From 031bc5743f158b2d5498294f489e534a31251626 Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Date: Fri, 12 Dec 2014 16:55:52 -0800
Subject: [PATCH] mm/debug-pagealloc: make debug-pagealloc boottime
configurable
Now, we have prepared to avoid using debug-pagealloc in boottime. So
introduce new kernel-parameter to disable debug-pagealloc in boottime, and
makes related functions to be disabled in this case.
Only non-intuitive part is change of guard page functions. Because guard
page is effective only if debug-pagealloc is enabled, turning off
according to debug-pagealloc is reasonable thing to do.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/kernel-parameters.txt | 9 +++++++++
arch/powerpc/mm/hash_utils_64.c | 2 +-
arch/powerpc/mm/pgtable_32.c | 2 +-
arch/s390/mm/pageattr.c | 2 +-
arch/sparc/mm/init_64.c | 2 +-
arch/x86/mm/pageattr.c | 2 +-
include/linux/mm.h | 17 ++++++++++++++++-
mm/debug-pagealloc.c | 8 +++++++-
mm/page_alloc.c | 20 ++++++++++++++++++++
9 files changed, 57 insertions(+), 7 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 24539d1c7d2504..6f067954675b90 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -829,6 +829,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
CONFIG_DEBUG_PAGEALLOC, hence this option will not help
tracking down these problems.
+ debug_pagealloc=
+ [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
+ parameter enables the feature at boot time. In
+ default, it is disabled. We can avoid allocating huge
+ chunk of memory for debug pagealloc if we don't enable
+ it at boot time and the system will work mostly same
+ with the kernel built without CONFIG_DEBUG_PAGEALLOC.
+ on: enable the feature
+
debugpat [X86] Enable PAT debugging
decnet.addr= [HW,NET]
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index e56a307bc676b3..2c2022d1605905 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1514,7 +1514,7 @@ static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
mmu_kernel_ssize, 0);
}
-void kernel_map_pages(struct page *page, int numpages, int enable)
+void __kernel_map_pages(struct page *page, int numpages, int enable)
{
unsigned long flags, vaddr, lmi;
int i;
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index d545b12315947c..50fad3801f3040 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -429,7 +429,7 @@ static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
}
-void kernel_map_pages(struct page *page, int numpages, int enable)
+void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
return;
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c
index 3fef3b29966579..426c9d462d1ce3 100644
--- a/arch/s390/mm/pageattr.c
+++ b/arch/s390/mm/pageattr.c
@@ -120,7 +120,7 @@ static void ipte_range(pte_t *pte, unsigned long address, int nr)
}
}
-void kernel_map_pages(struct page *page, int numpages, int enable)
+void __kernel_map_pages(struct page *page, int numpages, int enable)
{
unsigned long address;
int nr, i, j;
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 2d91c62f7f5f15..3ea267c53320d4 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -1621,7 +1621,7 @@ static void __init kernel_physical_mapping_init(void)
}
#ifdef CONFIG_DEBUG_PAGEALLOC
-void kernel_map_pages(struct page *page, int numpages, int enable)
+void __kernel_map_pages(struct page *page, int numpages, int enable)
{
unsigned long phys_start = page_to_pfn(page) << PAGE_SHIFT;
unsigned long phys_end = phys_start + (numpages * PAGE_SIZE);
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index a3a5d46605d299..dfaf2e0f5f8fc5 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1817,7 +1817,7 @@ static int __set_pages_np(struct page *page, int numpages)
return __change_page_attr_set_clr(&cpa, 0);
}
-void kernel_map_pages(struct page *page, int numpages, int enable)
+void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
return;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 66560f1a056498..8b8d77a1532f9a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2061,7 +2061,22 @@ static inline void vm_stat_account(struct mm_struct *mm,
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_DEBUG_PAGEALLOC
-extern void kernel_map_pages(struct page *page, int numpages, int enable);
+extern bool _debug_pagealloc_enabled;
+extern void __kernel_map_pages(struct page *page, int numpages, int enable);
+
+static inline bool debug_pagealloc_enabled(void)
+{
+ return _debug_pagealloc_enabled;
+}
+
+static inline void
+kernel_map_pages(struct page *page, int numpages, int enable)
+{
+ if (!debug_pagealloc_enabled())
+ return;
+
+ __kernel_map_pages(page, numpages, enable);
+}
#ifdef CONFIG_HIBERNATION
extern bool kernel_page_present(struct page *page);
#endif /* CONFIG_HIBERNATION */
diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
index 0072f2c533313f..5bf5906ce13b73 100644
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -10,11 +10,17 @@ static bool page_poisoning_enabled __read_mostly;
static bool need_page_poisoning(void)
{
+ if (!debug_pagealloc_enabled())
+ return false;
+
return true;
}
static void init_page_poisoning(void)
{
+ if (!debug_pagealloc_enabled())
+ return;
+
page_poisoning_enabled = true;
}
@@ -119,7 +125,7 @@ static void unpoison_pages(struct page *page, int n)
unpoison_page(page + i);
}
-void kernel_map_pages(struct page *page, int numpages, int enable)
+void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (!page_poisoning_enabled)
return;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e0a39d328ca188..303d385168076d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -425,15 +425,35 @@ static inline void prep_zero_page(struct page *page, unsigned int order,
#ifdef CONFIG_DEBUG_PAGEALLOC
unsigned int _debug_guardpage_minorder;
+bool _debug_pagealloc_enabled __read_mostly;
bool _debug_guardpage_enabled __read_mostly;
+static int __init early_debug_pagealloc(char *buf)
+{
+ if (!buf)
+ return -EINVAL;
+
+ if (strcmp(buf, "on") == 0)
+ _debug_pagealloc_enabled = true;
+
+ return 0;
+}
+early_param("debug_pagealloc", early_debug_pagealloc);
+
static bool need_debug_guardpage(void)
{
+ /* If we don't use debug_pagealloc, we don't need guard page */
+ if (!debug_pagealloc_enabled())
+ return false;
+
return true;
}
static void init_debug_guardpage(void)
{
+ if (!debug_pagealloc_enabled())
+ return;
+
_debug_guardpage_enabled = true;
}
--
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