On Alan's advice, rather than do a wholesale conversion on a single

architecture from page queue lock to a hashed array of page locks
(based on a patch by Jeff Roberson), I've implemented page lock
support in the MI code and have only moved vm_page's hold_count
out from under page queue mutex to page lock. This changes
pmap_extract_and_hold on all pmaps.

Supported by: Bitgravity Inc.

Discussed with: alc, jeffr, and kib

2 files changed, 8 insertions, 2 deletions

diff --git a/sys/sun4v/include/pmap.h b/sys/sun4v/include/pmap.h
index 90ae4c4..6acebb4 100644
--- a/sys/sun4v/include/pmap.h
+++ b/sys/sun4v/include/pmap.h
@@ -75,6 +75,8 @@ struct pmap {
 	struct tte_hash        *pm_hash;
 	TAILQ_HEAD(,pv_entry)	pm_pvlist;	/* list of mappings in pmap */
 	struct hv_tsb_info      pm_tsb;
+	uint32_t		pm_gen_count;	/* generation count (pmap lock dropped) */
+	u_int			pm_retries;
 	pmap_cpumask_t          pm_active;      /* mask of cpus currently using pmap */
 	pmap_cpumask_t          pm_tlbactive;   /* mask of cpus that have used this pmap */
 	struct	pmap_statistics pm_stats;
diff --git a/sys/sun4v/sun4v/pmap.c b/sys/sun4v/sun4v/pmap.c
index cbd8106..0c84421 100644
--- a/sys/sun4v/sun4v/pmap.c
+++ b/sys/sun4v/sun4v/pmap.c
@@ -1275,17 +1275,21 @@ pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
 {
 	tte_t tte_data;
 	vm_page_t m;
+	vm_paddr_t pa;
 
 	m = NULL;
-	vm_page_lock_queues();
+	pa = 0;
 	PMAP_LOCK(pmap);
+retry:	
 	tte_data = tte_hash_lookup(pmap->pm_hash, va);
 	if (tte_data != 0 && 
 	    ((tte_data & VTD_SW_W) || (prot & VM_PROT_WRITE) == 0)) {
+		if (vm_page_pa_tryrelock(pmap, TTE_GET_PA(tte_data), &pa))
+			goto retry;
 		m = PHYS_TO_VM_PAGE(TTE_GET_PA(tte_data));
 		vm_page_hold(m);
 	}
-	vm_page_unlock_queues();
+	PA_UNLOCK_COND(pa);
 	PMAP_UNLOCK(pmap);
 
 	return (m);