Author: alc
Date: Sat Jan 21 07:21:44 2012
New Revision: 230419
URL: http://svn.freebsd.org/changeset/base/230419
Log:
MFC r226163, r228317, and r228324
Fix the handling of an empty kmem map by sysctl_kmem_map_free().
Eliminate the possibility of 32-bit arithmetic overflow in the
calculation of vm_kmem_size that may occur if the system
administrator has specified a vm.vm_kmem_size tunable value that
exceeds the hard cap.
Eliminate stale numbers from a comment.
PR: 162741
Modified:
stable/8/sys/kern/kern_malloc.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)
Modified: stable/8/sys/kern/kern_malloc.c
==============================================================================
--- stable/8/sys/kern/kern_malloc.c Sat Jan 21 05:03:10 2012
(r230418)
+++ stable/8/sys/kern/kern_malloc.c Sat Jan 21 07:21:44 2012
(r230419)
@@ -258,8 +258,8 @@ sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS
u_long size;
vm_map_lock_read(kmem_map);
- size = kmem_map->root != NULL ?
- kmem_map->root->max_free : kmem_map->size;
+ size = kmem_map->root != NULL ? kmem_map->root->max_free :
+ kmem_map->max_offset - kmem_map->min_offset;
vm_map_unlock_read(kmem_map);
return (sysctl_handle_long(oidp, &size, 0, req));
}
@@ -595,12 +595,9 @@ kmeminit(void *dummy)
/*
* Try to auto-tune the kernel memory size, so that it is
- * more applicable for a wider range of machine sizes.
- * On an X86, a VM_KMEM_SIZE_SCALE value of 4 is good, while
- * a VM_KMEM_SIZE of 12MB is a fair compromise. The
+ * more applicable for a wider range of machine sizes. The
* VM_KMEM_SIZE_MAX is dependent on the maximum KVA space
- * available, and on an X86 with a total KVA space of 256MB,
- * try to keep VM_KMEM_SIZE_MAX at 80MB or below.
+ * available.
*
* Note that the kmem_map is also used by the zone allocator,
* so make sure that there is enough space.
@@ -637,11 +634,11 @@ kmeminit(void *dummy)
/*
* Limit kmem virtual size to twice the physical memory.
* This allows for kmem map sparseness, but limits the size
- * to something sane. Be careful to not overflow the 32bit
- * ints while doing the check.
+ * to something sane. Be careful to not overflow the 32bit
+ * ints while doing the check or the adjustment.
*/
- if (((vm_kmem_size / 2) / PAGE_SIZE) > cnt.v_page_count)
- vm_kmem_size = 2 * cnt.v_page_count * PAGE_SIZE;
+ if (vm_kmem_size / 2 / PAGE_SIZE > mem_size)
+ vm_kmem_size = 2 * mem_size * PAGE_SIZE;
/*
* Tune settings based on the kmem map's size at this time.
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