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authorJens Axboe <axboe@suse.de>2006-06-13 02:26:10 -0400
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-06-23 11:10:39 -0400
commitb31dc66a54ad986b6b73bdc49c8efc17cbad1833 (patch)
tree5591383c1cbffe11512da889c971f899333f1a44 /mm
parent271f18f102c789f59644bb6c53a69da1df72b2f4 (diff)
[PATCH] Kill PF_SYNCWRITE flag
A process flag to indicate whether we are doing sync io is incredibly ugly. It also causes performance problems when one does a lot of async io and then proceeds to sync it. Part of the io will go out as async, and the other part as sync. This causes a disconnect between the previously submitted io and the synced io. For io schedulers such as CFQ, this will cause us lost merges and suboptimal behaviour in scheduling. Remove PF_SYNCWRITE completely from the fsync/msync paths, and let the O_DIRECT path just directly indicate that the writes are sync by using WRITE_SYNC instead. Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'mm')
-rw-r--r--mm/msync.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/mm/msync.c b/mm/msync.c
index bc6c95376366..d083544df21b 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -170,8 +170,6 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
170 * just ignore them, but return -ENOMEM at the end. 170 * just ignore them, but return -ENOMEM at the end.
171 */ 171 */
172 down_read(&current->mm->mmap_sem); 172 down_read(&current->mm->mmap_sem);
173 if (flags & MS_SYNC)
174 current->flags |= PF_SYNCWRITE;
175 vma = find_vma(current->mm, start); 173 vma = find_vma(current->mm, start);
176 if (!vma) { 174 if (!vma) {
177 error = -ENOMEM; 175 error = -ENOMEM;
@@ -228,7 +226,6 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
228 } 226 }
229 } while (vma && !done); 227 } while (vma && !done);
230out_unlock: 228out_unlock:
231 current->flags &= ~PF_SYNCWRITE;
232 up_read(&current->mm->mmap_sem); 229 up_read(&current->mm->mmap_sem);
233out: 230out:
234 return error; 231 return error;