Bring default logic to set nkmempages into the 21st century.

The new logic is:
Up to 1G physmem use physical memory / 4,
above 1G add an extra 16MB per 1G of memory.

Clamp it down depending on available kernel virtual address space
 - up and including 512M -> 64MB	(macppc, arm, sh)
 - between 512M and 1024M -> 128MB	(hppa, i386, mips, luna88k)
 - over 1024M clamping to VM_KERNEL_SPACE_SIZE / 4

The result is much more malloc(9) space on 64bit archs with lots of memory
and large kva space.
Note: amd64 only has 4G of kva and therefor nkmempages is limited to 262144

As a side-effect NKMEMPAGES_MAX and nkmempages_max are no longer used.
Tested and OK miod@

diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c
index 104a6bd..4c1446b 100644 (file)
--- a/sys/kern/kern_malloc.c
+++ b/sys/kern/kern_malloc.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_malloc.c,v 1.149 2023/11/29 11:47:15 claudio Exp $       */
+/*     $OpenBSD: kern_malloc.c,v 1.150 2023/12/14 11:58:09 claudio Exp $       */
 /*     $NetBSD: kern_malloc.c,v 1.15.4.2 1996/06/13 17:10:56 cgd Exp $ */
 
 /*
@@ -87,15 +87,6 @@ struct vm_map *kmem_map = NULL;
 #endif
 u_int  nkmempages = NKMEMPAGES;
 
-/*
- * Defaults for upper-bounds for the kmem_map page count.
- * Can be overridden by kernel config options.
- */
-#ifndef NKMEMPAGES_MAX
-#define        NKMEMPAGES_MAX  NKMEMPAGES_MAX_DEFAULT
-#endif
-u_int  nkmempages_max = NKMEMPAGES_MAX;
-
 struct mutex malloc_mtx = MUTEX_INITIALIZER(IPL_VM);
 struct kmembuckets bucket[MINBUCKET + 16];
 #ifdef KMEMSTATS
@@ -515,16 +506,26 @@ kmeminit_nkmempages(void)
        /*
         * We use the following (simple) formula:
         *
-        *      - Starting point is physical memory / 4.
-        *
-        *      - Clamp it down to nkmempages_max.
+        * Up to 1G physmem use physical memory / 4,
+        * above 1G add an extra 16MB per 1G of memory.
         *
-        *      - Round it up to nkmempages_min.
+        * Clamp it down depending on VM_KERNEL_SPACE_SIZE
+        * - up and including 512M -> 64MB
+        * - between 512M and 1024M -> 128MB
+        * - over 1024M clamping to VM_KERNEL_SPACE_SIZE / 4
         */
-       npages = physmem / 4;
-
-       if (npages > nkmempages_max)
-               npages = nkmempages_max;
+       npages = MIN(physmem, atop(1024 * 1024 * 1024)) / 4;
+       if (physmem > atop(1024 * 1024 * 1024))
+               npages += (physmem - atop(1024 * 1024 * 1024)) / 64;
+
+       if (VM_KERNEL_SPACE_SIZE <= 512 * 1024 * 1024) {
+               if (npages > atop(64 * 1024 * 1024))
+                       npages = atop(64 * 1024 * 1024);
+       } else if (VM_KERNEL_SPACE_SIZE <= 1024 * 1024 * 1024) {
+               if (npages > atop(128 * 1024 * 1024))
+                       npages = atop(128 * 1024 * 1024);
+       } else if (npages > atop(VM_KERNEL_SPACE_SIZE) / 4)
+               npages = atop(VM_KERNEL_SPACE_SIZE) / 4;
 
        nkmempages = npages;
 }
@@ -573,7 +574,8 @@ kmeminit(void)
                bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
        }
        for (indx = 0; indx < M_LAST; indx++)
-               kmemstats[indx].ks_limit = nkmempages * PAGE_SIZE * 6 / 10;
+               kmemstats[indx].ks_limit =
+                   (long)nkmempages * PAGE_SIZE * 6 / 10;
 #endif
 }