[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [Xen-devel] [PATCH] Add RCU support into Xen - Repost


> -----Original Message-----
> From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx] 
> Sent: Friday, January 26, 2007 10:40 AM
> To: Santos, Jose Renato G; xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: Turner, Yoshio; Jose Renato Santos; G John Janakiraman
> Subject: Re: [Xen-devel] [PATCH] Add RCU support into Xen - Repost
> On 17/1/07 12:36 am, "Santos, Jose Renato G" 
> <joserenato.santos@xxxxxx>
> wrote:
> >   I am planning to submit the following additional patches, 
> after this 
> > one is accepted:
> Now done. C/s 13648. I ripped out a few more bits of the 
> Linux RCU implementation and moved the hooks in schedule.c to 
> a single hook in do_softirq(). I suspect there is a tradeoff 
> between timeliness of checking for pending work and building 
> up nice batches of RCU work but checking in
> do_softirq() shouldn't mean we're hitting the RCU variables too often.

  Yes, that should be fine. The overhead should be small if we are only
  checking if there is RCU work to do.

  Looking at your changes, I think there are a few more bits that we can
  remove of the Linux RCU implementation. I will prepare a patch
  for you with some cleanup later. But, for now I would like to focus
  on the patches that modify the domain list manipulation and
  find_domain_by_id()to use the new RCU functions.

  While doing that I noticed that you removed the definitions of
  "rcu_read_lock()" and "rcu_read_unlock()" from rcupdate.h.
  Although they are really NOPs I think it would be good if we use
  them in all RCU read critical sections, for code clarity
  and documentation (as linux does).
  Can we add those back?



> >     1) rename_find_domain.patch: Rename find_domain_by_id() to
> > get_domain_by_id()
> Also done, by sed. C/s 13649.
>  -- Keir
> >     2) add_find_domain.patch: Add new find_domain_by_id() function 
> > that uses RCU
> >     3) use_find_domain.patch: Replace invocations of
> > get_domain_by_id()/put_domain() by find_domain_by_id() 
> where possible.

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.