The following reply was made to PR kern/162741; it has been noted by GNATS.
From: dfil...@freebsd.org (dfilter service) To: bug-follo...@freebsd.org Cc: Subject: Re: kern/162741: commit references a PR Date: Sat, 21 Jan 2012 07:57:38 +0000 (UTC) Author: alc Date: Sat Jan 21 07:57:27 2012 New Revision: 230420 URL: http://svn.freebsd.org/changeset/base/230420 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/7/sys/kern/kern_malloc.c Directory Properties: stable/7/sys/ (props changed) stable/7/sys/cddl/contrib/opensolaris/ (props changed) stable/7/sys/contrib/dev/acpica/ (props changed) stable/7/sys/contrib/pf/ (props changed) Modified: stable/7/sys/kern/kern_malloc.c ============================================================================== --- stable/7/sys/kern/kern_malloc.c Sat Jan 21 07:21:44 2012 (r230419) +++ stable/7/sys/kern/kern_malloc.c Sat Jan 21 07:57:27 2012 (r230420) @@ -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)); } @@ -594,12 +594,9 @@ 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. @@ -640,11 +637,11 @@ 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. _______________________________________________ svn-src-...@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org" _______________________________________________ freebsd-bugs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
