diff options
| -rw-r--r-- | kernel/trace/ftrace.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 413310912609..7eac1472cc57 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -9267,6 +9267,15 @@ static int kallsyms_callback(void *data, const char *name, unsigned long addr) * @addrs array, which needs to be big enough to store at least @cnt * addresses. * + * For a single symbol (cnt == 1), uses kallsyms_lookup_name() which + * performs an O(log N) binary search via the sorted kallsyms index. + * This avoids the full O(N) linear scan over all kernel symbols that + * the multi-symbol path requires. + * + * For multiple symbols, uses a single-pass linear scan via + * kallsyms_on_each_symbol() with binary search into the sorted input + * array. + * * Returns: 0 if all provided symbols are found, -ESRCH otherwise. */ int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs) @@ -9274,6 +9283,19 @@ int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *a struct kallsyms_data args; int found_all; + /* Fast path: single symbol uses O(log N) binary search */ + if (cnt == 1) { + addrs[0] = kallsyms_lookup_name(sorted_syms[0]); + if (addrs[0] && ftrace_location(addrs[0])) + return 0; + /* + * Binary lookup can fail for duplicate symbol names + * where the first match is not ftrace-instrumented. + * Retry with linear scan. + */ + } + + /* Batch path: single-pass O(N) linear scan */ memset(addrs, 0, sizeof(*addrs) * cnt); args.addrs = addrs; args.syms = sorted_syms; |