after re-check , the first bad commit is:
commit 3e469dbfe413c25d48321c3a19ddfae0727dc6e5
Author: Andrea Arcangeli <aarca...@redhat.com>
Date: Thu Jul 25 12:11:15 2013 +0200
exec: always use MADV_DONTFORK
MADV_DONTFORK prevents fork to fail with -ENOMEM if the default
overcommit heuristics decides there's too much anonymous virtual
memory allocated. If the KVM secondary MMU is synchronized with MMU
notifiers or not, doesn't make a difference in that regard.
Secondly it's always more efficient to avoid copying the guest
physical address space in the fork child (so we avoid to mark all the
guest memory readonly in the parent and so we skip the establishment
and teardown of lots of pagetables in the child).
In the common case we can ignore the error if MADV_DONTFORK is not
available. Leave a second invocation that errors out in the KVM path
if MMU notifiers are missing and KVM is enabled, to abort in such
case.
Signed-off-by: Andrea Arcangeli <aarca...@redhat.com>
Tested-By: Benoit Canet <ben...@irqsave.net>
Acked-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Gleb Natapov <g...@redhat.com>
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https://bugs.launchpad.net/bugs/1261268
Title:
save guest running time is more than 450s with AVX running.
Status in QEMU:
New
Bug description:
Environment:
------------
Host OS (ia32/ia32e/IA64):ia32e
Guest OS (ia32/ia32e/IA64):ia32e
Guest OS Type (Linux/Windows):linux
kvm.git Commit:d6d63b51fe3bfea0cf596993afa480b0b3b02c32
qemu.git Commit:8f84271da83c0e9f92aa7c1c2d0d3875bf0a5cb8
Host Kernel Version:3.13.0-rc1
Hardware:Romley_EP, Ivytown_EP
Bug detailed description:
--------------------------
when guest running avx , then do save /restore, save guest running time is
too lomg
Note:
1.when save guest (migrate "exec:dd of=test.img")sometimes , the file of
test.img is 29G, running time of save guest is about 900s
2. this should be a qemu bug:
kvm + qemu = result
d6d63b51 + 8f84271d = bad
d6d63b51 + b5d54bd4 = good
Reproduce steps:
----------------
1.qemu-system-x86_64 -enable-kvm -m 1024 -smp 6 -net
nic,macaddr=00:12:34:43:14:78 -net tap,script=/etc/kvm/qemu-ifup rhel6u4.qcow
2. scp /usr/tet/XVS/tsets/control_panel/tools/bin/avx.tar.gz $guest_IP:/root
3. tar -zxf avx.tar.gz
4. cd /avx
5. sh chk_avx.sh &>/dev/null &
6. ctrl-alt-2
7. migrate "exec:dd of=test.img"
Current result:
----------------
running time of save guest is more than 450s
Expected result:
----------------
running time of save guest is less than 450s
Basic root-causing log:
----------------------
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