Re: [PATCH V5] Allow compaction of unevictable pages

[Vlastimil Babka]

On 03/16/2015 02:49 PM, Eric B Munson wrote:
> On Mon, 16 Mar 2015, Vlastimil Babka wrote:
>
> > [CC += linux-api@]
> >
> > Since this is a kernel-user-space API change, please CC linux-api@.
> > The kernel source file Documentation/SubmitChecklist notes that all
> > Linux kernel patches that change userspace interfaces should be CCed
> > to linux-api@xxxxxxxxxxxxxxx, so that the various parties who are
> > interested in API changes are informed. For further information, see
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.kernel.org_doc_man-2Dpages_linux-2Dapi-2Dml.html&d=AwIC-g&c=96ZbZZcaMF4w0F4jpN6LZg&r=aUmMDRRT0nx4IfILbQLv8xzE0wB9sQxTHI3QrQ2lkBU&m=GUotTNnv26L0HxtXrBgiHqu6kwW3ufx2_TQpXIA216c&s=IFFYQ7Zr-4SIaF3slOZqiSP_noyva42kCwVRxxDm5wo&e=
>
> Added to the Cc list, thanks.
>
> > On 03/13/2015 09:19 PM, Michal Hocko wrote:
> > > On Fri 13-03-15 15:09:15, Eric B Munson wrote:
> > > > On Fri, 13 Mar 2015, Rik van Riel wrote:
> > > >
> > > > > On 03/13/2015 01:26 PM, Eric B Munson wrote:
> > > > >
> > > > > > --- a/mm/compaction.c
> > > > > > +++ b/mm/compaction.c
> > > > > > @@ -1046,6 +1046,8 @@ typedef enum {
> > > > > >   	ISOLATE_SUCCESS,	/* Pages isolated, migrate */
> > > > > >   } isolate_migrate_t;
> > > > > >
> > > > > > +int sysctl_compact_unevictable;
> >
> > A comment here would be useful I think, as well as explicit default
> > value. Maybe also __read_mostly although I don't know how much that
> > matters.
>
> I am going to sit on V6 for a couple of days incase anyone from rt wants
> to chime in.  But these will be in V6.
>
> > I also wonder if it might be confusing that "compact_memory" is a
> > write-only trigger that doesn't even show under "sysctl -a", while
> > "compact_unevictable" is a read/write setting. But I don't have a
> > better suggestion right now.
>
> Does allow_unevictable_compaction sound better?  It feels too much like

For sorting purposes, maybe compact_unevictable_allowed?

> variable naming conventions from other languages which seems to
> encourage verbosity to me, but does indicate a difference from
> compact_memory.

If it sounds too awkward/long and nobody else has better suggestion, 
then just keep it as "compact_unevictable".

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/