The patch titled
page_fault-retry-with-nopage_retry-fix 3
has been removed from the -mm tree. Its filename was
page_fault-retry-with-nopage_retry-fix-3.patch
This patch was dropped because it was folded into page_fault-retry-with-nopage_retry.patch
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: page_fault-retry-with-nopage_retry-fix 3
From: Ying Han <yinghan@xxxxxxxxxx>
I found out that the flags was set as FAULT_FLAG_WRITE no matter
what(write/read) whence FAULT_FLAG_RETRY is set. the new patch changed
the logic which only set the flag in the "write" case.
Cc: Mike Waychison <mikew@xxxxxxxxxx>
Cc: Ying Han <yinghan@xxxxxxxxxx>
Cc: Török Edwin <edwintorok@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Rohit Seth <rohitseth@xxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Tested-by: Valdis.Kletnieks@xxxxxx
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/mm/fault.c | 6 ++++++
include/linux/mm.h | 4 ++--
include/linux/pagemap.h | 3 ---
mm/filemap.c | 8 ++++----
mm/memory.c | 5 +++--
5 files changed, 15 insertions(+), 11 deletions(-)
diff -puN arch/x86/mm/fault.c~page_fault-retry-with-nopage_retry-fix-3 arch/x86/mm/fault.c
--- a/arch/x86/mm/fault.c~page_fault-retry-with-nopage_retry-fix-3
+++ a/arch/x86/mm/fault.c
@@ -962,6 +962,12 @@ good_area:
return;
}
+ /*
+ * Here we retry fault once and switch to synchronous mode. The
+ * main reason is to prevent us from the cases of starvation.
+ * The retry logic open a starvation hole in which case pages might
+ * be removed or changed after the retry.
+ */
if (fault & VM_FAULT_RETRY) {
if (write & FAULT_FLAG_RETRY) {
retry_flag &= ~FAULT_FLAG_RETRY;
diff -puN include/linux/mm.h~page_fault-retry-with-nopage_retry-fix-3 include/linux/mm.h
--- a/include/linux/mm.h~page_fault-retry-with-nopage_retry-fix-3
+++ a/include/linux/mm.h
@@ -134,7 +134,7 @@ extern pgprot_t protection_map[16];
#define FAULT_FLAG_WRITE 0x01 /* Fault was a write access */
#define FAULT_FLAG_NONLINEAR 0x02 /* Fault was via a nonlinear mapping */
-#define FAULT_FLAG_RETRY 0x04 /* Retry majoy fault */
+#define FAULT_FLAG_RETRY 0x04 /* Retry major fault */
/*
* This interface is used by x86 PAT code to identify a pfn mapping that is
@@ -697,11 +697,11 @@ static inline int page_mapped(struct pag
#define VM_FAULT_MINOR 0 /* For backwards compat. Remove me quickly. */
+#define VM_FAULT_RETRY 0x0010
#define VM_FAULT_OOM 0x0001
#define VM_FAULT_SIGBUS 0x0002
#define VM_FAULT_MAJOR 0x0004
#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
-#define VM_FAULT_RETRY 0x0010
#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */
#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */
diff -puN include/linux/pagemap.h~page_fault-retry-with-nopage_retry-fix-3 include/linux/pagemap.h
--- a/include/linux/pagemap.h~page_fault-retry-with-nopage_retry-fix-3
+++ a/include/linux/pagemap.h
@@ -232,9 +232,6 @@ extern struct page * find_get_page(struc
pgoff_t index);
extern struct page * find_lock_page(struct address_space *mapping,
pgoff_t index);
-extern unsigned find_lock_page_retry(struct address_space *mapping,
- pgoff_t offset, struct vm_area_struct *vma,
- struct page **ppage, int retry);
extern struct page * find_or_create_page(struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask);
unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
diff -puN mm/filemap.c~page_fault-retry-with-nopage_retry-fix-3 mm/filemap.c
--- a/mm/filemap.c~page_fault-retry-with-nopage_retry-fix-3
+++ a/mm/filemap.c
@@ -764,15 +764,15 @@ EXPORT_SYMBOL(find_lock_page);
* @mapping: the address_space to search
* @offset: the page index
* @vma: vma in which the fault was taken
- * @ppage: zero if page not present, otherwise point to the page in pagecache.
+ * @ppage: zero if page not present, otherwise point to the page in pagecache
* @retry: 1 indicate caller tolerate a retry.
*
- * If retry flag is on, and page is already locked by someone else, return a
- * hint of retry.
+ * If retry flag is on, and page is already locked by someone else, return
+ * a hint of retry.
*
* Return *ppage==NULL if page is not in pagecache. Otherwise return *ppage
* points to the page in the pagecache with ret=VM_FAULT_RETRY indicate a
- * hint to caller for retry, or ret=0 which means page is successfully
+ * hint to caller for retry, or ret=0 which means page is succefully
* locked.
*/
unsigned find_lock_page_retry(struct address_space *mapping, pgoff_t offset,
diff -puN mm/memory.c~page_fault-retry-with-nopage_retry-fix-3 mm/memory.c
--- a/mm/memory.c~page_fault-retry-with-nopage_retry-fix-3
+++ a/mm/memory.c
@@ -2597,7 +2597,7 @@ static int __do_fault(struct mm_struct *
/* page may be available, but we have to restart the process
* because mmap_sem was dropped during the ->fault
*/
- if (ret == VM_FAULT_RETRY)
+ if (ret & VM_FAULT_RETRY)
return ret;
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
@@ -2741,7 +2741,8 @@ static int do_linear_fault(struct mm_str
{
pgoff_t pgoff = (((address & PAGE_MASK)
- vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
+ int write = write_access & ~FAULT_FLAG_RETRY;
+ unsigned int flags = (write ? FAULT_FLAG_WRITE : 0);
flags |= (write_access & FAULT_FLAG_RETRY);
pte_unmap(page_table);
_
Patches currently in -mm which might be from yinghan@xxxxxxxxxx are
page_fault-retry-with-nopage_retry.patch
page_fault-retry-with-nopage_retry-fix-3.patch
page_fault-retry-with-nopage_retry-fix-3-fix.patch
proc-pid-maps-dont-show-pgoff-of-pure-anon-vmas.patch
proc-pid-maps-dont-show-pgoff-of-pure-anon-vmas-checkpatch-fixes.patch
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