The patch titled
Subject: powerpc/oprofile: reduce mmap_sem hold for exe_file
has been added to the -mm tree. Its filename is
powerpc-oprofile-reduce-mmap_sem-hold-for-exe_file.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/powerpc-oprofile-reduce-mmap_sem-hold-for-exe_file.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/powerpc-oprofile-reduce-mmap_sem-hold-for-exe_file.patch
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------------------------------------------------------
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Subject: powerpc/oprofile: reduce mmap_sem hold for exe_file
In the future mm->exe_file will be done without mmap_sem serialization,
thus isolate and reorganize the related code to make the transition
easier. Good users will, make use of the more standard get_mm_exe_file(),
requiring only holding the mmap_sem to read the value, and relying on
reference counting to make sure that the exe file won't dissappear
underneath us while getting the dcookie.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Robert Richter <rric@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/oprofile/cell/spu_task_sync.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff -puN arch/powerpc/oprofile/cell/spu_task_sync.c~powerpc-oprofile-reduce-mmap_sem-hold-for-exe_file arch/powerpc/oprofile/cell/spu_task_sync.c
--- a/arch/powerpc/oprofile/cell/spu_task_sync.c~powerpc-oprofile-reduce-mmap_sem-hold-for-exe_file
+++ a/arch/powerpc/oprofile/cell/spu_task_sync.c
@@ -22,6 +22,7 @@
#include <linux/kref.h>
#include <linux/mm.h>
#include <linux/fs.h>
+#include <linux/file.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/numa.h>
@@ -322,18 +323,20 @@ get_exec_dcookie_and_offset(struct spu *
unsigned long app_cookie = 0;
unsigned int my_offset = 0;
struct vm_area_struct *vma;
+ struct file *exe_file;
struct mm_struct *mm = spu->mm;
if (!mm)
goto out;
- down_read(&mm->mmap_sem);
-
- if (mm->exe_file) {
- app_cookie = fast_get_dcookie(&mm->exe_file->f_path);
- pr_debug("got dcookie for %pD\n", mm->exe_file);
+ exe_file = get_mm_exe_file(mm);
+ if (exe_file) {
+ app_cookie = fast_get_dcookie(&exe_file->f_path);
+ pr_debug("got dcookie for %pD\n", exe_file);
+ fput(exe_file);
}
+ down_read(&mm->mmap_sem);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (vma->vm_start > spu_ref || vma->vm_end <= spu_ref)
continue;
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
mm-hugetlb-close-race-when-setting-pagetail-for-gigantic-pages.patch
arc-do-not-export-symbols-in-troubleshootc.patch
linux-next.patch
tile-elf-reorganize-notify_exec.patch
oprofile-reduce-mmap_sem-hold-for-mm-exe_file.patch
powerpc-oprofile-reduce-mmap_sem-hold-for-exe_file.patch
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