From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
For now, TRANSPARENT_HUGEPAGE_PAGECACHE is only implemented for X86_64.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 7 +++++++
mm/Kconfig | 10 ++++++++++
mm/huge_memory.c | 19 +++++++++++++++++++
3 files changed, 36 insertions(+)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 6b4c9b2..88b44e2 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -40,6 +40,7 @@ enum transparent_hugepage_flag {
TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG,
+ TRANSPARENT_HUGEPAGE_PAGECACHE,
TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG,
#ifdef CONFIG_DEBUG_VM
TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG,
@@ -240,4 +241,10 @@ static inline int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_str
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+static inline bool transparent_hugepage_pagecache(void)
+{
+ if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE_PAGECACHE))
+ return 0;
+ return transparent_hugepage_flags & (1<<TRANSPARENT_HUGEPAGE_PAGECACHE);
+}
#endif /* _LINUX_HUGE_MM_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index e742d06..3a271b7 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -420,6 +420,16 @@ choice
benefit.
endchoice
+config TRANSPARENT_HUGEPAGE_PAGECACHE
+ bool "Transparent Hugepage Support for page cache"
+ depends on X86_64 && TRANSPARENT_HUGEPAGE
+ default y
+ help
+ Enabling the option adds support hugepages for file-backed
+ mappings. It requires transparent hugepage support from
+ filesystem side. For now, the only filesystem which supports
+ hugepages is ramfs.
+
config CROSS_MEMORY_ATTACH
bool "Cross Memory Support"
depends on MMU
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b39fa01..bd8ef7f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -42,6 +42,9 @@ unsigned long transparent_hugepage_flags __read_mostly =
#endif
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE_PAGECACHE
+ (1<<TRANSPARENT_HUGEPAGE_PAGECACHE)|
+#endif
(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
/* default scan 8*512 pte (or vmas) every 30 second */
@@ -357,6 +360,21 @@ static ssize_t defrag_store(struct kobject *kobj,
static struct kobj_attribute defrag_attr =
__ATTR(defrag, 0644, defrag_show, defrag_store);
+static ssize_t page_cache_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return single_flag_show(kobj, attr, buf,
+ TRANSPARENT_HUGEPAGE_PAGECACHE);
+}
+static ssize_t page_cache_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ return single_flag_store(kobj, attr, buf, count,
+ TRANSPARENT_HUGEPAGE_PAGECACHE);
+}
+static struct kobj_attribute page_cache_attr =
+ __ATTR(page_cache, 0644, page_cache_show, page_cache_store);
+
static ssize_t use_zero_page_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
@@ -392,6 +410,7 @@ static struct kobj_attribute debug_cow_attr =
static struct attribute *hugepage_attr[] = {
&enabled_attr.attr,
&defrag_attr.attr,
+ &page_cache_attr.attr,
&use_zero_page_attr.attr,
#ifdef CONFIG_DEBUG_VM
&debug_cow_attr.attr,
--
1.7.10.4
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