On Wed 2008-05-07 00:07:55, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> The introduction of TASK_KILLABLE allows the freezer to work in some situation
> that it could not handle before.
>
> Make the freezer handle killable tasks and add try_to_freeze() in some places
> where it is safe to freeze a (killable) task. Introduce the
> wait_event_killable_freezable() macro to be used wherever the freezing of
> a waiting killable task is desirable.
>
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> ---
> fs/nfs/inode.c | 2 ++
> fs/nfs/nfs3proc.c | 2 ++
> fs/nfs/nfs4proc.c | 4 ++++
> fs/nfs/pagelist.c | 8 ++++++--
> fs/smbfs/request.c | 2 ++
> include/linux/freezer.h | 20 +++++++++++++++++---
> kernel/mutex.c | 3 +++
> kernel/power/process.c | 6 ++++--
> kernel/sched.c | 2 ++
> net/sunrpc/sched.c | 2 ++
> 10 files changed, 44 insertions(+), 7 deletions(-)
>
> Index: linux-2.6/fs/nfs/nfs3proc.c
> ===================================================================
> --- linux-2.6.orig/fs/nfs/nfs3proc.c
> +++ linux-2.6/fs/nfs/nfs3proc.c
> @@ -17,6 +17,7 @@
> #include <linux/nfs_page.h>
> #include <linux/lockd/bind.h>
> #include <linux/nfs_mount.h>
> +#include <linux/freezer.h>
>
> #include "iostat.h"
> #include "internal.h"
> @@ -33,6 +34,7 @@ nfs3_rpc_wrapper(struct rpc_clnt *clnt,
> if (res != -EJUKEBOX)
> break;
> schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
> + try_to_freeze();
> res = -ERESTARTSYS;
> } while (!fatal_signal_pending(current));
> return res;
> Index: linux-2.6/fs/nfs/nfs4proc.c
> ===================================================================
> --- linux-2.6.orig/fs/nfs/nfs4proc.c
> +++ linux-2.6/fs/nfs/nfs4proc.c
> @@ -48,6 +48,7 @@
> #include <linux/smp_lock.h>
> #include <linux/namei.h>
> #include <linux/mount.h>
> +#include <linux/freezer.h>
>
> #include "nfs4_fs.h"
> #include "delegation.h"
> @@ -2788,6 +2789,7 @@ static int nfs4_wait_bit_killable(void *
> if (fatal_signal_pending(current))
> return -ERESTARTSYS;
> schedule();
> + try_to_freeze();
> return 0;
> }
I'd say try_to_freeze() belongs close to the other signal check,
i.e. before schedule?
> @@ -180,10 +182,12 @@ static int nfs_wait_bit_killable(void *w
> {
> int ret = 0;
>
> - if (fatal_signal_pending(current))
> + if (fatal_signal_pending(current)) {
> ret = -ERESTARTSYS;
> - else
> + } else {
> schedule();
> + try_to_freeze();
> + }
Same here?
> @@ -109,6 +110,7 @@ struct smb_request *smb_alloc_request(st
> return ERR_PTR(-ERESTARTSYS);
> current->policy = SCHED_YIELD;
> schedule();
> + try_to_freeze();
And here?
> @@ -182,6 +183,8 @@ __mutex_lock_common(struct mutex *lock,
> /* didnt get the lock, go to sleep: */
> spin_unlock_mutex(&lock->wait_lock, flags);
> schedule();
> + if (state == TASK_KILLABLE)
> + try_to_freeze();
> spin_lock_mutex(&lock->wait_lock, flags);
> }
>
I'm not comfortable with this one. Can the task be killable, but still
hold some _other_ mutex? (and then release it only if it actually gets
the signal?)
> Index: linux-2.6/kernel/sched.c
> ===================================================================
> --- linux-2.6.orig/kernel/sched.c
> +++ linux-2.6/kernel/sched.c
> @@ -4769,6 +4769,8 @@ do_wait_for_common(struct completion *x,
> __set_current_state(state);
> spin_unlock_irq(&x->wait.lock);
> timeout = schedule_timeout(timeout);
> + if (state == TASK_KILLABLE)
> + try_to_freeze();
> spin_lock_irq(&x->wait.lock);
> if (!timeout) {
> __remove_wait_queue(&x->wait, &wait);
Same here. I can't see why we could not be holding mutexes.
> @@ -227,6 +228,7 @@ static int rpc_wait_bit_killable(void *w
> if (fatal_signal_pending(current))
> return -ERESTARTSYS;
> schedule();
> + try_to_freeze();
> return 0;
> }
Swap?
> @@ -426,6 +427,7 @@ static int nfs_wait_schedule(void *word)
> if (signal_pending(current))
> return -ERESTARTSYS;
> schedule();
> + try_to_freeze();
> return 0;
> }
>
Swap?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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