Howdy Kosaki-san,

Thanks for your time over this one :)

On Mon, May 20, 2013 at 08:55:33PM -0400, KOSAKI Motohiro wrote:
> (5/20/13 8:04 PM), Rafael Aquini wrote:
> > Intruduce a new flag to make page-cluster fine-grained discards while 
> > swapping
> > conditional, as they can be considered detrimental to some setups. However,
> > keep allowing batched discards at sys_swapon() time, when enabled by the
> > system administrator. 
> > 
> > Signed-off-by: Rafael Aquini <aqu...@redhat.com>
> > ---
> >  include/linux/swap.h |  8 +++++---
> >  mm/swapfile.c        | 12 ++++++++----
> >  2 files changed, 13 insertions(+), 7 deletions(-)
> > 
> > diff --git a/include/linux/swap.h b/include/linux/swap.h
> > index 1701ce4..ab2e742 100644
> > --- a/include/linux/swap.h
> > +++ b/include/linux/swap.h
> > @@ -19,10 +19,11 @@ struct bio;
> >  #define SWAP_FLAG_PREFER   0x8000  /* set if swap priority specified */
> >  #define SWAP_FLAG_PRIO_MASK        0x7fff
> >  #define SWAP_FLAG_PRIO_SHIFT       0
> > -#define SWAP_FLAG_DISCARD  0x10000 /* discard swap cluster after use */
> > +#define SWAP_FLAG_DISCARD  0x10000 /* enable discard for swap areas */
> > +#define SWAP_FLAG_DISCARD_CLUSTER 0x20000 /* discard swap clusters after 
> > use */
> 
> From point of backward compatibility view, 0x10000 should be disable both 
> discarding
> when mount and when IO.

I think you mean 0x10000 should be enable both here, then. That's a nice catch. 
I'll
try to think a way to accomplish it in a simple fashion.


> And, introducing new two flags, enable mount time discard and enable IO time 
> discard.
> 
> IOW, Please consider newer kernel and older swapon(8) conbination.
> Other than that, looks good to me.
> 
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to