[pve-devel] QEMU LIve Migration - swap_free: Bad swap file entry

[Alexandre DERUMIER]

>>PS: all my guests do not even have !!SWAP!! 

Not sure is related to swap file.

I found an similar problem here, triggered with suspend/resume on ext4

http://lkml.indiana.edu/hypermail/linux/kernel/1106.3/01340.html


Maybe is it a guest kernel bug ?

----- Mail original ----- 

De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com, "qemu-devel" <qemu-devel at nongnu.org> 
Envoyé: Jeudi 6 Février 2014 12:19:36 
Objet: Re: [pve-devel] QEMU LIve Migration - swap_free: Bad swap file entry 


Am 06.02.2014 12:14, schrieb Alexandre DERUMIER: 
> Do you force rbd_cache=true in ceph.conf? 

no 

> if yes, do you use cache=writeback ? 

yes 

So this should be safe. 

PS: all my guests do not even have !!SWAP!! 

# free|grep Swap 
Swap: 0 0 0 

Stefan 

> according to ceph doc: 
> http://ceph.com/docs/next/rbd/qemu-rbd/ 
> 
> "Important If you set rbd_cache=true, you must set cache=writeback or risk data loss. Without cache=writeback, QEMU will not send flush requests to librbd. If QEMU exits uncleanly in this configuration, filesystems on top of rbd can be corrupted." 
> 
> 
> 
> ----- Mail original ----- 
> 
> De: "Stefan Priebe" <s.priebe at profihost.ag> 
> À: pve-devel at pve.proxmox.com, "qemu-devel" <qemu-devel at nongnu.org> 
> Envoyé: Mercredi 5 Février 2014 18:51:15 
> Objet: [pve-devel] QEMU LIve Migration - swap_free: Bad swap file entry 
> 
> Hello, 
> 
> after live migrating machines with a lot of memory (32GB, 48GB, ...) i 
> see pretty often crashing services after migration and the guest kernel 
> prints: 
> 
> [1707620.031806] swap_free: Bad swap file entry 00377410 
> [1707620.031806] swap_free: Bad swap file entry 00593c48 
> [1707620.031807] swap_free: Bad swap file entry 03201430 
> [1707620.031807] swap_free: Bad swap file entry 01bc5900 
> [1707620.031807] swap_free: Bad swap file entry 0173ce40 
> [1707620.031808] swap_free: Bad swap file entry 011c0270 
> [1707620.031808] swap_free: Bad swap file entry 03c58ae8 
> [1707660.749059] BUG: Bad rss-counter state mm:ffff88064d09f380 idx:1 
> val:1536 
> [1707660.749937] BUG: Bad rss-counter state mm:ffff88064d09f380 idx:2 
> val:-1536 
> 
> Qemu is 1.7 
> 
> Does anybody know a fix? 
> 
> Greets, 
> Stefan 
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