Re: [PATCH v2 12/13] rwsem: do not block readers at head of queue if other readers are active

2013-03-28 Thread Peter Hurley
On Fri, 2013-03-15 at 03:54 -0700, Michel Lespinasse wrote: > This change fixes a race condition where a reader might determine it > needs to block, but by the time it acquires the wait_lock the rwsem > has active readers and no queued waiters. > > In this situation the reader can just in

Re: [PATCH v2 12/13] rwsem: do not block readers at head of queue if other readers are active

2013-03-28 Thread Peter Hurley
On Fri, 2013-03-15 at 03:54 -0700, Michel Lespinasse wrote: This change fixes a race condition where a reader might determine it needs to block, but by the time it acquires the wait_lock the rwsem has active readers and no queued waiters. In this situation the reader can just in parallel

[PATCH v2 12/13] rwsem: do not block readers at head of queue if other readers are active

2013-03-15 Thread Michel Lespinasse
This change fixes a race condition where a reader might determine it needs to block, but by the time it acquires the wait_lock the rwsem has active readers and no queued waiters. In this situation the reader can just in parallel with the existing active readers; it does not need to block until

[PATCH v2 12/13] rwsem: do not block readers at head of queue if other readers are active

2013-03-15 Thread Michel Lespinasse
This change fixes a race condition where a reader might determine it needs to block, but by the time it acquires the wait_lock the rwsem has active readers and no queued waiters. In this situation the reader can just in parallel with the existing active readers; it does not need to block until