[pve-devel] disabling transparent hugepage by default like kernel 2.6.32 ?

[Alexandre DERUMIER]

>>Do you really want 'never'? I thought 'madvise' would be better, because we can
>>enable it
>>for some application (KVM)?

AFAIK, even jemalloc for example are not perfect with madvise , they are still latency impact.

They are a lot of bug report with transparent hudgepage with software like redis,varnish,mongodb,mysql,hadoop,oracle, event with madvise.


So I think it's better to setup to safe default value, "never".

User can still enable it after with "echo madvise|always > /sys/kernel/mm/transparent_hugepage/enabled"


----- Mail original -----
De: "dietmar" <dietmar at proxmox.com>
À: "aderumier" <aderumier at odiso.com>
Cc: "pve-devel" <pve-devel at pve.proxmox.com>
Envoyé: Mercredi 9 Septembre 2015 16:34:32
Objet: Re: [pve-devel] disabling transparent hugepage by default like kernel 2.6.32 ?

> >>I could set it in kernel config, for example: 
> >> 
> >>CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y 
> >> 
> >>would that help? 
> 
> Well, this is like "echo madvise > 
> /sys/kernel/mm/transparent_hugepage/enabled" 
> 
> But I don't see how to set never. 

Do you really want 'never'? I thought 'madvise' would be better, because we can 
enable it 
for some application (KVM)?