De-ifdef UVM_AMAP_PPREF it's been enabled long enough to not go back

Fewer knobs and conditional code that nobody tests.

deraadt@: go for it

sys/uvm/uvm_amap.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_amap.c,v 1.96 2024/12/04 09:19:11 mpi Exp $	*/
+/*	$OpenBSD: uvm_amap.c,v 1.97 2025/05/25 01:52:00 gnezdo Exp $	*/
 /*	$NetBSD: uvm_amap.c,v 1.27 2000/11/25 06:27:59 chs Exp $	*/
 
 /*
@@ -72,13 +72,6 @@ static inline void amap_list_remove(struct vm_amap *);
 struct vm_amap_chunk *amap_chunk_get(struct vm_amap *, int, int, int);
 void amap_chunk_free(struct vm_amap *, struct vm_amap_chunk *);
 
-/*
- * if we enable PPREF, then we have a couple of extra functions that
- * we need to prototype here...
- */
-
-#ifdef UVM_AMAP_PPREF
-
 #define PPREF_NONE ((int *) -1)	/* not using ppref */
 
 void	amap_pp_adjref(struct vm_amap *, int, vsize_t, int);
@@ -87,8 +80,6 @@ void	amap_wiperange_chunk(struct vm_amap *, struct vm_amap_chunk *, int,
 	    int);
 void	amap_wiperange(struct vm_amap *, int, int);
 
-#endif	/* UVM_AMAP_PPREF */
-
 static inline void
 amap_list_insert(struct vm_amap *amap)
 {
@@ -179,13 +170,11 @@ amap_chunk_free(struct vm_amap *amap, struct vm_amap_chunk *chunk)
 	amap->am_ncused--;
 }
 
-#ifdef UVM_AMAP_PPREF
 /*
  * what is ppref?   ppref is an _optional_ amap feature which is used
- * to keep track of reference counts on a per-page basis.  it is enabled
- * when UVM_AMAP_PPREF is defined.
+ * to keep track of reference counts on a per-page basis.
  *
- * when enabled, an array of ints is allocated for the pprefs.  this
+ * an array of ints is allocated for the pprefs.  this
  * array is allocated only when a partial reference is added to the
  * map (either by unmapping part of the amap, or gaining a reference
  * to only a part of an amap).  if the allocation of the array fails
@@ -246,7 +235,6 @@ pp_setreflen(int *ppref, int offset, int ref, int len)
 		ppref[offset+1] = len;
 	}
 }
-#endif /* UVM_AMAP_PPREF */
 
 /*
  * amap_init: called at boot time to init global amap data structures
@@ -347,9 +335,7 @@ amap_alloc1(int slots, int waitf, int lazyalloc)
 	amap->am_lock = NULL;
 	amap->am_ref = 1;
 	amap->am_flags = 0;
-#ifdef UVM_AMAP_PPREF
 	amap->am_ppref = NULL;
-#endif
 	amap->am_nslot = slots;
 	amap->am_nused = 0;
 
@@ -454,10 +440,8 @@ amap_free(struct vm_amap *amap)
 		rw_obj_free(amap->am_lock);
 	}
 
-#ifdef UVM_AMAP_PPREF
 	if (amap->am_ppref && amap->am_ppref != PPREF_NONE)
 		free(amap->am_ppref, M_UVMAMAP, amap->am_nslot * sizeof(int));
-#endif
 
 	if (UVM_AMAP_SMALL(amap))
 		pool_put(&uvm_small_amap_pool[amap->am_nslot - 1], amap);
@@ -688,12 +672,10 @@ amap_copy(struct vm_map *map, struct vm_map_entry *entry, int waitf,
 
 	if (srcamap->am_ref == 1 && (srcamap->am_flags & AMAP_SHARED) != 0)
 		srcamap->am_flags &= ~AMAP_SHARED;   /* clear shared flag */
-#ifdef UVM_AMAP_PPREF
 	if (srcamap->am_ppref && srcamap->am_ppref != PPREF_NONE) {
 		amap_pp_adjref(srcamap, entry->aref.ar_pageoff, 
 		    (entry->end - entry->start) >> PAGE_SHIFT, -1);
 	}
-#endif
 
