diff mbox series

[v2,5/7] bootmem: Stop using page->index

Message ID 20241005200121.3231142-6-willy@infradead.org (mailing list archive)
State New
Headers show
Series page->index removals in mm | expand

Commit Message

Matthew Wilcox Oct. 5, 2024, 8:01 p.m. UTC
Encode the type into the bottom four bits of page->private and the
info into the remaining bits.  Also turn the bootmem type into a
named enum.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 arch/x86/mm/init_64.c        |  9 ++++-----
 include/linux/bootmem_info.h | 25 +++++++++++++++++--------
 mm/bootmem_info.c            | 11 ++++++-----
 mm/sparse.c                  |  8 ++++----
 4 files changed, 31 insertions(+), 22 deletions(-)

Comments

kernel test robot Oct. 8, 2024, 6:48 p.m. UTC | #1
Hi Matthew,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on tip/locking/core tip/x86/mm dennis-percpu/for-next linus/master v6.12-rc2 next-20241008]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/mm-Convert-page_to_pgoff-to-page_pgoff/20241006-040239
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20241005200121.3231142-6-willy%40infradead.org
patch subject: [PATCH v2 5/7] bootmem: Stop using page->index
config: x86_64-randconfig-011-20241008 (https://download.01.org/0day-ci/archive/20241009/202410090224.gxQY18rm-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410090224.gxQY18rm-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410090224.gxQY18rm-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/x86/mm/init_64.c: In function 'free_pagetable':
>> arch/x86/mm/init_64.c:992:42: error: implicit declaration of function 'bootmem_type' [-Werror=implicit-function-declaration]
     992 |                 enum bootmem_type type = bootmem_type(page);
         |                                          ^~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/bootmem_type +992 arch/x86/mm/init_64.c

   987	
   988	static void __meminit free_pagetable(struct page *page, int order)
   989	{
   990		/* bootmem page has reserved flag */
   991		if (PageReserved(page)) {
 > 992			enum bootmem_type type = bootmem_type(page);
   993			unsigned long nr_pages = 1 << order;
   994	
   995			if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
   996				while (nr_pages--)
   997					put_page_bootmem(page++);
   998			} else
   999				while (nr_pages--)
  1000					free_reserved_page(page++);
  1001		} else
  1002			free_pages((unsigned long)page_address(page), order);
  1003	}
  1004
kernel test robot Oct. 8, 2024, 7:29 p.m. UTC | #2
Hi Matthew,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on tip/locking/core tip/x86/mm dennis-percpu/for-next linus/master v6.12-rc2 next-20241008]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/mm-Convert-page_to_pgoff-to-page_pgoff/20241006-040239
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20241005200121.3231142-6-willy%40infradead.org
patch subject: [PATCH v2 5/7] bootmem: Stop using page->index
config: x86_64-randconfig-014-20241008 (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/mm/init_64.c:992:28: error: call to undeclared function 'bootmem_type'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     992 |                 enum bootmem_type type = bootmem_type(page);
         |                                          ^
   1 error generated.


vim +/bootmem_type +992 arch/x86/mm/init_64.c

   987	
   988	static void __meminit free_pagetable(struct page *page, int order)
   989	{
   990		/* bootmem page has reserved flag */
   991		if (PageReserved(page)) {
 > 992			enum bootmem_type type = bootmem_type(page);
   993			unsigned long nr_pages = 1 << order;
   994	
   995			if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
   996				while (nr_pages--)
   997					put_page_bootmem(page++);
   998			} else
   999				while (nr_pages--)
  1000					free_reserved_page(page++);
  1001		} else
  1002			free_pages((unsigned long)page_address(page), order);
  1003	}
  1004
Andrew Morton Oct. 9, 2024, 9:34 p.m. UTC | #3
On Wed, 9 Oct 2024 03:29:37 +0800 kernel test robot <lkp@intel.com> wrote:

