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authorWei Yang <richard.weiyang@linux.alibaba.com>2020-08-31 11:11:02 +0800
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-10-08 15:29:06 -0400
commitb40c6eabfcd409e022fcb377ac268e3ef9446fde (patch)
tree9f5cf98fcd3a13f2951d7d2b8c0cc12ffec45738 /kernel/trace
parent02dae28f0b542969e44cbc1e14ffc9944cd2975c (diff)
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 <richard.weiyang@linux.alibaba.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ftrace.c7
1 files changed, 4 insertions, 3 deletions
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--;
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