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| author | Arnd Bergmann <arnd@arndb.de> | 2010-09-18 15:09:31 +0200 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2010-10-05 11:02:04 +0200 |
| commit | b89f432133851a01c0d28822f11cbdcc15781a75 (patch) | |
| tree | a3e9ba638a9b746985148f4525335d360ec7da56 /include/linux/fs.h | |
| parent | 2e54eb96e2c801f33d95b5dade15212ac4d6c4a5 (diff) | |
| download | lwn-b89f432133851a01c0d28822f11cbdcc15781a75.tar.gz lwn-b89f432133851a01c0d28822f11cbdcc15781a75.zip | |
fs/locks.c: prepare for BKL removal
This prepares the removal of the big kernel lock from the
file locking code. We still use the BKL as long as fs/lockd
uses it and ceph might sleep, but we can flip the definition
to a private spinlock as soon as that's done.
All users outside of fs/lockd get converted to use
lock_flocks() instead of lock_kernel() where appropriate.
Based on an earlier patch to use a spinlock from Matthew
Wilcox, who has attempted this a few times before, the
earliest patch from over 10 years ago turned it into
a semaphore, which ended up being slower than the BKL
and was subsequently reverted.
Someone should do some serious performance testing when
this becomes a spinlock, since this has caused problems
before. Using a spinlock should be at least as good
as the BKL in theory, but who knows...
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Sage Weil <sage@newdream.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 63d069bd80b7..180325268237 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1093,10 +1093,6 @@ struct file_lock { #include <linux/fcntl.h> -/* temporary stubs for BKL removal */ -#define lock_flocks() lock_kernel() -#define unlock_flocks() unlock_kernel() - extern void send_sigio(struct fown_struct *fown, int fd, int band); #ifdef CONFIG_FILE_LOCKING @@ -1135,6 +1131,8 @@ extern int vfs_setlease(struct file *, long, struct file_lock **); extern int lease_modify(struct file_lock **, int); extern int lock_may_read(struct inode *, loff_t start, unsigned long count); extern int lock_may_write(struct inode *, loff_t start, unsigned long count); +extern void lock_flocks(void); +extern void unlock_flocks(void); #else /* !CONFIG_FILE_LOCKING */ static inline int fcntl_getlk(struct file *file, struct flock __user *user) { @@ -1277,6 +1275,14 @@ static inline int lock_may_write(struct inode *inode, loff_t start, return 1; } +static inline void lock_flocks(void) +{ +} + +static inline void unlock_flocks(void) +{ +} + #endif /* !CONFIG_FILE_LOCKING */ |