On Fri, 2013-03-15 at 03:54 -0700, Michel Lespinasse wrote:
> These patches extend Alex Shi's work (which added write lock stealing
> on the rwsem slow path) in order to provide rwsem write lock stealing
> on the fast path (that is, without taking the rwsem's wait_lock).
Since none of Alex's original code will be in here with these patches
applied, you might as well add this:
diff --git a/lib/rwsem.c b/lib/rwsem.c
index 4e4c889..61f91ca 100644
--- a/lib/rwsem.c
+++ b/lib/rwsem.c
@@ -4,6 +4,7 @@
* Derived from arch/i386/kernel/semaphore.c
*
* Writer lock-stealing by Alex Shi <alex....@intel.com>
+ * and Michel Lespinasse <wal...@google.com>
*/
#include <linux/rwsem.h>
#include <linux/sched.h>
> Michel Lespinasse (13):
> rwsem: make the waiter type an enumeration rather than a bitmask
> rwsem: shorter spinlocked section in rwsem_down_failed_common()
> rwsem: move rwsem_down_failed_common code into
> rwsem_down_{read,write}_failed
> rwsem: simplify rwsem_down_read_failed
> rwsem: simplify rwsem_down_write_failed
> rwsem: more agressive lock stealing in rwsem_down_write_failed
> rwsem: use cmpxchg for trying to steal write lock
> rwsem: avoid taking wait_lock in rwsem_down_write_failed
> rwsem: skip initial trylock in rwsem_down_write_failed
> rwsem: simplify __rwsem_do_wake
> rwsem: implement support for write lock stealing on the fastpath
> rwsem: do not block readers at head of queue if other readers are active
> x86 rwsem: avoid taking slow path when stealing write lock
>
> arch/x86/include/asm/rwsem.h | 28 +++--
> lib/rwsem-spinlock.c | 40 +++-----
> lib/rwsem.c | 239
> +++++++++++++++++++++----------------------
> 3 files changed, 154 insertions(+), 153 deletions(-)
Because Michel asked:
Reviewed-by: Peter Hurley <pe...@hurleysoftware.com>
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