> Hi Matthew,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on akpm-mm/mm-everything]
> [also build test ERROR on tip/locking/core tip/x86/mm dennis-percpu/for-next linus/master v6.12-rc2 next-20241008]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/mm-Convert-page_to_pgoff-to-page_pgoff/20241006-040239
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20241005200121.3231142-6-willy%40infradead.org
> patch subject: [PATCH v2 5/7] bootmem: Stop using page->index
> config: x86_64-randconfig-014-20241008 (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/config)
> compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410090311.eaqcL7IZ-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> arch/x86/mm/init_64.c:992:28: error: call to undeclared function 'bootmem_type'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>      992 |                 enum bootmem_type type = bootmem_type(page);
>          |                                          ^
>    1 error generated.
> 

Thanks, I did the below.  

I do wonder whether we should be using free_bootmem_page() in the
CONFIG_HAVE_BOOTMEM_INFO_NODE=n case,

And in the CONFIG_HAVE_BOOTMEM_INFO_NODE=y case, the logic in
free_pagetable() looks quite duplicative of the logic in
free_bootmem_page() (which seems too large to be inlined).

My new free_reserved_pages() should be moved elsewhere so riscv and
powerpc (at least) can use it.



From: Andrew Morton <akpm@linux-foundation.org>
Subject: bootmem-stop-using-page-index-fix
Date: Wed Oct  9 02:16:16 PM PDT 2024

fix arch/x86/mm/init_64.c build with !CONFIG_HAVE_BOOTMEM_INFO_NODE

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410090311.eaqcL7IZ-lkp@intel.com/
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/mm/init_64.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

--- a/arch/x86/mm/init_64.c~bootmem-stop-using-page-index-fix
+++ a/arch/x86/mm/init_64.c
@@ -985,21 +985,32 @@ int arch_add_memory(int nid, u64 start,
 	return add_pages(nid, start_pfn, nr_pages, params);
 }
 
+static void free_reserved_pages(struct page *page, unsigned long nr_pages)
+{
+	while (nr_pages--)
+		free_reserved_page(page++);
+}
+
 static void __meminit free_pagetable(struct page *page, int order)
 {
 	/* bootmem page has reserved flag */
 	if (PageReserved(page)) {
-		enum bootmem_type type = bootmem_type(page);
 		unsigned long nr_pages = 1 << order;
+#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
+		enum bootmem_type type = bootmem_type(page);
 
 		if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
 			while (nr_pages--)
 				put_page_bootmem(page++);
-		} else
-			while (nr_pages--)
-				free_reserved_page(page++);
-	} else
+		} else {
+			free_reserved_pages(page, nr_pages);
+		}
+#else
+		free_reserved_pages(page, nr_pages);
+#endif
+	} else {
 		free_pages((unsigned long)page_address(page), order);
+	}
 }
 
 static void __meminit free_hugepage_table(struct page *page,
diff mbox series

Patch

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ff253648706f..4d5fde324136 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -987,13 +987,12 @@  int arch_add_memory(int nid, u64 start, u64 size,
 
 static void __meminit free_pagetable(struct page *page, int order)
 {
-	unsigned long magic;
-	unsigned int nr_pages = 1 << order;
-
 	/* bootmem page has reserved flag */
 	if (PageReserved(page)) {
-		magic = page->index;
-		if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) {
+		enum bootmem_type type = bootmem_type(page);
+		unsigned long nr_pages = 1 << order;
+
+		if (type == SECTION_INFO || type == MIX_SECTION_INFO) {
 			while (nr_pages--)
 				put_page_bootmem(page++);
 		} else
diff --git a/include/linux/bootmem_info.h b/include/linux/bootmem_info.h
index cffa38a73618..e2fe5de93dcc 100644
--- a/include/linux/bootmem_info.h
+++ b/include/linux/bootmem_info.h
@@ -6,11 +6,10 @@ 
 #include <linux/kmemleak.h>
 
