gru: dynamic allocation of kernel contexts

Change the interface to gru_alloc_gts() so that it can be used to allocate
GRU contexts for kernel threads.  Kernel threads do not have vdata
structures for the GRU contexts.  The GRU resource count are now passed
explicitly instead of inside the vdata structure.

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>

drivers/misc/sgi-gru/grumain.c

@@ -299,15 +299,13 @@ static struct gru_thread_state *gru_find_current_gts_nolock(struct gru_vma_data
 /*
  * Allocate a thread state structure.
  */
-static struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
-					      struct gru_vma_data *vdata,
-					      int tsid)
+struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
+		int cbr_au_count, int dsr_au_count, int options, int tsid)
 {
 	struct gru_thread_state *gts;
 	int bytes;
 
-	bytes = DSR_BYTES(vdata->vd_dsr_au_count) +
-				CBR_BYTES(vdata->vd_cbr_au_count);
+	bytes = DSR_BYTES(dsr_au_count) + CBR_BYTES(cbr_au_count);
 	bytes += sizeof(struct gru_thread_state);
 	gts = kzalloc(bytes, GFP_KERNEL);
 	if (!gts)
@@ -316,21 +314,22 @@ static struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
 	STAT(gts_alloc);
 	atomic_set(&gts->ts_refcnt, 1);
 	mutex_init(&gts->ts_ctxlock);
-	gts->ts_cbr_au_count = vdata->vd_cbr_au_count;
-	gts->ts_dsr_au_count = vdata->vd_dsr_au_count;
-	gts->ts_user_options = vdata->vd_user_options;
+	gts->ts_cbr_au_count = cbr_au_count;
+	gts->ts_dsr_au_count = dsr_au_count;
+	gts->ts_user_options = options;
 	gts->ts_tsid = tsid;
-	gts->ts_user_options = vdata->vd_user_options;
 	gts->ts_ctxnum = NULLCTX;
-	gts->ts_mm = current->mm;
-	gts->ts_vma = vma;
 	gts->ts_tlb_int_select = -1;
-	gts->ts_gms = gru_register_mmu_notifier();
 	gts->ts_sizeavail = GRU_SIZEAVAIL(PAGE_SHIFT);
-	if (!gts->ts_gms)
-		goto err;
+	if (vma) {
+		gts->ts_mm = current->mm;
+		gts->ts_vma = vma;
+		gts->ts_gms = gru_register_mmu_notifier();
+		if (!gts->ts_gms)
+			goto err;
+	}
 
-	gru_dbg(grudev, "alloc vdata %p, new gts %p\n", vdata, gts);
+	gru_dbg(grudev, "alloc gts %p\n", gts);
 	return gts;
 
 err:
@@ -381,7 +380,8 @@ struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma,
 	struct gru_vma_data *vdata = vma->vm_private_data;
 	struct gru_thread_state *gts, *ngts;
 
-	gts = gru_alloc_gts(vma, vdata, tsid);
+	gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count, vdata->vd_dsr_au_count,
+			    vdata->vd_user_options, tsid);
 	if (!gts)
 		return NULL;
 
@@ -645,7 +645,7 @@ static int gru_retarget_intr(struct gru_thread_state *gts)
 #define next_gru(b, g)	(((g) < &(b)->bs_grus[GRU_CHIPLETS_PER_BLADE - 1]) ?  \
 				 ((g)+1) : &(b)->bs_grus[0])
 
-static void gru_steal_context(struct gru_thread_state *gts)
+static void gru_steal_context(struct gru_thread_state *gts, int blade_id)
 {
 	struct gru_blade_state *blade;
 	struct gru_state *gru, *gru0;
@@ -655,8 +655,7 @@ static void gru_steal_context(struct gru_thread_state *gts)
 	cbr = gts->ts_cbr_au_count;
 	dsr = gts->ts_dsr_au_count;
 
