svn commit: r338743 - in head/sys: sys vm

[Mateusz Guzik]

Author: mjg
Date: Tue Sep 18 01:24:30 2018
New Revision: 338743
URL: https://svnweb.freebsd.org/changeset/base/338743

Log:
  vm: stop taking proc lock in mmap to satisfy racct if it is disabled
  
  Limits can be safely obtained with lim_cur from the thread. racct is compiled
  in but disabled by default. Note that racct enablement is a boot-only tunable.
  
  This eliminates second most common place of taking the lock while pkg building.
  
  While here don't take the lock in mlockall either.
  
  Reviewed by:	kib
  Approved by:	re (gjb)
  Differential Revision:	https://reviews.freebsd.org/D17210

Modified:
  head/sys/sys/racct.h
  head/sys/vm/vm_mmap.c

Modified: head/sys/sys/racct.h
==============================================================================
--- head/sys/sys/racct.h	Tue Sep 18 00:32:10 2018	(r338742)
+++ head/sys/sys/racct.h	Tue Sep 18 01:24:30 2018	(r338743)
@@ -164,6 +164,15 @@ extern struct mtx racct_lock;
 #define RACCT_UNLOCK()		mtx_unlock(&racct_lock)
 #define RACCT_LOCK_ASSERT()	mtx_assert(&racct_lock, MA_OWNED)
 
+#define	RACCT_PROC_LOCK(p)	do {		\
+	if (__predict_false(racct_enable))	\
+		PROC_LOCK(p);			\
+} while (0)
+#define	RACCT_PROC_UNLOCK(p)	do {		\
+	if (__predict_false(racct_enable))	\
+		PROC_UNLOCK(p);			\
+} while (0)
+
 int	racct_add(struct proc *p, int resource, uint64_t amount);
 void	racct_add_cred(struct ucred *cred, int resource, uint64_t amount);
 void	racct_add_force(struct proc *p, int resource, uint64_t amount);
@@ -188,6 +197,9 @@ void	racct_move(struct racct *dest, struct racct *src)
 void	racct_proc_throttle(struct proc *p, int timeout);
 
 #else
+
+#define	RACCT_PROC_LOCK(p)	do { } while (0)
+#define	RACCT_PROC_UNLOCK(p)	do { } while (0)
 
 static inline int
 racct_add(struct proc *p, int resource, uint64_t amount)

Modified: head/sys/vm/vm_mmap.c
==============================================================================
--- head/sys/vm/vm_mmap.c	Tue Sep 18 00:32:10 2018	(r338742)
+++ head/sys/vm/vm_mmap.c	Tue Sep 18 01:24:30 2018	(r338743)
@@ -1055,12 +1055,8 @@ sys_mlockall(struct thread *td, struct mlockall_args *
 	 * a hard resource limit, return ENOMEM.
 	 */
 	if (!old_mlock && uap->how & MCL_CURRENT) {
-		PROC_LOCK(td->td_proc);
-		if (map->size > lim_cur(td, RLIMIT_MEMLOCK)) {
-			PROC_UNLOCK(td->td_proc);
+		if (map->size > lim_cur(td, RLIMIT_MEMLOCK))
 			return (ENOMEM);
-		}
-		PROC_UNLOCK(td->td_proc);
 	}
 #ifdef RACCT
 	if (racct_enable) {
@@ -1445,21 +1441,21 @@ vm_mmap_object(vm_map_t map, vm_offset_t *addr, vm_siz
 
 	curmap = map == &td->td_proc->p_vmspace->vm_map;
 	if (curmap) {
-		PROC_LOCK(td->td_proc);
-		if (map->size + size > lim_cur_proc(td->td_proc, RLIMIT_VMEM)) {
-			PROC_UNLOCK(td->td_proc);
+		RACCT_PROC_LOCK(td->td_proc);
+		if (map->size + size > lim_cur(td, RLIMIT_VMEM)) {
+			RACCT_PROC_UNLOCK(td->td_proc);
 			return (ENOMEM);
 		}
 		if (racct_set(td->td_proc, RACCT_VMEM, map->size + size)) {
-			PROC_UNLOCK(td->td_proc);
+			RACCT_PROC_UNLOCK(td->td_proc);
 			return (ENOMEM);
 		}
 		if (!old_mlock && map->flags & MAP_WIREFUTURE) {
 			if (ptoa(pmap_wired_count(map->pmap)) + size >
-			    lim_cur_proc(td->td_proc, RLIMIT_MEMLOCK)) {
+			    lim_cur(td, RLIMIT_MEMLOCK)) {
 				racct_set_force(td->td_proc, RACCT_VMEM,
 				    map->size);
-				PROC_UNLOCK(td->td_proc);
+				RACCT_PROC_UNLOCK(td->td_proc);
 				return (ENOMEM);
 			}
 			error = racct_set(td->td_proc, RACCT_MEMLOCK,
@@ -1467,11 +1463,11 @@ vm_mmap_object(vm_map_t map, vm_offset_t *addr, vm_siz
 			if (error != 0) {
 				racct_set_force(td->td_proc, RACCT_VMEM,
 				    map->size);
-				PROC_UNLOCK(td->td_proc);
+				RACCT_PROC_UNLOCK(td->td_proc);
 				return (error);
 			}
 		}
-		PROC_UNLOCK(td->td_proc);
+		RACCT_PROC_UNLOCK(td->td_proc);
 	}
 
 	/*