Re: [PATCH] sunrpc/nfs: don't allow TASK_KILLABLE sleeps to block the freezer
From: Rafael J. Wysocki
Date: Thu Dec 01 2011 - 16:49:20 EST
On Thursday, December 01, 2011, Jeff Layton wrote:
> Allow the freezer to skip wait_on_bit_killable sleeps in the sunrpc
> layer. This should allow suspend and hibernate events to proceed, even
> when there are RPC's pending on the wire.
>
> Also, wrap the TASK_KILLABLE sleeps in NFS layer in freezer_do_not_count
> and freezer_count calls. This allows the freezer to skip tasks that are
> sleeping while looping on EJUKEBOX or NFS4ERR_DELAY sorts of errors.
>
> Rafael, I've gone ahead and combined the two patches into one here
> and rebased this on top of the pm-freezer branch. Let me know if you'd
> prefer to keep it as two patches.
One patch is just fine for me, applied to linux-pm/linux-next.
Thanks,
Rafael
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/nfs/inode.c | 3 ++-
> fs/nfs/nfs3proc.c | 3 ++-
> fs/nfs/nfs4proc.c | 5 +++--
> fs/nfs/proc.c | 3 ++-
> include/linux/freezer.h | 28 ++++++++++++++++++++++++++++
> net/sunrpc/sched.c | 3 ++-
> 6 files changed, 39 insertions(+), 6 deletions(-)
>
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 50a15fa..bf3a57b 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -38,6 +38,7 @@
> #include <linux/nfs_xdr.h>
> #include <linux/slab.h>
> #include <linux/compat.h>
> +#include <linux/freezer.h>
>
> #include <asm/system.h>
> #include <asm/uaccess.h>
> @@ -77,7 +78,7 @@ int nfs_wait_bit_killable(void *word)
> {
> if (fatal_signal_pending(current))
> return -ERESTARTSYS;
> - schedule();
> + freezable_schedule();
> return 0;
> }
>
> diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
> index d4bc9ed9..9194395 100644
> --- a/fs/nfs/nfs3proc.c
> +++ b/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"
> @@ -32,7 +33,7 @@ nfs3_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
> res = rpc_call_sync(clnt, msg, flags);
> if (res != -EJUKEBOX && res != -EKEYEXPIRED)
> break;
> - schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
> + freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
> res = -ERESTARTSYS;
> } while (!fatal_signal_pending(current));
> return res;
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index be2bbac..b28bb19 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -53,6 +53,7 @@
> #include <linux/sunrpc/bc_xprt.h>
> #include <linux/xattr.h>
> #include <linux/utsname.h>
> +#include <linux/freezer.h>
>
> #include "nfs4_fs.h"
> #include "delegation.h"
> @@ -241,7 +242,7 @@ static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
> *timeout = NFS4_POLL_RETRY_MIN;
> if (*timeout > NFS4_POLL_RETRY_MAX)
> *timeout = NFS4_POLL_RETRY_MAX;
> - schedule_timeout_killable(*timeout);
> + freezable_schedule_timeout_killable(*timeout);
> if (fatal_signal_pending(current))
> res = -ERESTARTSYS;
> *timeout <<= 1;
> @@ -3950,7 +3951,7 @@ int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4
> static unsigned long
> nfs4_set_lock_task_retry(unsigned long timeout)
> {
> - schedule_timeout_killable(timeout);
> + freezable_schedule_timeout_killable(timeout);
> timeout <<= 1;
> if (timeout > NFS4_LOCK_MAXTIMEOUT)
> return NFS4_LOCK_MAXTIMEOUT;
> diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
> index f48125d..0c672588 100644
> --- a/fs/nfs/proc.c
> +++ b/fs/nfs/proc.c
> @@ -41,6 +41,7 @@
> #include <linux/nfs_fs.h>
> #include <linux/nfs_page.h>
> #include <linux/lockd/bind.h>
> +#include <linux/freezer.h>
> #include "internal.h"
>
> #define NFSDBG_FACILITY NFSDBG_PROC
> @@ -59,7 +60,7 @@ nfs_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
> res = rpc_call_sync(clnt, msg, flags);
> if (res != -EKEYEXPIRED)
> break;
> - schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
> + freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
> res = -ERESTARTSYS;
> } while (!fatal_signal_pending(current));
> return res;
> diff --git a/include/linux/freezer.h b/include/linux/freezer.h
> index c1ee283..30f06c2 100644
> --- a/include/linux/freezer.h
> +++ b/include/linux/freezer.h
> @@ -105,6 +105,29 @@ static inline int freezer_should_skip(struct task_struct *p)
> }
>
> /*
> + * These macros are intended to be used whenever you want allow a task that's
> + * sleeping in TASK_UNINTERRUPTIBLE or TASK_KILLABLE state to be frozen. Note
> + * that neither return any clear indication of whether a freeze event happened
> + * while in this function.
> + */
> +
> +/* Like schedule(), but should not block the freezer. */
> +#define freezable_schedule() \
> +({ \
> + freezer_do_not_count(); \
> + schedule(); \
> + freezer_count(); \
> +})
> +
> +/* Like schedule_timeout_killable(), but should not block the freezer. */
> +#define freezable_schedule_timeout_killable(timeout) \
> +({ \
> + freezer_do_not_count(); \
> + schedule_timeout_killable(timeout); \
> + freezer_count(); \
> +})
> +
> +/*
> * Freezer-friendly wrappers around wait_event_interruptible(),
> * wait_event_killable() and wait_event_interruptible_timeout(), originally
> * defined in <linux/wait.h>
> @@ -163,6 +186,11 @@ static inline void freezer_count(void) {}
> static inline int freezer_should_skip(struct task_struct *p) { return 0; }
> static inline void set_freezable(void) {}
>
> +#define freezable_schedule() schedule()
> +
> +#define freezable_schedule_timeout_killable(timeout) \
> + schedule_timeout_killable(timeout)
> +
> #define wait_event_freezable(wq, condition) \
> wait_event_interruptible(wq, condition)
>
> diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> index d12ffa5..5317b93 100644
> --- a/net/sunrpc/sched.c
> +++ b/net/sunrpc/sched.c
> @@ -18,6 +18,7 @@
> #include <linux/smp.h>
> #include <linux/spinlock.h>
> #include <linux/mutex.h>
> +#include <linux/freezer.h>
>
> #include <linux/sunrpc/clnt.h>
>
> @@ -231,7 +232,7 @@ static int rpc_wait_bit_killable(void *word)
> {
> if (fatal_signal_pending(current))
> return -ERESTARTSYS;
> - schedule();
> + freezable_schedule();
> return 0;
> }
>
>
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