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authorMichal Hocko <mhocko@suse.com>2017-11-15 17:34:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-15 18:21:03 -0800
commit8745808fda84c638e45cc860c8fb600bf4b0a2a6 (patch)
tree4cc0a5ff3ccf76e73b2fa4bd535e40f261e79e0b /arch
parenta2e16731728a285bcfcece0feaaa8cf478d24022 (diff)
mm, arch: remove empty_bad_page*
empty_bad_page() and empty_bad_pte_table() seem to be relics from old days which is not used by any code for a long time. I have tried to find when exactly but this is not really all that straightforward due to many code movements - traces disappear around 2.4 times. Anyway no code really references neither empty_bad_page nor empty_bad_pte_table. We only allocate the storage which is not used by anybody so remove them. Link: http://lkml.kernel.org/r/20171004150045.30755-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Ralf Baechle <ralf@linus-mips.org> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: David Howells <dhowells@redhat.com> Cc: Rich Felker <dalias@libc.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/frv/mm/init.c14
-rw-r--r--arch/h8300/mm/init.c13
-rw-r--r--arch/mips/include/asm/pgtable-64.h8
-rw-r--r--arch/mn10300/kernel/head.S8
-rw-r--r--arch/sh/kernel/head_64.S8
-rw-r--r--arch/um/kernel/mem.c3
6 files changed, 1 insertions, 53 deletions
diff --git a/arch/frv/mm/init.c b/arch/frv/mm/init.c
index 328f0a292316..cf464100e838 100644
--- a/arch/frv/mm/init.c
+++ b/arch/frv/mm/init.c
@@ -42,21 +42,9 @@
#undef DEBUG
/*
- * BAD_PAGE is the page that is used for page faults when linux
- * is out-of-memory. Older versions of linux just did a
- * do_exit(), but using this instead means there is less risk
- * for a process dying in kernel mode, possibly leaving a inode
- * unused etc..
- *
- * BAD_PAGETABLE is the accompanying page-table: it is initialized
- * to point to BAD_PAGE entries.
- *
* ZERO_PAGE is a special page that is used for zero-initialized
* data and COW.
*/
-static unsigned long empty_bad_page_table;
-static unsigned long empty_bad_page;
-
unsigned long empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);
@@ -72,8 +60,6 @@ void __init paging_init(void)
unsigned long zones_size[MAX_NR_ZONES] = {0, };
/* allocate some pages for kernel housekeeping tasks */
- empty_bad_page_table = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
- empty_bad_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
memset((void *) empty_zero_page, 0, PAGE_SIZE);
diff --git a/arch/h8300/mm/init.c b/arch/h8300/mm/init.c
index eeead51bed2d..015287ac8ce8 100644
--- a/arch/h8300/mm/init.c
+++ b/arch/h8300/mm/init.c
@@ -40,20 +40,9 @@
#include <asm/sections.h>
/*
- * BAD_PAGE is the page that is used for page faults when linux
- * is out-of-memory. Older versions of linux just did a
- * do_exit(), but using this instead means there is less risk
- * for a process dying in kernel mode, possibly leaving a inode
- * unused etc..
- *
- * BAD_PAGETABLE is the accompanying page-table: it is initialized
- * to point to BAD_PAGE entries.
- *
* ZERO_PAGE is a special page that is used for zero-initialized
* data and COW.
*/
-static unsigned long empty_bad_page_table;
-static unsigned long empty_bad_page;
unsigned long empty_zero_page;
/*
@@ -78,8 +67,6 @@ void __init paging_init(void)
* Initialize the bad page table and bad page to point
* to a couple of allocated pages.
*/
- empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
- empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
memset((void *)empty_zero_page, 0, PAGE_SIZE);
diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index 67fe6dc5211c..0036ea0c7173 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -31,12 +31,7 @@
* tables. Each page table is also a single 4K page, giving 512 (==
* PTRS_PER_PTE) 8 byte ptes. Each pud entry is initialized to point to
* invalid_pmd_table, each pmd entry is initialized to point to
- * invalid_pte_table, each pte is initialized to 0. When memory is low,
- * and a pmd table or a page table allocation fails, empty_bad_pmd_table
- * and empty_bad_page_table is returned back to higher layer code, so
- * that the failure is recognized later on. Linux does not seem to
- * handle these failures very well though. The empty_bad_page_table has
- * invalid pte entries in it, to force page faults.
+ * invalid_pte_table, each pte is initialized to 0.
*
* Kernel mappings: kernel mappings are held in the swapper_pg_table.
* The layout is identical to userspace except it's indexed with the
@@ -175,7 +170,6 @@
printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
extern pte_t invalid_pte_table[PTRS_PER_PTE];
-extern pte_t empty_bad_page_table[PTRS_PER_PTE];
#ifndef __PAGETABLE_PUD_FOLDED
/*
diff --git a/arch/mn10300/kernel/head.S b/arch/mn10300/kernel/head.S
index 73e00fc78072..0b15f759e0d2 100644
--- a/arch/mn10300/kernel/head.S
+++ b/arch/mn10300/kernel/head.S
@@ -434,14 +434,6 @@ ENTRY(empty_zero_page)
.space PAGE_SIZE
.balign PAGE_SIZE
-ENTRY(empty_bad_page)
- .space PAGE_SIZE
-
- .balign PAGE_SIZE
-ENTRY(empty_bad_pte_table)
- .space PAGE_SIZE
-
- .balign PAGE_SIZE
ENTRY(large_page_table)
.space PAGE_SIZE
diff --git a/arch/sh/kernel/head_64.S b/arch/sh/kernel/head_64.S
index defd851abefa..cca491397a28 100644
--- a/arch/sh/kernel/head_64.S
+++ b/arch/sh/kernel/head_64.S
@@ -101,14 +101,6 @@ empty_zero_page:
mmu_pdtp_cache:
.space PAGE_SIZE, 0
- .global empty_bad_page
-empty_bad_page:
- .space PAGE_SIZE, 0
-
- .global empty_bad_pte_table
-empty_bad_pte_table:
- .space PAGE_SIZE, 0
-
.global fpu_in_use
fpu_in_use: .quad 0
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index e7437ec62710..3c0e470ea646 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -22,8 +22,6 @@
/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
unsigned long *empty_zero_page = NULL;
EXPORT_SYMBOL(empty_zero_page);
-/* allocated in paging_init and unchanged thereafter */
-static unsigned long *empty_bad_page = NULL;
/*
* Initialized during boot, and readonly for initializing page tables
@@ -146,7 +144,6 @@ void __init paging_init(void)
int i;
empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
- empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
for (i = 0; i < ARRAY_SIZE(zones_size); i++)
zones_size[i] = 0;