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Bug 1279387

Summary:	hugepage could not be used inside guest if start the guest with NUMA supported huge pages [7.2.z]
Product:	Red Hat Enterprise Linux 7	Reporter:	Jan Kurik <jkurik>
Component:	qemu-kvm-rhev	Assignee:	David Gibson <dgibson>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	high
Version:	7.2	CC:	abologna, dgibson, hannsj_uhl, jen, jkurik, knoel, mrezanin, ngu, qzhang, sherold, shuyu, virt-maint, xuhan, xuma, zhengtli
Target Milestone:	rc	Keywords:	ZStream
Target Release:	---
Hardware:	ppc64le
OS:	Unspecified
Whiteboard:
Fixed In Version:	qemu-kvm-rhev-2.3.0-31.el7_2.2	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:	1265576	Environment:
Last Closed:	2015-12-07 21:42:43 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1265576
Bug Blocks:	1201513

Description Jan Kurik 2015-11-09 11:08:35 UTC

This bug has been copied from bug #1265576 and has been proposed
to be backported to 7.2 z-stream (EUS).

Comment 4 Xujun Ma 2015-11-17 03:36:52 UTC

Verified the issue on the scratch build:
Version-Release number of selected component (if applicable):
Guest kernel: 3.10.0-327.e17.ppc64le
Host kernel:  3.10.0-327.el7.ppc64le
qemu-kvm-rhev-2.3.0-31.el7.next.candidate.ppc64le


Steps to Reproduce:
1.mount hugepage ,allocate hugepages ,and check hugepages on the host:
# mount -t hugetlbfs hugetlbfs /dev/hugepages -o pagesize=16M
# echo 256 > /proc/sys/vm/nr_hugepages 
# cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     256
HugePages_Free:      256
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

2. start a guest with command:
/usr/libexec/qemu-kvm \
 -m 4096M -smp 4 -monitor stdio -qmp tcp::8889,server,nowait  -vnc :26\
 -boot menu=on \
 -rtc base=utc,clock=vm \
 -netdev tap,id=tap0,script=/etc/qemu-ifup \
 -device virtio-net-pci,netdev=tap0,bootindex=3,id=net0,mac=24:be:05:11:92:11 \
 -drive file=sys1.qcow2,if=none,id=drive-0-0-0,format=qcow2,cache=none \
 -device virtio-blk-pci,drive=drive-0-0-0,bootindex=0,id=scsi0-0-0-0  \
 -device virtio-scsi-pci\
 -device scsi-cd,id=scsi-cd1,drive=scsi-cd1-dr,bootindex=1 \
 -drive file=RHEL-7.2-20151030.0-Server-ppc64le-dvd1.iso,if=none,id=scsi-cd1-dr,readonly=on,format=raw,cache=none \
 -object memory-backend-file,host-nodes=0,policy=interleave,id=mem-0,size=2048M,prealloc=yes,mem-path=/dev/hugepages\
 -numa node,memdev=mem-0,nodeid=1 \
 -object memory-backend-file,host-nodes=1,policy=interleave,id=mem-1,size=2048M,prealloc=yes,mem-path=/dev/hugepages \
 -numa node,memdev=mem-1,nodeid=0 \

3. check hugepages on the host :
# cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     256
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

4. check memory in guest :
#mount -t hugetlbfs hugetlbfs /mnt
#echo 256 > /proc/sys/vm/nr_hugepages
#cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     179
HugePages_Free:      179
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

# numactl  -H
available: 2 nodes (0-1)
node 0 cpus: 0 2
node 0 size: 2048 MB
node 0 free: 1239 MB
node 1 cpus: 1 3
node 1 size: 2048 MB
node 1 free: 1795 MB
node distances:
node   0   1 
  0:  10  40 
  1:  40  10 


Results: The hugepage can be used in guest if start the guest with NUMA supported 

so the bug has been fixed.

Comment 5 Miroslav Rezanina 2015-11-18 10:07:44 UTC

Fix included in qemu-kvm-rhev-2.3.0-31.el7_2.2

Comment 6 Xujun Ma 2015-11-20 03:24:26 UTC

Reproduced the issue on old version:

Version-Release number of selected component (if applicable):
Guest kernel: 3.10.0-327.el7.ppc64le
qemu-kvm-rhev:qemu-kvm-rhev-2.3.0-23.el7.ppc64le
Host kernel:3.10.0-316.el7.ppc64le


Steps to Reproduce:
1.mount hugepage ,allocate hugepages ,and check hugepages on the host:
# mount -t hugetlbfs hugetlbfs /dev/hugepages -o pagesize=16M
# echo 128 > /proc/sys/vm/nr_hugepages 
# cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     128
HugePages_Free:      128
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

