mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-10-31 18:09:19 +00:00
thp: introduce sysfs knob to disable huge zero page
By default kernel tries to use huge zero page on read page fault. It's possible to disable huge zero page by writing 0 or enable it back by writing 1: echo 0 >/sys/kernel/mm/transparent_hugepage/khugepaged/use_zero_page echo 1 >/sys/kernel/mm/transparent_hugepage/khugepaged/use_zero_page Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: "H. Peter Anvin" <hpa@linux.intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
d8a8e1f0da
commit
79da5407ee
3 changed files with 30 additions and 2 deletions
|
@ -116,6 +116,13 @@ echo always >/sys/kernel/mm/transparent_hugepage/defrag
|
|||
echo madvise >/sys/kernel/mm/transparent_hugepage/defrag
|
||||
echo never >/sys/kernel/mm/transparent_hugepage/defrag
|
||||
|
||||
By default kernel tries to use huge zero page on read page fault.
|
||||
It's possible to disable huge zero page by writing 0 or enable it
|
||||
back by writing 1:
|
||||
|
||||
echo 0 >/sys/kernel/mm/transparent_hugepage/khugepaged/use_zero_page
|
||||
echo 1 >/sys/kernel/mm/transparent_hugepage/khugepaged/use_zero_page
|
||||
|
||||
khugepaged will be automatically started when
|
||||
transparent_hugepage/enabled is set to "always" or "madvise, and it'll
|
||||
be automatically shutdown if it's set to "never".
|
||||
|
|
|
@ -39,6 +39,7 @@ enum transparent_hugepage_flag {
|
|||
TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
|
||||
TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
|
||||
TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG,
|
||||
TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG,
|
||||
#ifdef CONFIG_DEBUG_VM
|
||||
TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG,
|
||||
#endif
|
||||
|
@ -78,6 +79,9 @@ extern bool is_vma_temporary_stack(struct vm_area_struct *vma);
|
|||
(transparent_hugepage_flags & \
|
||||
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG) && \
|
||||
(__vma)->vm_flags & VM_HUGEPAGE))
|
||||
#define transparent_hugepage_use_zero_page() \
|
||||
(transparent_hugepage_flags & \
|
||||
(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG))
|
||||
#ifdef CONFIG_DEBUG_VM
|
||||
#define transparent_hugepage_debug_cow() \
|
||||
(transparent_hugepage_flags & \
|
||||
|
|
|
@ -39,7 +39,8 @@ unsigned long transparent_hugepage_flags __read_mostly =
|
|||
(1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
|
||||
#endif
|
||||
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
|
||||
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
|
||||
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
|
||||
(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
|
||||
|
||||
/* default scan 8*512 pte (or vmas) every 30 second */
|
||||
static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8;
|
||||
|
@ -357,6 +358,20 @@ static ssize_t defrag_store(struct kobject *kobj,
|
|||
static struct kobj_attribute defrag_attr =
|
||||
__ATTR(defrag, 0644, defrag_show, defrag_store);
|
||||
|
||||
static ssize_t use_zero_page_show(struct kobject *kobj,
|
||||
struct kobj_attribute *attr, char *buf)
|
||||
{
|
||||
return single_flag_show(kobj, attr, buf,
|
||||
TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
|
||||
}
|
||||
static ssize_t use_zero_page_store(struct kobject *kobj,
|
||||
struct kobj_attribute *attr, const char *buf, size_t count)
|
||||
{
|
||||
return single_flag_store(kobj, attr, buf, count,
|
||||
TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
|
||||
}
|
||||
static struct kobj_attribute use_zero_page_attr =
|
||||
__ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
|
||||
#ifdef CONFIG_DEBUG_VM
|
||||
static ssize_t debug_cow_show(struct kobject *kobj,
|
||||
struct kobj_attribute *attr, char *buf)
|
||||
|
@ -378,6 +393,7 @@ static struct kobj_attribute debug_cow_attr =
|
|||
static struct attribute *hugepage_attr[] = {
|
||||
&enabled_attr.attr,
|
||||
&defrag_attr.attr,
|
||||
&use_zero_page_attr.attr,
|
||||
#ifdef CONFIG_DEBUG_VM
|
||||
&debug_cow_attr.attr,
|
||||
#endif
|
||||
|
@ -779,7 +795,8 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|||
return VM_FAULT_OOM;
|
||||
if (unlikely(khugepaged_enter(vma)))
|
||||
return VM_FAULT_OOM;
|
||||
if (!(flags & FAULT_FLAG_WRITE)) {
|
||||
if (!(flags & FAULT_FLAG_WRITE) &&
|
||||
transparent_hugepage_use_zero_page()) {
|
||||
pgtable_t pgtable;
|
||||
unsigned long zero_pfn;
|
||||
pgtable = pte_alloc_one(mm, haddr);
|
||||
|
|
Loading…
Reference in a new issue