 	/*
 	 * If we referenced any anons, then share the source amap's lock.
@@ -854,11 +836,9 @@ amap_splitref(struct vm_aref *origref, struct vm_aref *splitref, vaddr_t offset)
 	if (amap->am_nslot - origref->ar_pageoff - leftslots <= 0)
 		panic("amap_splitref: map size check failed");
 
-#ifdef UVM_AMAP_PPREF
 	/* Establish ppref before we add a duplicate reference to the amap. */
 	if (amap->am_ppref == NULL)
 		amap_pp_establish(amap);
-#endif
 
 	/* Note: not a share reference. */
 	amap->am_ref++;
@@ -867,8 +847,6 @@ amap_splitref(struct vm_aref *origref, struct vm_aref *splitref, vaddr_t offset)
 	amap_unlock(amap);
 }
 
-#ifdef UVM_AMAP_PPREF
-
 /*
  * amap_pp_establish: add a ppref array to an amap, if possible.
  *
@@ -1065,8 +1043,6 @@ amap_wiperange(struct vm_amap *amap, int slotoff, int slots)
 	}
 }
 
-#endif
-
 /*
  * amap_swap_off: pagein anonymous pages in amaps and drop swap slots.
  *
@@ -1303,7 +1279,6 @@ static void
 amap_adjref_anons(struct vm_amap *amap, vaddr_t offset, vsize_t len,
     int refv, boolean_t all)
 {
-#ifdef UVM_AMAP_PPREF
 	KASSERT(rw_write_held(amap->am_lock));
 
 	/*
@@ -1313,11 +1288,8 @@ amap_adjref_anons(struct vm_amap *amap, vaddr_t offset, vsize_t len,
 	if (amap->am_ppref == NULL && !all && len != amap->am_nslot) {
 		amap_pp_establish(amap);
 	}
-#endif
-
 	amap->am_ref += refv;
 
-#ifdef UVM_AMAP_PPREF
 	if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
 		if (all) {
 			amap_pp_adjref(amap, 0, amap->am_nslot, refv);
@@ -1325,7 +1297,6 @@ amap_adjref_anons(struct vm_amap *amap, vaddr_t offset, vsize_t len,
 			amap_pp_adjref(amap, offset, len, refv);
 		}
 	}
-#endif
 	amap_unlock(amap);
 }
 

sys/uvm/uvm_amap.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_amap.h,v 1.35 2024/12/04 09:19:11 mpi Exp $	*/
+/*	$OpenBSD: uvm_amap.h,v 1.36 2025/05/25 01:52:00 gnezdo Exp $	*/
 /*	$NetBSD: uvm_amap.h,v 1.14 2001/02/18 21:19:08 chs Exp $	*/
 
 /*
@@ -112,13 +112,10 @@ boolean_t	amap_swap_off(int, int);
 
 /*
  * we currently provide an array-based amap implementation.  in this
- * implementation we provide the option of tracking split references
- * so that we don't lose track of references during partial unmaps
- * ... this is enabled with the "UVM_AMAP_PPREF" define.
+ * implementation we track split references so that we don't lose track of
+ * references during partial unmaps.
  */
 
-#define UVM_AMAP_PPREF		/* track partial references */
-
 /*
  * here is the definition of the vm_amap structure and helper structures for
  * this implementation.
@@ -138,9 +135,7 @@ struct vm_amap {
 	int am_flags;		/* flags */
 	int am_nslot;		/* # of slots currently in map */
 	int am_nused;		/* # of slots currently in use */
-#ifdef UVM_AMAP_PPREF
 	int *am_ppref;		/* per page reference count (if !NULL) */
-#endif
 	LIST_ENTRY(vm_amap) am_list;
 
 	union {