2. start a guest with command:
/usr/libexec/qemu-kvm \
 -m 2048M -smp 4 -monitor stdio -qmp tcp::8889,server,nowait  -vnc :26\
 -boot menu=on \
 -rtc base=utc,clock=vm \
 -netdev tap,id=tap0,script=/etc/qemu-ifup \
 -device virtio-net-pci,netdev=tap0,bootindex=3,id=net0,mac=24:be:05:11:92:11 \
 -drive file=sys1.qcow2,if=none,id=drive-0-0-0,format=qcow2,cache=none \
 -device virtio-blk-pci,drive=drive-0-0-0,bootindex=0,id=scsi0-0-0-0  \
 -device virtio-scsi-pci\
 -device scsi-cd,id=scsi-cd1,drive=scsi-cd1-dr,bootindex=1 \
 -drive file=RHEL-7.2-20151030.0-Server-ppc64le-dvd1.iso,if=none,id=scsi-cd1-dr,readonly=on,format=raw,cache=none \
 -object memory-backend-file,host-nodes=0,policy=interleave,id=mem-0,size=2048M,prealloc=yes,mem-path=/dev/hugepages\
 -numa node,memdev=mem-0,nodeid=0\


3. check hugepages on the host :
# cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     128
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

4. check memory in guest :
#mount -t hugetlbfs hugetlbfs /mnt
mount: unknown filesystem type 'hugetlbfs'

#mount -t hugetlbfs hugetlbfs /dev/hugepages -o pagesize=16M
mount: mount point /dev/hugepages does not exist

#echo 256 > /proc/sys/vm/nr_hugepages
-bash: echo: write error: Success

#cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB

# numactl  -H
available: 1 nodes (0)
node 0 cpus: 0 1 2 3
node 0 size: 2048 MB
node 0 free: 1092 MB
node distances:
node   0 
  0:  10


Results: The hugepage can't be used in guest if start the guest with NUMA supported 


Verified the issue on the latest build:
Version-Release number of selected component (if applicable):
Guest kernel: 3.10.0-327.el7.ppc64le
qemu-kvm-rhev:qemu-img-rhev-2.3.0-31.el7_2.2.ppc64le
Host kernel:3.10.0-327.el7.ppc64le


Steps to Reproduce:
1.mount hugepage ,allocate hugepages ,and check hugepages on the host:
# mount -t hugetlbfs hugetlbfs /dev/hugepages -o pagesize=16M
# echo 128 > /proc/sys/vm/nr_hugepages 
# cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     128
HugePages_Free:      128
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

2. start a guest with command:
/usr/libexec/qemu-kvm \
 -m 2048M -smp 4 -monitor stdio -qmp tcp::8889,server,nowait  -vnc :26\
 -boot menu=on \
 -rtc base=utc,clock=vm \
 -netdev tap,id=tap0,script=/etc/qemu-ifup \
 -device virtio-net-pci,netdev=tap0,bootindex=3,id=net0,mac=24:be:05:11:92:11 \
 -drive file=sys1.qcow2,if=none,id=drive-0-0-0,format=qcow2,cache=none \
 -device virtio-blk-pci,drive=drive-0-0-0,bootindex=0,id=scsi0-0-0-0  \
 -device virtio-scsi-pci\
 -device scsi-cd,id=scsi-cd1,drive=scsi-cd1-dr,bootindex=1 \
 -drive file=RHEL-7.2-20151030.0-Server-ppc64le-dvd1.iso,if=none,id=scsi-cd1-dr,readonly=on,format=raw,cache=none \
 -object memory-backend-file,host-nodes=0,policy=interleave,id=mem-0,size=2048M,prealloc=yes,mem-path=/dev/hugepages\
 -numa node,memdev=mem-0,nodeid=0\


3. check hugepages on the host :
# cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:     128
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

4. check memory in guest :
#mount -t hugetlbfs hugetlbfs /mnt

#mount -t hugetlbfs hugetlbfs /dev/hugepages -o pagesize=16M

#echo 128 > /proc/sys/vm/nr_hugepages

#cat /proc/meminfo |grep -i HugePages
AnonHugePages:         0 kB
HugePages_Total:      64
HugePages_Free:       64
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:      16384 kB

# numactl  -H
available: 1 nodes (0)
node 0 cpus: 0 1 2 3
node 0 size: 2048 MB
node 0 free: 176 MB
node distances:
node   0 
  0:  10


Results: The hugepage can be used in guest if start the guest with NUMA supported ,so the bug has beed fixed in qemu-kvm-rhev-2.3.0-31.el7_2.2

Comment 10 errata-xmlrpc 2015-12-07 21:42:43 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-2555.html