svn commit: r207596 - in stable/8/sys: kern sys vm

[Konstantin Belousov]

Author: kib
Date: Tue May  4 05:14:43 2010
New Revision: 207596
URL: http://svn.freebsd.org/changeset/base/207596

Log:
  MFC r206264:
  When OOM searches for a process to kill, ignore the processes already
  killed by OOM. When killed process waits for a page allocation, try to
  satisfy the request as fast as possible.

Modified:
  stable/8/sys/kern/kern_sig.c
  stable/8/sys/sys/proc.h
  stable/8/sys/vm/vm_fault.c
  stable/8/sys/vm/vm_pageout.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)
  stable/8/sys/geom/sched/   (props changed)

Modified: stable/8/sys/kern/kern_sig.c
==============================================================================
--- stable/8/sys/kern/kern_sig.c	Tue May  4 04:04:37 2010	(r207595)
+++ stable/8/sys/kern/kern_sig.c	Tue May  4 05:14:43 2010	(r207596)
@@ -2801,6 +2801,7 @@ killproc(p, why)
 		p, p->p_pid, p->p_comm);
 	log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
 		p->p_ucred ? p->p_ucred->cr_uid : -1, why);
+	p->p_flag |= P_WKILLED;
 	psignal(p, SIGKILL);
 }
 

Modified: stable/8/sys/sys/proc.h
==============================================================================
--- stable/8/sys/sys/proc.h	Tue May  4 04:04:37 2010	(r207595)
+++ stable/8/sys/sys/proc.h	Tue May  4 05:14:43 2010	(r207596)
@@ -575,7 +575,7 @@ struct proc {
 #define	P_WAITED	0x01000	/* Someone is waiting for us. */
 #define	P_WEXIT		0x02000	/* Working on exiting. */
 #define	P_EXEC		0x04000	/* Process called exec. */
-#define	P_UNUSED8000	0x08000	/* available. */
+#define	P_WKILLED	0x08000	/* Killed, go to kernel/user boundary ASAP. */
 #define	P_CONTINUED	0x10000	/* Proc has continued from a stopped state. */
 #define	P_STOPPED_SIG	0x20000	/* Stopped due to SIGSTOP/SIGTSTP. */
 #define	P_STOPPED_TRACE	0x40000	/* Stopped because of tracing. */
@@ -594,6 +594,7 @@ struct proc {
 
 #define	P_STOPPED	(P_STOPPED_SIG|P_STOPPED_SINGLE|P_STOPPED_TRACE)
 #define	P_SHOULDSTOP(p)	((p)->p_flag & P_STOPPED)
+#define	P_KILLED(p)	((p)->p_flag & P_WKILLED)
 
 /*
  * These were process status values (p_stat), now they are only used in

Modified: stable/8/sys/vm/vm_fault.c
==============================================================================
--- stable/8/sys/vm/vm_fault.c	Tue May  4 04:04:37 2010	(r207595)
+++ stable/8/sys/vm/vm_fault.c	Tue May  4 05:14:43 2010	(r207596)
@@ -217,7 +217,7 @@ vm_fault(vm_map_t map, vm_offset_t vaddr
 	vm_object_t next_object;
 	vm_page_t marray[VM_FAULT_READ];
 	int hardfault;
-	int faultcount, ahead, behind;
+	int faultcount, ahead, behind, alloc_req;
 	struct faultstate fs;
 	struct vnode *vp;
 	int locked, error;
@@ -414,9 +414,14 @@ RetryFault:;
 
 			/*
 			 * Allocate a new page for this object/offset pair.
+			 *
+			 * Unlocked read of the p_flag is harmless. At
+			 * worst, the P_KILLED might be not observed
+			 * there, and allocation can fail, causing
+			 * restart and new reading of the p_flag.
 			 */
 			fs.m = NULL;
-			if (!vm_page_count_severe()) {
+			if (!vm_page_count_severe() || P_KILLED(curproc)) {
 #if VM_NRESERVLEVEL > 0
 				if ((fs.object->flags & OBJ_COLORED) == 0) {
 					fs.object->flags |= OBJ_COLORED;
@@ -424,10 +429,13 @@ RetryFault:;
 					    fs.pindex;
 				}
 #endif
+				alloc_req = P_KILLED(curproc) ?
+				    VM_ALLOC_SYSTEM : VM_ALLOC_NORMAL;
+				if (fs.object->type != OBJT_VNODE &&
+				    fs.object->backing_object == NULL)
+					alloc_req |= VM_ALLOC_ZERO;
 				fs.m = vm_page_alloc(fs.object, fs.pindex,
-				    (fs.object->type == OBJT_VNODE ||
-				     fs.object->backing_object != NULL) ?
-				    VM_ALLOC_NORMAL : VM_ALLOC_ZERO);
+				    alloc_req);
 			}
 			if (fs.m == NULL) {
 				unlock_and_deallocate(&fs);
@@ -452,7 +460,8 @@ readrest:
 			int reqpage = 0;
 			u_char behavior = vm_map_entry_behavior(fs.entry);
 
-			if (behavior == MAP_ENTRY_BEHAV_RANDOM) {
+			if (behavior == MAP_ENTRY_BEHAV_RANDOM ||
+			    P_KILLED(curproc)) {
 				ahead = 0;
 				behind = 0;
 			} else {

Modified: stable/8/sys/vm/vm_pageout.c
==============================================================================
--- stable/8/sys/vm/vm_pageout.c	Tue May  4 04:04:37 2010	(r207595)
+++ stable/8/sys/vm/vm_pageout.c	Tue May  4 05:14:43 2010	(r207596)
@@ -1206,10 +1206,10 @@ vm_pageout_oom(int shortage)
 		if (PROC_TRYLOCK(p) == 0)
 			continue;
 		/*
-		 * If this is a system or protected process, skip it.
+		 * If this is a system, protected or killed process, skip it.
 		 */
 		if ((p->p_flag & (P_INEXEC | P_PROTECTED | P_SYSTEM)) ||
-		    (p->p_pid == 1) ||
+		    (p->p_pid == 1) || P_KILLED(p) ||
 		    ((p->p_pid < 48) && (swap_pager_avail != 0))) {
 			PROC_UNLOCK(p);
 			continue;