 /*
- * Types for free bootmem stored in page->lru.next. These have to be in
- * some random range in unsigned long space for debugging purposes.
+ * Types for free bootmem stored in the low bits of page->private.
  */
-enum {
-	MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 12,
+enum bootmem_type {
+	MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 1,
 	SECTION_INFO = MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE,
 	MIX_SECTION_INFO,
 	NODE_INFO,
@@ -21,9 +20,19 @@  enum {
 void __init register_page_bootmem_info_node(struct pglist_data *pgdat);
 
 void get_page_bootmem(unsigned long info, struct page *page,
-		      unsigned long type);
+		enum bootmem_type type);
 void put_page_bootmem(struct page *page);
 
+static inline enum bootmem_type bootmem_type(const struct page *page)
+{
+	return (unsigned long)page->private & 0xf;
+}
+
+static inline unsigned long bootmem_info(const struct page *page)
+{
+	return (unsigned long)page->private >> 4;
+}
+
 /*
  * Any memory allocated via the memblock allocator and not via the
  * buddy will be marked reserved already in the memmap. For those
@@ -31,7 +40,7 @@  void put_page_bootmem(struct page *page);
  */
 static inline void free_bootmem_page(struct page *page)
 {
-	unsigned long magic = page->index;
+	enum bootmem_type type = bootmem_type(page);
 
 	/*
 	 * The reserve_bootmem_region sets the reserved flag on bootmem
@@ -39,7 +48,7 @@  static inline void free_bootmem_page(struct page *page)
 	 */
 	VM_BUG_ON_PAGE(page_ref_count(page) != 2, page);
 
-	if (magic == SECTION_INFO || magic == MIX_SECTION_INFO)
+	if (type == SECTION_INFO || type == MIX_SECTION_INFO)
 		put_page_bootmem(page);
 	else
 		VM_BUG_ON_PAGE(1, page);
@@ -54,7 +63,7 @@  static inline void put_page_bootmem(struct page *page)
 }
 
 static inline void get_page_bootmem(unsigned long info, struct page *page,
-				    unsigned long type)
+				    enum bootmem_type type)
 {
 }
 
diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c
index fa7cb0c87c03..95f288169a38 100644
--- a/mm/bootmem_info.c
+++ b/mm/bootmem_info.c
@@ -14,23 +14,24 @@ 
 #include <linux/memory_hotplug.h>
 #include <linux/kmemleak.h>
 
-void get_page_bootmem(unsigned long info, struct page *page, unsigned long type)
+void get_page_bootmem(unsigned long info, struct page *page,
+		enum bootmem_type type)
 {
-	page->index = type;
+	BUG_ON(type > 0xf);
+	BUG_ON(info > (ULONG_MAX >> 4));
 	SetPagePrivate(page);
-	set_page_private(page, info);
+	set_page_private(page, info << 4 | type);
 	page_ref_inc(page);
 }
 
 void put_page_bootmem(struct page *page)
 {
-	unsigned long type = page->index;
+	enum bootmem_type type = bootmem_type(page);
 
 	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
 	       type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
 
 	if (page_ref_dec_return(page) == 1) {
-		page->index = 0;
 		ClearPagePrivate(page);
 		set_page_private(page, 0);
 		INIT_LIST_HEAD(&page->lru);
diff --git a/mm/sparse.c b/mm/sparse.c
index dc38539f8560..6ba5354cf2e1 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -720,19 +720,19 @@  static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
 static void free_map_bootmem(struct page *memmap)
 {
 	unsigned long maps_section_nr, removing_section_nr, i;
-	unsigned long magic, nr_pages;
+	unsigned long type, nr_pages;
 	struct page *page = virt_to_page(memmap);
 
 	nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
 		>> PAGE_SHIFT;
 
 	for (i = 0; i < nr_pages; i++, page++) {
-		magic = page->index;
+		type = bootmem_type(page);
 
-		BUG_ON(magic == NODE_INFO);
+		BUG_ON(type == NODE_INFO);
 
 		maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
-		removing_section_nr = page_private(page);
+		removing_section_nr = bootmem_info(page);
 
 		/*
 		 * When this function is called, the removing section is