From: Zhen Lei <thunder.leizhen@huawei.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
<live-patching@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Alexei Starovoitov <ast@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Luis Chamberlain" <mcgrof@kernel.org>,
<linux-modules@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Subject: [PATCH 6/7] livepatch: Use kallsyms_on_each_match_symbol() to improve performance
Date: Thu, 8 Sep 2022 21:09:35 +0800 [thread overview]
Message-ID: <20220908130936.674-7-thunder.leizhen@huawei.com> (raw)
In-Reply-To: <20220908130936.674-1-thunder.leizhen@huawei.com>
Based on the test results of kallsyms_on_each_match_symbol() and
kallsyms_on_each_symbol(), this can reduce the performance overhead by
approximately 95%, if CONFIG_KALLSYMS_ALL=y.
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
next prev parent reply other threads:[~2022-09-08 13:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 13:09 [PATCH 0/7] kallsyms: Optimizes the performance of lookup symbols Zhen Lei
2022-09-08 13:09 ` [PATCH 1/7] scripts/kallsyms: don't compress symbol type when CONFIG_KALLSYMS_ALL=y Zhen Lei
2022-09-08 13:09 ` [PATCH 2/7] scripts/kallsyms: rename build_initial_tok_table() Zhen Lei
2022-09-08 13:09 ` [PATCH 3/7] kallsyms: Adjust the types of some local variables Zhen Lei
2022-09-08 13:09 ` [PATCH 4/7] kallsyms: Improve the performance of kallsyms_lookup_name() Zhen Lei
2022-09-08 13:09 ` [PATCH 5/7] kallsyms: Add helper kallsyms_on_each_match_symbol() Zhen Lei
2022-09-08 13:09 ` Zhen Lei [this message]
2022-09-08 13:09 ` [PATCH 7/7] livepatch: Improve the search performance of module_kallsyms_on_each_symbol() Zhen Lei
2022-09-09 0:07 ` [PATCH 0/7] kallsyms: Optimizes the performance of lookup symbols Luis Chamberlain
2022-09-09 1:17 ` Leizhen (ThunderTown)
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