-	preempt_disable();
-	blade = gru_base[uv_numa_blade_id()];
+	blade = gru_base[blade_id];
 	spin_lock(&blade->bs_lock);
 
 	ctxnum = next_ctxnum(blade->bs_lru_ctxnum);
@@ -693,7 +692,6 @@ static void gru_steal_context(struct gru_thread_state *gts)
 	blade->bs_lru_gru = gru;
 	blade->bs_lru_ctxnum = ctxnum;
 	spin_unlock(&blade->bs_lock);
-	preempt_enable();
 
 	if (ngts) {
 		STAT(steal_context);
@@ -713,17 +711,17 @@ static void gru_steal_context(struct gru_thread_state *gts)
 /*
  * Scan the GRUs on the local blade & assign a GRU context.
  */
-static struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts)
+static struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts,
+						int blade)
 {
 	struct gru_state *gru, *grux;
 	int i, max_active_contexts;
 
-	preempt_disable();
 
 again:
 	gru = NULL;
 	max_active_contexts = GRU_NUM_CCH;
-	for_each_gru_on_blade(grux, uv_numa_blade_id(), i) {
+	for_each_gru_on_blade(grux, blade, i) {
 		if (check_gru_resources(grux, gts->ts_cbr_au_count,
 					gts->ts_dsr_au_count,
 					max_active_contexts)) {
@@ -763,7 +761,6 @@ again:
 		STAT(assign_context_failed);
 	}
 
-	preempt_enable();
 	return gru;
 }
 
@@ -778,6 +775,7 @@ int gru_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct gru_thread_state *gts;
 	unsigned long paddr, vaddr;
+	int blade_id;
 
 	vaddr = (unsigned long)vmf->virtual_address;
 	gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n",
@@ -792,8 +790,10 @@ int gru_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 again:
 	mutex_lock(&gts->ts_ctxlock);
 	preempt_disable();
+	blade_id = uv_numa_blade_id();
+
 	if (gts->ts_gru) {
-		if (gts->ts_gru->gs_blade_id != uv_numa_blade_id()) {
+		if (gts->ts_gru->gs_blade_id != blade_id) {
 			STAT(migrated_nopfn_unload);
 			gru_unload_context(gts, 1);
 		} else {
@@ -803,12 +803,14 @@ again:
 	}
 
 	if (!gts->ts_gru) {
-		if (!gru_assign_gru_context(gts)) {
-			mutex_unlock(&gts->ts_ctxlock);
+		if (!gru_assign_gru_context(gts, blade_id)) {
 			preempt_enable();
+			mutex_unlock(&gts->ts_ctxlock);
+			set_current_state(TASK_INTERRUPTIBLE);
 			schedule_timeout(GRU_ASSIGN_DELAY);  /* true hack ZZZ */
+			blade_id = uv_numa_blade_id();
 			if (gts->ts_steal_jiffies + GRU_STEAL_DELAY < jiffies)
-				gru_steal_context(gts);
+				gru_steal_context(gts, blade_id);
 			goto again;
 		}
 		gru_load_context(gts);
@@ -818,8 +820,8 @@ again:
 				vma->vm_page_prot);
 	}
 
-	mutex_unlock(&gts->ts_ctxlock);
 	preempt_enable();
+	mutex_unlock(&gts->ts_ctxlock);
 
 	return VM_FAULT_NOPAGE;
 }

drivers/misc/sgi-gru/grutables.h

@@ -630,6 +630,8 @@ extern void gru_flush_all_tlb(struct gru_state *gru);
 extern int gru_proc_init(void);
 extern void gru_proc_exit(void);
 
+extern struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
+		int cbr_au_count, int dsr_au_count, int options, int tsid);
 extern unsigned long gru_reserve_cb_resources(struct gru_state *gru,
 		int cbr_au_count, char *cbmap);
 extern unsigned long gru_reserve_ds_resources(struct gru_state *gru,