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Update the "desiredvnodes" calculation. In particular, make the part of

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the calculation that is based on the kernel's heap size more conservative.
Hopefully, this will eliminate the need for MAXVNODES_MAX, but for the
time being set MAXVNODES_MAX to a large value.

Reviewed by:	jhb@
MFC after:	6 weeks
This commit is contained in:
Alan Cox 2010-08-02 21:33:36 +00:00
parent 6305bb243c
commit 1d7fe4b515
1 changed files with 19 additions and 8 deletions
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27
sys/kern/vfs_subr.c
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@ -282,23 +282,34 @@ SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
/*
* Initialize the vnode management data structures.
*
* Reevaluate the following cap on the number of vnodes after the physical
* memory size exceeds 512GB. In the limit, as the physical memory size
* grows, the ratio of physical pages to vnodes approaches sixteen to one.
*/
#ifndef MAXVNODES_MAX
#define MAXVNODES_MAX 100000
#define MAXVNODES_MAX (512 * (1024 * 1024 * 1024 / PAGE_SIZE / 16))
#endif
static void
vntblinit(void *dummy __unused)
{
int physvnodes, virtvnodes;
/*
* Desiredvnodes is a function of the physical memory size and
* the kernel's heap size. Specifically, desiredvnodes scales
* in proportion to the physical memory size until two fifths
* of the kernel's heap size is consumed by vnodes and vm
* objects.
* Desiredvnodes is a function of the physical memory size and the
* kernel's heap size. Generally speaking, it scales with the
* physical memory size. The ratio of desiredvnodes to physical pages
* is one to four until desiredvnodes exceeds 98,304. Thereafter, the
* marginal ratio of desiredvnodes to physical pages is one to
* sixteen. However, desiredvnodes is limited by the kernel's heap
* size. The memory required by desiredvnodes vnodes and vm objects
* may not exceed one seventh of the kernel's heap size.
*/
desiredvnodes = min(maxproc + cnt.v_page_count / 4, 2 * vm_kmem_size /
(5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
physvnodes = maxproc + cnt.v_page_count / 16 + 3 * min(98304 * 4,
cnt.v_page_count) / 16;
virtvnodes = vm_kmem_size / (7 * (sizeof(struct vm_object) +
sizeof(struct vnode)));
desiredvnodes = min(physvnodes, virtvnodes);
if (desiredvnodes > MAXVNODES_MAX) {
if (bootverbose)
printf("Reducing kern.maxvnodes %d -> %d\n",