gru: change resource assignment for kernel threads

Change the way GRU resources are assigned for kernel threads.  GRU
contexts for kernel threads are now allocated on demand and can be stolen
by user processes when idle.  This allows MPI jobs to use ALL of the GRU
resources when the kernel is not using them.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 3 deletions

diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h
index 4ddb5b92acbb..1c85fdcf5d37 100644
--- a/drivers/misc/sgi-gru/grutables.h
+++ b/drivers/misc/sgi-gru/grutables.h
@@ -174,9 +174,12 @@ struct gru_stats_s {
         atomic_long_t assign_context;
         atomic_long_t assign_context_failed;
         atomic_long_t free_context;
-        atomic_long_t load_context;
-        atomic_long_t unload_context;
-        atomic_long_t steal_context;
+        atomic_long_t load_user_context;
+        atomic_long_t load_kernel_context;
+        atomic_long_t lock_kernel_context;
+        atomic_long_t unlock_kernel_context;
+        atomic_long_t steal_user_context;
+        atomic_long_t steal_kernel_context;
         atomic_long_t steal_context_failed;
         atomic_long_t nopfn;
         atomic_long_t break_cow;
@@ -454,6 +457,9 @@ struct gru_blade_state {
                                                            reserved cb */
         void                    *kernel_dsr;            /* First kernel
                                                            reserved DSR */
+        struct rw_semaphore     bs_kgts_sema;           /* lock for kgts */
+        struct gru_thread_state *bs_kgts;               /* GTS for kernel use */
+
         /* ---- the following are protected by the bs_lock spinlock ---- */
         spinlock_t              bs_lock;                /* lock used for
                                                            stealing contexts */
@@ -597,6 +603,11 @@ static inline void unlock_tgh_handle(struct gru_tlb_global_handle *tgh)
         __unlock_handle(tgh);
 }
 
+static inline int is_kernel_context(struct gru_thread_state *gts)
+{
+        return !gts->ts_mm;
+}
+
 /*-----------------------------------------------------------------------------
  * Function prototypes & externs
  */