char *name,
{
struct klp_find_arg *args = data;
- if ((mod && !args->objname) || (!mod && args->objname))
- return 0;
-
if (strcmp(args->name, name))
return 0;
- if (args->objname && strcmp(args->objname, mod->name))
- return 0;
-
return klp_match_callback(data, addr);
}
@@ -164,7 +157,6 @@ static int klp_find_object_symbol(const char *objname, const char *name,
unsigned long sympos, unsigned long *addr)
{
struct klp_find_arg args = {
- .objname = objname,
.name = name,
.addr = 0,
.count = 0,
@@ -172,7 +164,7 @@ static int klp_find_object_symbol(const char *objname, const char *name,
};
if (objname)
- module_kallsyms_on_each_symbol(klp_find_callback, &args);
+ module_kallsyms_on_each_symbol(objname, klp_find_callback, &args);
else
kallsyms_on_each_match_symbol(klp_match_callback, name, &args);