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Date: Sat, 9 Jun 2012 14:29:49 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: linux-mm@...ck.org, kamezawa.hiroyu@...fujitsu.com,
dhillf@...il.com, rientjes@...gle.com, mhocko@...e.cz,
akpm@...ux-foundation.org, hannes@...xchg.org
Cc: linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH -V8 04/16] hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Use an mmu_gather instead of a temporary linked list for accumulating
pages when we unmap a hugepage range. This also allows us to get rid of
i_mmap_mutex unmap_hugepage_range in the following patch.
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
fs/hugetlbfs/inode.c | 4 ++--
include/linux/hugetlb.h | 22 ++++++++++++++----
mm/hugetlb.c | 59 ++++++++++++++++++++++++++++-------------------
mm/memory.c | 7 ++++--
4 files changed, 59 insertions(+), 33 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index cc9281b..ff233e4 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -416,8 +416,8 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
else
v_offset = 0;
- __unmap_hugepage_range(vma,
- vma->vm_start + v_offset, vma->vm_end, NULL);
+ unmap_hugepage_range(vma, vma->vm_start + v_offset,
+ vma->vm_end, NULL);
}
}
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 217f528..0f23c18 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -7,6 +7,7 @@
struct ctl_table;
struct user_struct;
+struct mmu_gather;
#ifdef CONFIG_HUGETLB_PAGE
@@ -40,9 +41,10 @@ int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
struct page **, struct vm_area_struct **,
unsigned long *, int *, int, unsigned int flags);
void unmap_hugepage_range(struct vm_area_struct *,
- unsigned long, unsigned long, struct page *);
-void __unmap_hugepage_range(struct vm_area_struct *,
- unsigned long, unsigned long, struct page *);
+ unsigned long, unsigned long, struct page *);
+void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ struct page *ref_page);
int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
void hugetlb_report_meminfo(struct seq_file *);
int hugetlb_report_node_meminfo(int, char *);
@@ -98,7 +100,6 @@ static inline unsigned long hugetlb_total_pages(void)
#define follow_huge_addr(mm, addr, write) ERR_PTR(-EINVAL)
#define copy_hugetlb_page_range(src, dst, vma) ({ BUG(); 0; })
#define hugetlb_prefault(mapping, vma) ({ BUG(); 0; })
-#define unmap_hugepage_range(vma, start, end, page) BUG()
static inline void hugetlb_report_meminfo(struct seq_file *m)
{
}
@@ -112,13 +113,24 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
#define hugetlb_fault(mm, vma, addr, flags) ({ BUG(); 0; })
#define huge_pte_offset(mm, address) 0
-#define dequeue_hwpoisoned_huge_page(page) 0
+static inline int dequeue_hwpoisoned_huge_page(struct page *page)
+{
+ return 0;
+}
+
static inline void copy_huge_page(struct page *dst, struct page *src)
{
}
#define hugetlb_change_protection(vma, address, end, newprot)
+static inline void __unmap_hugepage_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, struct page *ref_page)
+{
+ BUG();
+}
+
#endif /* !CONFIG_HUGETLB_PAGE */
#define HUGETLB_ANON_FILE "anon_hugepage"
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b1e0ed1..e54b695 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -24,8 +24,9 @@
#include <asm/page.h>
#include <asm/pgtable.h>
-#include <linux/io.h>
+#include <asm/tlb.h>
+#include <linux/io.h>
#include <linux/hugetlb.h>
#include <linux/node.h>
#include "internal.h"
@@ -2310,30 +2311,26 @@ static int is_hugetlb_entry_hwpoisoned(pte_t pte)
return 0;
}
-void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end, struct page *ref_page)
+void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ struct page *ref_page)
{
+ int force_flush = 0;
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *ptep;
pte_t pte;
struct page *page;
- struct page *tmp;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
- /*
- * A page gathering list, protected by per file i_mmap_mutex. The
- * lock is used to avoid list corruption from multiple unmapping
- * of the same page since we are using page->lru.
- */
- LIST_HEAD(page_list);
-
WARN_ON(!is_vm_hugetlb_page(vma));
BUG_ON(start & ~huge_page_mask(h));
BUG_ON(end & ~huge_page_mask(h));
+ tlb_start_vma(tlb, vma);
mmu_notifier_invalidate_range_start(mm, start, end);
+again:
spin_lock(&mm->page_table_lock);
for (address = start; address < end; address += sz) {
ptep = huge_pte_offset(mm, address);
@@ -2372,30 +2369,45 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
}
pte = huge_ptep_get_and_clear(mm, address, ptep);
+ tlb_remove_tlb_entry(tlb, ptep, address);
if (pte_dirty(pte))
set_page_dirty(page);
- list_add(&page->lru, &page_list);
+ page_remove_rmap(page);
+ force_flush = !__tlb_remove_page(tlb, page);
+ if (force_flush)
+ break;
/* Bail out after unmapping reference page if supplied */
if (ref_page)
break;
}
- flush_tlb_range(vma, start, end);
spin_unlock(&mm->page_table_lock);
- mmu_notifier_invalidate_range_end(mm, start, end);
- list_for_each_entry_safe(page, tmp, &page_list, lru) {
- page_remove_rmap(page);
- list_del(&page->lru);
- put_page(page);
+ /*
+ * mmu_gather ran out of room to batch pages, we break out of
+ * the PTE lock to avoid doing the potential expensive TLB invalidate
+ * and page-free while holding it.
+ */
+ if (force_flush) {
+ force_flush = 0;
+ tlb_flush_mmu(tlb);
+ if (address < end && !ref_page)
+ goto again;
}
+ mmu_notifier_invalidate_range_end(mm, start, end);
+ tlb_end_vma(tlb, vma);
}
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end, struct page *ref_page)
{
- mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
- __unmap_hugepage_range(vma, start, end, ref_page);
- mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ struct mm_struct *mm;
+ struct mmu_gather tlb;
+
+ mm = vma->vm_mm;
+
+ tlb_gather_mmu(&tlb, mm, 0);
+ __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
+ tlb_finish_mmu(&tlb, start, end);
}
/*
@@ -2440,9 +2452,8 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
* from the time of fork. This would look like data corruption
*/
if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
- __unmap_hugepage_range(iter_vma,
- address, address + huge_page_size(h),
- page);
+ unmap_hugepage_range(iter_vma, address,
+ address + huge_page_size(h), page);
}
mutex_unlock(&mapping->i_mmap_mutex);
diff --git a/mm/memory.c b/mm/memory.c
index 1b7dc66..545e18a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1326,8 +1326,11 @@ static void unmap_single_vma(struct mmu_gather *tlb,
* Since no pte has actually been setup, it is
* safe to do nothing in this case.
*/
- if (vma->vm_file)
- unmap_hugepage_range(vma, start, end, NULL);
+ if (vma->vm_file) {
+ mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ __unmap_hugepage_range(tlb, vma, start, end, NULL);
+ mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ }
} else
unmap_page_range(tlb, vma, start, end, details);
}
--
1.7.10
--
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