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authorJens Axboe <jens.axboe@oracle.com>2008-01-24 08:52:45 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-01-28 10:50:29 +0100
commitfd0928df98b9578be8a786ac0cb78a47a5e17a20 (patch)
tree70a34cf207bea1bec28e59cf0dba7d20e7f8b0f1 /fs/ioprio.c
parent91525300baf162e83e923b09ca286f9205e21522 (diff)
downloadlwn-fd0928df98b9578be8a786ac0cb78a47a5e17a20.tar.gz
lwn-fd0928df98b9578be8a786ac0cb78a47a5e17a20.zip
ioprio: move io priority from task_struct to io_context
This is where it belongs and then it doesn't take up space for a process that doesn't do IO. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs/ioprio.c')
-rw-r--r--fs/ioprio.c29
1 files changed, 21 insertions, 8 deletions
diff --git a/fs/ioprio.c b/fs/ioprio.c
index e4e01bc7f338..a7600401ecf7 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -41,18 +41,29 @@ static int set_task_ioprio(struct task_struct *task, int ioprio)
return err;
task_lock(task);
+ do {
+ ioc = task->io_context;
+ /* see wmb() in current_io_context() */
+ smp_read_barrier_depends();
+ if (ioc)
+ break;
- task->ioprio = ioprio;
-
- ioc = task->io_context;
- /* see wmb() in current_io_context() */
- smp_read_barrier_depends();
+ ioc = alloc_io_context(GFP_ATOMIC, -1);
+ if (!ioc) {
+ err = -ENOMEM;
+ break;
+ }
+ task->io_context = ioc;
+ ioc->task = task;
+ } while (1);
- if (ioc)
+ if (!err) {
+ ioc->ioprio = ioprio;
ioc->ioprio_changed = 1;
+ }
task_unlock(task);
- return 0;
+ return err;
}
asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
@@ -148,7 +159,9 @@ static int get_task_ioprio(struct task_struct *p)
ret = security_task_getioprio(p);
if (ret)
goto out;
- ret = p->ioprio;
+ ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM);
+ if (p->io_context)
+ ret = p->io_context->ioprio;
out:
return ret;
}