From 4c85c0be3d7a9a7ffe48bfe0954eacc0ba9d3c75 Mon Sep 17 00:00:00 2001 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> Date: Mon, 30 Jan 2023 13:25:13 +0900 Subject: mm, printk: introduce new format %pGt for page_type %pGp format is used to display 'flags' field of a struct page. However, some page flags (i.e. PG_buddy, see page-flags.h for more details) are stored in page_type field. To display human-readable output of page_type, introduce %pGt format. It is important to note the meaning of bits are different in page_type. if page_type is 0xffffffff, no flags are set. Setting PG_buddy (0x00000080) flag results in a page_type of 0xffffff7f. Clearing a bit actually means setting a flag. Bits in page_type are inverted when displaying type names. Only values for which page_type_has_type() returns true are considered as page_type, to avoid confusion with mapcount values. if it returns false, only raw values are displayed and not page type names. Link: https://lkml.kernel.org/r/20230130042514.2418-3-42.hyeyoo@gmail.com Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Petr Mladek [vsprintf part] Cc: Andy Shevchenko Cc: David Hildenbrand Cc: Joe Perches Cc: John Ogness Cc: Matthew Wilcox Cc: Sergey Senozhatsky Cc: Steven Rostedt (Google) Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- lib/test_printf.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'lib/test_printf.c') diff --git a/lib/test_printf.c b/lib/test_printf.c index 46b4e6c414a3..7677ebccf3c3 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -642,12 +642,26 @@ page_flags_test(int section, int node, int zone, int last_cpupid, test(cmp_buf, "%pGp", &flags); } +static void __init page_type_test(unsigned int page_type, const char *name, + char *cmp_buf) +{ + unsigned long size; + + size = scnprintf(cmp_buf, BUF_SIZE, "%#x(", page_type); + if (page_type_has_type(page_type)) + size += scnprintf(cmp_buf + size, BUF_SIZE - size, "%s", name); + + snprintf(cmp_buf + size, BUF_SIZE - size, ")"); + test(cmp_buf, "%pGt", &page_type); +} + static void __init flags(void) { unsigned long flags; char *cmp_buffer; gfp_t gfp; + unsigned int page_type; cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL); if (!cmp_buffer) @@ -687,6 +701,18 @@ flags(void) gfp |= __GFP_HIGH; test(cmp_buffer, "%pGg", &gfp); + page_type = ~0; + page_type_test(page_type, "", cmp_buffer); + + page_type = 10; + page_type_test(page_type, "", cmp_buffer); + + page_type = ~PG_buddy; + page_type_test(page_type, "buddy", cmp_buffer); + + page_type = ~(PG_table | PG_buddy); + page_type_test(page_type, "table|buddy", cmp_buffer); + kfree(cmp_buffer); } -- cgit v1.2.3