summaryrefslogtreecommitdiffstats
path: root/include/linux/fs.h
diff options
context:
space:
mode:
authorDipankar Sarma <dipankar@in.ibm.com>2005-09-09 13:04:13 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-09 13:57:55 -0700
commitab2af1f5005069321c5d130f09cce577b03f43ef (patch)
tree73a70ba486f522cd9eeeef376ede2b5a1c1b473b /include/linux/fs.h
parent6e72ad2c581de121cc7e772469e2a8f6b1fd4379 (diff)
downloadop-kernel-dev-ab2af1f5005069321c5d130f09cce577b03f43ef.zip
op-kernel-dev-ab2af1f5005069321c5d130f09cce577b03f43ef.tar.gz
[PATCH] files: files struct with RCU
Patch to eliminate struct files_struct.file_lock spinlock on the reader side and use rcu refcounting rcuref_xxx api for the f_count refcounter. The updates to the fdtable are done by allocating a new fdtable structure and setting files->fdt to point to the new structure. The fdtable structure is protected by RCU thereby allowing lock-free lookup. For fd arrays/sets that are vmalloced, we use keventd to free them since RCU callbacks can't sleep. A global list of fdtable to be freed is not scalable, so we use a per-cpu list. If keventd is already handling the current cpu's work, we use a timer to defer queueing of that work. Since the last publication, this patch has been re-written to avoid using explicit memory barriers and use rcu_assign_pointer(), rcu_dereference() premitives instead. This required that the fd information is kept in a separate structure (fdtable) and updated atomically. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r--include/linux/fs.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fd93ab7..7f61227 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -9,6 +9,7 @@
#include <linux/config.h>
#include <linux/limits.h>
#include <linux/ioctl.h>
+#include <linux/rcuref.h>
/*
* It's silly to have NR_OPEN bigger than NR_FILE, but you can change
@@ -597,12 +598,13 @@ struct file {
spinlock_t f_ep_lock;
#endif /* #ifdef CONFIG_EPOLL */
struct address_space *f_mapping;
+ struct rcu_head f_rcuhead;
};
extern spinlock_t files_lock;
#define file_list_lock() spin_lock(&files_lock);
#define file_list_unlock() spin_unlock(&files_lock);
-#define get_file(x) atomic_inc(&(x)->f_count)
+#define get_file(x) rcuref_inc(&(x)->f_count)
#define file_count(x) atomic_read(&(x)->f_count)
#define MAX_NON_LFS ((1UL<<31) - 1)
OpenPOWER on IntegriCloud