Re: question about fuse_disable_pagecache

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>>
>>both keep_cache and direct_io options control kernel page cache. 
>>'keep_cache = 1' means kernel does not invalidate inode's page cache 
>>on open(2).

Ok, Got it !


>>option 'client_oc' controls if fuse cache is enabled 

oh, didn't known that is was also also for fuse client.

Thanks !


Regards,

Alexandre
----- Mail original -----
De: "Yan, Zheng" <ukernel@xxxxxxxxx>
À: "aderumier" <aderumier@xxxxxxxxx>
Cc: "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx>
Envoyé: Mardi 6 Février 2018 06:15:18
Objet: Re: question about fuse_disable_pagecache

both keep_cache and direct_io options control kernel page cache. 
'keep_cache = 1' means kernel does not invalidate inode's page cache 
on open(2). option 'client_oc' controls if fuse cache is enabled 

On Tue, Feb 6, 2018 at 12:55 PM, Alexandre DERUMIER <aderumier@xxxxxxxxx> wrote: 
> Hi, 
> 
> I have a question about this commit 
> 
> https://github.com/ceph/ceph/pull/5521/commits/0f11ec237d4692d313a038ed61aa07a3f40555ba#diff-bf87beacb5e3b3ff3ade7ac4a8332d20 
> 
> which introduce "fuse_disable_pagecache" option 
> 
> commit description is 
> "In ceph-fuse case, 
> there are two caches, one is in ceph-fuse, another one is in kernel. 
> We can't disable/enable the kernel cache dynamically. So adding an 
> config option to completely disable kernel cache." 
> 
> and 
> 
> - if (cfuse->client->cct->_conf->fuse_use_invalidate_cb) 
> - fi->keep_cache = 1; 
> 
> +#if FUSE_VERSION >= FUSE_MAKE_VERSION(2, 8) 
> + if (cfuse->client->cct->_conf->fuse_disable_pagecache) 
> + fi->direct_io = 1; 
> + else if (cfuse->client->cct->_conf->fuse_use_invalidate_cb) 
> + fi->keep_cache = 1; 
> +#endif 
> 
> 
> So, does it disable both caches ? (fuse cache(keep_cache=0) and host cache (direct_io=1). 
> 
> Isn't it possible to have direct_io = 0 and keep_cache = 1 at the same time ? 
> 
> If I understand, fuse_use_invalidate_cb is to be able to invalidate fuse cache. 
> 
> Regards, 
> 
> Alexandre. 
> 
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