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authorHyeonggon Yoo <42.hyeyoo@gmail.com>2023-01-30 13:25:13 +0900
committerAndrew Morton <akpm@linux-foundation.org>2023-03-28 16:20:09 -0700
commit4c85c0be3d7a9a7ffe48bfe0954eacc0ba9d3c75 (patch)
tree5a70b48802c32e4d22ab234cac075450a0364734 /lib
parente26fcc02c7f6c76cba42d043756e35a78ce9ac11 (diff)
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 <pmladek@suse.com> [vsprintf part] Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_printf.c26
-rw-r--r--lib/vsprintf.c21
2 files changed, 47 insertions, 0 deletions
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);
}
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index be71a03c936a..fbe320b5e89f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2052,6 +2052,25 @@ char *format_page_flags(char *buf, char *end, unsigned long flags)
return buf;
}
+static
+char *format_page_type(char *buf, char *end, unsigned int page_type)
+{
+ buf = number(buf, end, page_type, default_flag_spec);
+
+ if (buf < end)
+ *buf = '(';
+ buf++;
+
+ if (page_type_has_type(page_type))
+ buf = format_flags(buf, end, ~page_type, pagetype_names);
+
+ if (buf < end)
+ *buf = ')';
+ buf++;
+
+ return buf;
+}
+
static noinline_for_stack
char *flags_string(char *buf, char *end, void *flags_ptr,
struct printf_spec spec, const char *fmt)
@@ -2065,6 +2084,8 @@ char *flags_string(char *buf, char *end, void *flags_ptr,
switch (fmt[1]) {
case 'p':
return format_page_flags(buf, end, *(unsigned long *)flags_ptr);
+ case 't':
+ return format_page_type(buf, end, *(unsigned int *)flags_ptr);
case 'v':
flags = *(unsigned long *)flags_ptr;
names = vmaflag_names;