From b40c6eabfcd409e022fcb377ac268e3ef9446fde Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Mon, 31 Aug 2020 11:11:02 +0800 Subject: ftrace: Simplify the calculation of page number for ftrace_page->records Based on the following two reasones, we could simplify the calculation: - If the number after roundup count is not power of 2, we would definitely have more than 1 empty page with a higher order. - get_count_order() just return current order, so one lower order could meet the requirement. The calculation could be simplified by lower one order level when pages are not power of 2. Link: https://lkml.kernel.org/r/20200831031104.23322-5-richard.weiyang@linux.alibaba.com Signed-off-by: Wei Yang Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel/trace') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index c51a91aea1fd..c3be18b4f27b 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3129,18 +3129,19 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) static int ftrace_allocate_records(struct ftrace_page *pg, int count) { int order; - int cnt; + int pages, cnt; if (WARN_ON(!count)) return -EINVAL; - order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); + pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE); + order = get_count_order(pages); /* * We want to fill as much as possible. No more than a page * may be empty. */ - while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE) + if (!is_power_of_2(pages)) order--; again: -- cgit v1.2.3