diff options
Diffstat (limited to 'kernel/trace/ftrace.c')
| -rw-r--r-- | kernel/trace/ftrace.c | 84 |
1 files changed, 64 insertions, 20 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6b0c25761ccb..92015de6203d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -540,6 +540,7 @@ static int function_stat_show(struct seq_file *m, void *v) static struct trace_seq s; unsigned long long avg; unsigned long long stddev; + unsigned long long stddev_denom; #endif guard(mutex)(&ftrace_profile_lock); @@ -559,23 +560,19 @@ static int function_stat_show(struct seq_file *m, void *v) #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_puts(m, " "); - /* Sample standard deviation (s^2) */ - if (rec->counter <= 1) - stddev = 0; - else { - /* - * Apply Welford's method: - * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) - */ + /* + * Variance formula: + * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) + * Maybe Welford's method is better here? + * Divide only by 1000 for ns^2 -> us^2 conversion. + * trace_print_graph_duration will divide by 1000 again. + */ + stddev = 0; + stddev_denom = rec->counter * (rec->counter - 1) * 1000; + if (stddev_denom) { stddev = rec->counter * rec->time_squared - rec->time * rec->time; - - /* - * Divide only 1000 for ns^2 -> us^2 conversion. - * trace_print_graph_duration will divide 1000 again. - */ - stddev = div64_ul(stddev, - rec->counter * (rec->counter - 1) * 1000); + stddev = div64_ul(stddev, stddev_denom); } trace_seq_init(&s); @@ -1296,6 +1293,8 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash) void ftrace_free_filter(struct ftrace_ops *ops) { ftrace_ops_init(ops); + if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) + return; free_ftrace_hash(ops->func_hash->filter_hash); free_ftrace_hash(ops->func_hash->notrace_hash); } @@ -7019,6 +7018,7 @@ static int ftrace_process_locs(struct module *mod, unsigned long *p; unsigned long addr; unsigned long flags = 0; /* Shut up gcc */ + unsigned long pages; int ret = -ENOMEM; count = end - start; @@ -7026,6 +7026,8 @@ static int ftrace_process_locs(struct module *mod, if (!count) return 0; + pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE); + /* * Sorting mcount in vmlinux at build time depend on * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in @@ -7070,7 +7072,9 @@ static int ftrace_process_locs(struct module *mod, pg = start_pg; while (p < end) { unsigned long end_offset; - addr = ftrace_call_adjust(*p++); + + addr = *p++; + /* * Some architecture linkers will pad between * the different mcount_loc sections of different @@ -7082,6 +7086,19 @@ static int ftrace_process_locs(struct module *mod, continue; } + /* + * If this is core kernel, make sure the address is in core + * or inittext, as weak functions get zeroed and KASLR can + * move them to something other than zero. It just will not + * move it to an area where kernel text is. + */ + if (!mod && !(is_kernel_text(addr) || is_kernel_inittext(addr))) { + skipped++; + continue; + } + + addr = ftrace_call_adjust(addr); + end_offset = (pg->index+1) * sizeof(pg->records[0]); if (end_offset > PAGE_SIZE << pg->order) { /* We should have allocated enough */ @@ -7121,11 +7138,41 @@ static int ftrace_process_locs(struct module *mod, /* We should have used all pages unless we skipped some */ if (pg_unuse) { - WARN_ON(!skipped); + unsigned long pg_remaining, remaining = 0; + unsigned long skip; + + /* Count the number of entries unused and compare it to skipped. */ + pg_remaining = (ENTRIES_PER_PAGE << pg->order) - pg->index; + + if (!WARN(skipped < pg_remaining, "Extra allocated pages for ftrace")) { + + skip = skipped - pg_remaining; + + for (pg = pg_unuse; pg; pg = pg->next) + remaining += 1 << pg->order; + + pages -= remaining; + + skip = DIV_ROUND_UP(skip, ENTRIES_PER_PAGE); + + /* + * Check to see if the number of pages remaining would + * just fit the number of entries skipped. + */ + WARN(skip != remaining, "Extra allocated pages for ftrace: %lu with %lu skipped", + remaining, skipped); + } /* Need to synchronize with ftrace_location_range() */ synchronize_rcu(); ftrace_free_pages(pg_unuse); } + + if (!mod) { + count -= skipped; + pr_info("ftrace: allocating %ld entries in %ld pages\n", + count, pages); + } + return ret; } @@ -7771,9 +7818,6 @@ void __init ftrace_init(void) goto failed; } - pr_info("ftrace: allocating %ld entries in %ld pages\n", - count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); - ret = ftrace_process_locs(NULL, __start_mcount_loc, __stop_mcount_loc); |