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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-14 09:55:35 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-04-21 16:19:29 -0700 |
| commit | 989a2979205dd34269382b357e6d4b4b6956b889 (patch) | |
| tree | 2f504e9f4d8d418dd8fb2d042b076c1318232360 /include | |
| parent | tcp: Mark v6 response packets as CHECKSUM_PARTIAL (diff) | |
| download | linux-dev-989a2979205dd34269382b357e6d4b4b6956b889.tar.xz linux-dev-989a2979205dd34269382b357e6d4b4b6956b889.zip | |
fasync: RCU and fine grained locking
kill_fasync() uses a central rwlock, candidate for RCU conversion, to
avoid cache line ping pongs on SMP.
fasync_remove_entry() and fasync_add_entry() can disable IRQS on a short
section instead during whole list scan.
Use a spinlock per fasync_struct to synchronize kill_fasync_rcu() and
fasync_{remove|add}_entry(). This spinlock is IRQ safe, so sock_fasync()
doesnt need its own implementation and can use fasync_helper(), to
reduce code size and complexity.
We can remove __kill_fasync() direct use in net/socket.c, and rename it
to kill_fasync_rcu().
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fs.h | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 39d57bc6cc71..018d382f6f92 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1280,10 +1280,12 @@ static inline int lock_may_write(struct inode *inode, loff_t start, struct fasync_struct { - int magic; - int fa_fd; - struct fasync_struct *fa_next; /* singly linked list */ - struct file *fa_file; + spinlock_t fa_lock; + int magic; + int fa_fd; + struct fasync_struct *fa_next; /* singly linked list */ + struct file *fa_file; + struct rcu_head fa_rcu; }; #define FASYNC_MAGIC 0x4601 @@ -1292,8 +1294,6 @@ struct fasync_struct { extern int fasync_helper(int, struct file *, int, struct fasync_struct **); /* can be called from interrupts */ extern void kill_fasync(struct fasync_struct **, int, int); -/* only for net: no internal synchronization */ -extern void __kill_fasync(struct fasync_struct *, int, int); extern int __f_setown(struct file *filp, struct pid *, enum pid_type, int force); extern int f_setown(struct file *filp, unsigned long arg, int force); |