Index: uvm_pdaemon.c
===================================================================
RCS file: /cvsroot/src/sys/uvm/uvm_pdaemon.c,v
retrieving revision 1.107
diff -p -r1.107 uvm_pdaemon.c
*** uvm_pdaemon.c	30 Jul 2012 23:56:48 -0000	1.107
--- uvm_pdaemon.c	5 Oct 2012 00:31:27 -0000
*************** uvm_pageout(void *arg)
*** 232,237 ****
--- 232,241 ----
  	int bufcnt, npages = 0;
  	int extrapages = 0;
  	struct pool *pp;
+ 	/* XXX make this sysctl read/write */
+ 	int max_concurrent_loops = 1024;
+ 	/* XXX make this sysctl read */
+ 	int current_loop = 0;
  	
  	UVMHIST_FUNC("uvm_pageout"); UVMHIST_CALLED(pdhist);
  
*************** uvm_pageout(void *arg)
*** 251,269 ****
  	 * main loop
  	 */
  
! 	for (;;) {
  		bool needsscan, needsfree, kmem_va_starved;
  
  		kmem_va_starved = uvm_km_va_starved_p();
  
  		mutex_spin_enter(&uvm_fpageqlock);
! 		if ((uvm_pagedaemon_waiters == 0 || uvmexp.paging > 0) &&
! 		    !kmem_va_starved) {
  			UVMHIST_LOG(pdhist,"  <<SLEEPING>>",0,0,0,0);
  			UVM_UNLOCK_AND_WAIT(&uvm.pagedaemon,
! 			    &uvm_fpageqlock, false, "pgdaemon", 0);
  			uvmexp.pdwoke++;
  			UVMHIST_LOG(pdhist,"  <<WOKE UP>>",0,0,0,0);
  		} else {
  			mutex_spin_exit(&uvm_fpageqlock);
  		}
--- 255,279 ----
  	 * main loop
  	 */
  
! 	for (;; current_loop++) {
  		bool needsscan, needsfree, kmem_va_starved;
  
  		kmem_va_starved = uvm_km_va_starved_p();
  
  		mutex_spin_enter(&uvm_fpageqlock);
! 		if (current_loop > max_concurrent_loops ||
! 		    ((uvm_pagedaemon_waiters == 0 || uvmexp.paging > 0) &&
! 		     !kmem_va_starved)) {
! 			int timo = 0;
! 
! 			if (current_loop > max_concurrent_loops)
! 				timo = hz;
  			UVMHIST_LOG(pdhist,"  <<SLEEPING>>",0,0,0,0);
  			UVM_UNLOCK_AND_WAIT(&uvm.pagedaemon,
! 			    &uvm_fpageqlock, false, "pgdaemon", timo);
  			uvmexp.pdwoke++;
  			UVMHIST_LOG(pdhist,"  <<WOKE UP>>",0,0,0,0);
+ 			current_loop = 0;
  		} else {
  			mutex_spin_exit(&uvm_fpageqlock);
  		}