Date: Mon, 2 Aug 2010 21:33:38 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r210782 - head/sys/kern Message-ID: <201008022133.o72LXcvH043281@svn.freebsd.org>
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Author: alc Date: Mon Aug 2 21:33:36 2010 New Revision: 210782 URL: http://svn.freebsd.org/changeset/base/210782 Log: Update the "desiredvnodes" calculation. In particular, make the part of 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 Modified: head/sys/kern/vfs_subr.c Modified: head/sys/kern/vfs_subr.c ============================================================================== --- head/sys/kern/vfs_subr.c Mon Aug 2 19:56:07 2010 (r210781) +++ head/sys/kern/vfs_subr.c Mon Aug 2 21:33:36 2010 (r210782) @@ -282,23 +282,34 @@ SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhe /* * 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 = min(maxproc + cnt.v_page_count / 4, 2 * vm_kmem_size / - (5 * (sizeof(struct vm_object) + sizeof(struct vnode)))); + * 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. + */ + 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",
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