Date: Thu, 14 Feb 2019 15:34:10 -0800 From: Gleb Smirnoff <glebius@freebsd.org> To: Justin Hibbits <chmeeedalf@gmail.com> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r343030 - in head/sys: cam conf dev/md dev/nvme fs/fuse fs/nfsclient fs/smbfs kern sys ufs/ffs vm Message-ID: <20190214233410.GJ83215@FreeBSD.org> In-Reply-To: <20190213192450.32343d6a@ralga.knownspace> References: <201901150102.x0F12Hlt025856@repo.freebsd.org> <20190213192450.32343d6a@ralga.knownspace>
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Hi Justin,
On Wed, Feb 13, 2019 at 07:24:50PM -0600, Justin Hibbits wrote:
J> This seems to break 32-bit platforms, or at least 32-bit book-e
J> powerpc, which has a limited KVA space (~500MB). It preallocates I've
J> seen over 2500 pbufs, at 128kB each, eating up over 300MB KVA,
J> leaving very little left for the rest of runtime.
J>
J> I spent a couple hours earlier today debugging with Mark Johnston, and
J> his consensus is that the vnode_pbuf_zone is too big on 32-bit
J> platforms. Unfortunately I know very little about this area, so can't
J> provide much extra insight, but can readily reproduce the issues I see
J> triggered by this change, so am willing to help where I can.
Ok, let's roll back to old default on 32-bit platforms and somewhat
reduce the default on 64-bits.
Can you please confirm that the patch attached works for you?
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Gleb Smirnoff
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diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c
index 3e71ab4436cc..ded9e65e4e4c 100644
--- a/sys/vm/vnode_pager.c
+++ b/sys/vm/vnode_pager.c
@@ -115,13 +115,23 @@ SYSCTL_PROC(_debug, OID_AUTO, vnode_domainset, CTLTYPE_STRING | CTLFLAG_RW,
&vnode_domainset, 0, sysctl_handle_domainset, "A",
"Default vnode NUMA policy");
+static int nvnpbufs;
+SYSCTL_INT(_vm, OID_AUTO, vnode_pbufs, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
+ &nvnpbufs, 0, "number of physical buffers allocated for vnode pager");
+
static uma_zone_t vnode_pbuf_zone;
static void
vnode_pager_init(void *dummy)
{
- vnode_pbuf_zone = pbuf_zsecond_create("vnpbuf", nswbuf * 8);
+#ifdef __LP64__
+ nvnpbufs = nswbuf * 2;
+#else
+ nvnpbufs = nswbuf / 2;
+#endif
+ TUNABLE_INT_FETCH("vm.vnode_pbufs", &nvnpbufs);
+ vnode_pbuf_zone = pbuf_zsecond_create("vnpbuf", nvnpbufs);
}
SYSINIT(vnode_pager, SI_SUB_CPU, SI_ORDER_ANY, vnode_pager_init, NULL);
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