printf: remove %pGt support

Patch series "Increase the number of bits available in page_type".

Kent wants more than 16 bits in page_type, so I resurrected this old patch
and expanded it a bit.  It's a bit more efficient than our current scheme
(1 4-byte insn vs 3 insns of 13 bytes total) to test a single page type.


This patch (of 4):

An upcoming patch will convert page type from being a bitfield to a
single byte, so we will not be able to use %pG to print the page type
any more.  The printing of the symbolic name will be restored in that
patch.

Link: https://lkml.kernel.org/r/20240821173914.2270383-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240821173914.2270383-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/core-api/printk-formats.rst

@@ -576,13 +576,12 @@ The field width is passed by value, the bitmap is passed by reference.
 Helper macros cpumask_pr_args() and nodemask_pr_args() are available to ease
 printing cpumask and nodemask.
 
-Flags bitfields such as page flags, page_type, gfp_flags
+Flags bitfields such as page flags and gfp_flags
 --------------------------------------------------------
 
 ::
 
 	%pGp	0x17ffffc0002036(referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff)
-	%pGt	0xffffff7f(buddy)
 	%pGg	GFP_USER|GFP_DMA32|GFP_NOWARN
 	%pGv	read|exec|mayread|maywrite|mayexec|denywrite
 
@@ -591,7 +590,6 @@ would construct the value. The type of flags is given by the third
 character. Currently supported are:
 
         - p - [p]age flags, expects value of type (``unsigned long *``)
-        - t - page [t]ype, expects value of type (``unsigned int *``)
         - v - [v]ma_flags, expects value of type (``unsigned long *``)
         - g - [g]fp_flags, expects value of type (``gfp_t *``)
 

include/trace/events/mmflags.h

@@ -130,16 +130,6 @@ IF_HAVE_PG_ARCH_X(arch_3)
 	__def_pageflag_names						\
 	) : "none"
 
-#define DEF_PAGETYPE_NAME(_name) { PG_##_name, __stringify(_name) }
-
-#define __def_pagetype_names						\
-	DEF_PAGETYPE_NAME(slab),					\
-	DEF_PAGETYPE_NAME(hugetlb),					\
-	DEF_PAGETYPE_NAME(offline),					\
-	DEF_PAGETYPE_NAME(guard),					\
-	DEF_PAGETYPE_NAME(table),					\
-	DEF_PAGETYPE_NAME(buddy)
-
 #if defined(CONFIG_X86)
 #define __VM_ARCH_SPECIFIC_1 {VM_PAT,     "pat"           }
 #elif defined(CONFIG_PPC)

lib/test_printf.c

@@ -641,26 +641,12 @@ 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)
@@ -700,18 +686,6 @@ 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);
 }
 

lib/vsprintf.c

@@ -2054,25 +2054,6 @@ 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)
@@ -2086,8 +2067,6 @@ 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;

mm/debug.c

@@ -92,7 +92,7 @@ static void __dump_folio(struct folio *folio, struct page *page,
 	pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
 		is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
 	if (page_has_type(&folio->page))
-		pr_warn("page_type: %pGt\n", &folio->page.page_type);
+		pr_warn("page_type: %x\n", folio->page.page_type);
 
 	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
 			sizeof(unsigned long), page,

mm/internal.h

@@ -1144,7 +1144,6 @@ static inline void flush_tlb_batched_pending(struct mm_struct *mm)
 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
 
 extern const struct trace_print_flags pageflag_names[];
-extern const struct trace_print_flags pagetype_names[];
 extern const struct trace_print_flags vmaflag_names[];
 extern const struct trace_print_flags gfpflag_names[];