Add the flags field to stack_print_ctx, and define two flags for current behavior (printing stack traces and their number of base pages). The plumbing of flags is debugfs_create_file(data) -> inode.i_private -> page_owner_stack_open() -> stack_print_ctx.flags -> stack_print(). No behavior change intended. Signed-off-by: Mauricio Faria de Oliveira --- mm/page_owner.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index c1a7d7afe945..e983ac21a4db 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -45,8 +45,12 @@ static struct stack failure_stack; static struct stack *stack_list; static DEFINE_SPINLOCK(stack_list_lock); +#define STACK_PRINT_FLAG_STACK 0x1 +#define STACK_PRINT_FLAG_PAGES 0x2 + struct stack_print_ctx { struct stack *stack; + u8 flags; }; static bool page_owner_enabled __initdata; @@ -901,20 +905,24 @@ static int stack_print(struct seq_file *m, void *v) unsigned long *entries; unsigned long nr_entries; struct stack_record *stack_record = stack->stack_record; + struct stack_print_ctx *ctx = m->private; if (!stack->stack_record) return 0; - nr_entries = stack_record->size; - entries = stack_record->entries; nr_base_pages = refcount_read(&stack_record->count) - 1; if (nr_base_pages < 1 || nr_base_pages < page_owner_pages_threshold) return 0; - for (i = 0; i < nr_entries; i++) - seq_printf(m, " %pS\n", (void *)entries[i]); - seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages); + if (ctx->flags & STACK_PRINT_FLAG_STACK) { + nr_entries = stack_record->size; + entries = stack_record->entries; + for (i = 0; i < nr_entries; i++) + seq_printf(m, " %pS\n", (void *)entries[i]); + } + if (ctx->flags & STACK_PRINT_FLAG_PAGES) + seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages); return 0; } @@ -935,6 +943,13 @@ static int page_owner_stack_open(struct inode *inode, struct file *file) int ret = seq_open_private(file, &page_owner_stack_op, sizeof(struct stack_print_ctx)); + if (!ret) { + struct seq_file *m = file->private_data; + struct stack_print_ctx *ctx = m->private; + + ctx->flags = (uintptr_t) inode->i_private; + } + return ret; } @@ -973,7 +988,9 @@ static int __init pageowner_init(void) debugfs_create_file("page_owner", 0400, NULL, NULL, &proc_page_owner_operations); dir = debugfs_create_dir("page_owner_stacks", NULL); - debugfs_create_file("show_stacks", 0400, dir, NULL, + debugfs_create_file("show_stacks", 0400, dir, + (void *)(STACK_PRINT_FLAG_STACK | + STACK_PRINT_FLAG_PAGES), &page_owner_stack_operations); debugfs_create_file("count_threshold", 0600, dir, NULL, &proc_page_owner_threshold); -- 2.48.1