Commit db42523b authored by Linus Torvalds's avatar Linus Torvalds Committed by Steven Rostedt (VMware)
Browse files

ftrace: Store the order of pages allocated in ftrace_page 

Instead of saving the size of the records field of the ftrace_page, store
the order it uses to allocate the pages, as that is what is needed to know
in order to free the pages. This simplifies the code.

Link: https://lore.kernel.org/lkml/CAHk-=whyMxheOqXAORt9a7JK9gc9eHTgCJ55Pgs4p=X3RrQubQ@mail.gmail.com/



Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
[ change log written by Steven Rostedt ]
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent f3ef7202

kernel/trace/ftrace.c

+17 −18
Original line number Diff line number Diff line
@@ -1090,7 +1090,7 @@ struct ftrace_page { 
	struct ftrace_page	*next;

	struct dyn_ftrace	*records;

	int			index;

	int			size;

	int			order;

};



#define ENTRY_SIZE sizeof(struct dyn_ftrace)
@@ -3181,7 +3181,7 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count) 
	ftrace_number_of_groups++;



	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;

	pg->size = cnt;

	pg->order = order;



	if (cnt > count)

		cnt = count;
@@ -3194,7 +3194,6 @@ ftrace_allocate_pages(unsigned long num_to_init) 
{

	struct ftrace_page *start_pg;

	struct ftrace_page *pg;

	int order;

	int cnt;



	if (!num_to_init)
@@ -3230,13 +3229,13 @@ ftrace_allocate_pages(unsigned long num_to_init) 
 free_pages:

	pg = start_pg;

	while (pg) {

		order = get_count_order(pg->size / ENTRIES_PER_PAGE);

		if (order >= 0)

			free_pages((unsigned long)pg->records, order);

		if (pg->records) {

			free_pages((unsigned long)pg->records, pg->order);

			ftrace_number_of_pages -= 1 << pg->order;

		}

		start_pg = pg->next;

		kfree(pg);

		pg = start_pg;

		ftrace_number_of_pages -= 1 << order;

		ftrace_number_of_groups--;

	}

	pr_info("ftrace: FAILED to allocate memory for functions\n");
@@ -6188,6 +6187,7 @@ static int ftrace_process_locs(struct module *mod, 
	p = start;

	pg = start_pg;

	while (p < end) {

		unsigned long end_offset;

		addr = ftrace_call_adjust(*p++);

		/*

		 * Some architecture linkers will pad between
@@ -6198,7 +6198,8 @@ static int ftrace_process_locs(struct module *mod, 
		if (!addr)

			continue;



		if (pg->index == pg->size) {

		end_offset = (pg->index+1) * sizeof(pg->records[0]);

		if (end_offset > PAGE_SIZE << pg->order) {

			/* We should have allocated enough */

			if (WARN_ON(!pg->next))

				break;
@@ -6367,7 +6368,6 @@ void ftrace_release_mod(struct module *mod) 
	struct ftrace_page **last_pg;

	struct ftrace_page *tmp_page = NULL;

	struct ftrace_page *pg;

	int order;



	mutex_lock(&ftrace_lock);
@@ -6418,12 +6418,12 @@ void ftrace_release_mod(struct module *mod) 
		/* Needs to be called outside of ftrace_lock */

		clear_mod_from_hashes(pg);



		order = get_count_order(pg->size / ENTRIES_PER_PAGE);

		if (order >= 0)

			free_pages((unsigned long)pg->records, order);

		if (pg->records) {

			free_pages((unsigned long)pg->records, pg->order);

			ftrace_number_of_pages -= 1 << pg->order;

		}

		tmp_page = pg->next;

		kfree(pg);

		ftrace_number_of_pages -= 1 << order;

		ftrace_number_of_groups--;

	}

}
@@ -6741,7 +6741,6 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr) 
	struct ftrace_mod_map *mod_map = NULL;

	struct ftrace_init_func *func, *func_next;

	struct list_head clear_hash;

	int order;



	INIT_LIST_HEAD(&clear_hash);
@@ -6779,10 +6778,10 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr) 
		ftrace_update_tot_cnt--;

		if (!pg->index) {

			*last_pg = pg->next;

			order = get_count_order(pg->size / ENTRIES_PER_PAGE);

			if (order >= 0)

				free_pages((unsigned long)pg->records, order);

			ftrace_number_of_pages -= 1 << order;

			if (pg->records) {

				free_pages((unsigned long)pg->records, pg->order);

				ftrace_number_of_pages -= 1 << pg->order;

			}

			ftrace_number_of_groups--;

			kfree(pg);

			pg = container_of(last_pg, struct ftrace_page, next);