[Gluster-devel] Huge memory consumption with quota-marker

[Raghavendra Gowdappa]

----- Original Message -----
> From: "Krishnan Parthasarathi" <kparthas at redhat.com>
> To: "Pranith Kumar Karampuri" <pkarampu at redhat.com>
> Cc: "Vijay Bellur" <vbellur at redhat.com>, "Vijaikumar M" <vmallika at redhat.com>, "Gluster Devel"
> <gluster-devel at gluster.org>, "Raghavendra Gowdappa" <rgowdapp at redhat.com>, "Nagaprasad Sathyanarayana"
> <nsathyan at redhat.com>
> Sent: Thursday, July 2, 2015 10:54:44 AM
> Subject: Re: Huge memory consumption with quota-marker
> 
> Yes, we could take synctask size as an argument for synctask_create.
> The increase in synctask threads is not really a problem, it can't
> grow more than 16 (SYNCENV_PROC_MAX).

That is it cannot grow more than PROC_MAX in _single_ syncenv I suppose.

> 
> ----- Original Message -----
> > 
> > 
> > On 07/02/2015 10:40 AM, Krishnan Parthasarathi wrote:
> > >
> > > ----- Original Message -----
> > >> On Wednesday 01 July 2015 08:41 AM, Vijaikumar M wrote:
> > >>> Hi,
> > >>>
> > >>> The new marker xlator uses syncop framework to update quota-size in the
> > >>> background, it uses one synctask per write FOP.
> > >>> If there are 100 parallel writes with all different inodes but on the
> > >>> same directory '/dir', there will be ~100 txn waiting in queue to
> > >>> acquire a lock on on its parent i.e '/dir'.
> > >>> Each of this txn uses a syntack and each synctask allocates stack size
> > >>> of 2M (default size), so total 0f 200M usage. This usage can increase
> > >>> depending on the load.
> > >>>
> > >>> I am think of of using the stacksize for synctask to 256k, will this
> > >>> mem
> > >>> be sufficient as we perform very limited operations within a synctask
> > >>> in
> > >>> marker updation?
> > >>>
> > >> Seems like a good idea to me. Do we need a 256k stacksize or can we live
> > >> with something even smaller?
> > > It was 16K when synctask was introduced. This is a property of syncenv.
> > > We
> > > could
> > > create a separate syncenv for marker transactions which has smaller
> > > stacks.
> > > env->stacksize (and SYNCTASK_DEFAULT_STACKSIZE) was increased to 2MB to
> > > support
> > > pump xlator based data migration for replace-brick. For the no. of stack
> > > frames
> > > a marker transaction could use at any given time, we could use much
> > > lesser,
> > > 16K say.
> > > Does that make sense?
> > Creating one more syncenv will lead to extra sync-threads, may be we can
> > take stacksize as argument.
> > 
> > Pranith
> > 
>