Re: [PATCH 4/6] hugetlb: introduce alloc_nodemask_of_node

Lee Schermerhorn
2009-09-01T16:42:14Z

On Tue, 2009-09-01 at 15:49 +0100, Mel Gorman wrote:
> On Fri, Aug 28, 2009 at 12:03:38PM -0400, Lee Schermerhorn wrote:
> > [PATCH 4/6] - hugetlb: introduce alloc_nodemask_of_node()
> >
> > Against: 2.6.31-rc7-mmotm-090827-0057
> >
> > New in V5 of series
> >
> > Introduce nodemask macro to allocate a nodemask and
> > initialize it to contain a single node, using the macro
> > init_nodemask_of_node() factored out of the nodemask_of_node()
> > macro.
> >
> > alloc_nodemask_of_node() coded as a macro to avoid header
> > dependency hell.
> >
> > This will be used to construct the huge pages "nodes_allowed"
> > nodemask for a single node when a persistent huge page
> > pool page count is modified via a per node sysfs attribute.
> >
> > Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
> >
> > include/linux/nodemask.h | 20 ++++++++++++++++++--
> > 1 file changed, 18 insertions(+), 2 deletions(-)
> >
> > Index: linux-2.6.31-rc7-mmotm-090827-0057/include/linux/nodemask.h
> > ===================================================================
> > --- linux-2.6.31-rc7-mmotm-090827-0057.orig/include/linux/nodemask.h 2009-08-28 09:21:19.000000000 -0400
> > +++ linux-2.6.31-rc7-mmotm-090827-0057/include/linux/nodemask.h 2009-08-28 09:21:29.000000000 -0400
> > @@ -245,18 +245,34 @@ static inline int __next_node(int n, con
> > return min_t(int,MAX_NUMNODES,find_next_bit(srcp->bits, MAX_NUMNODES, n+1));
> > }
> >
> > +#define init_nodemask_of_nodes(mask, node) \
> > + nodes_clear(*(mask)); \
> > + node_set((node), *(mask));
> > +
>
> Is the done thing to either make this a static inline or else wrap it in
> a do { } while(0) ? The reasoning being that if this is used as part of an
> another statement (e.g. a for loop) that it'll actually compile instead of
> throw up weird error messages.

Right. I'll fix this [and signoff/review orders] next time [maybe last
time?]. It occurs to me that I can also use this for
huge_mpol_nodes_allowed(), so I'll move it up in the series and fix that
[which you've already ack'd]. I'll wait a bit to hear from David before
I respin.

Thanks,
Lee
>
> > #define nodemask_of_node(node) \
> > ({ \
> > typeof(_unused_nodemask_arg_) m; \
> > if (sizeof(m) == sizeof(unsigned long)) { \
> > m.bits[0] = 1UL<<(node); \
> > } else { \
> > - nodes_clear(m); \
> > - node_set((node), m); \
> > + init_nodemask_of_nodes(&m, (node)); \
> > } \
> > m; \
> > })
> >
> > +/*
> > + * returns pointer to kmalloc()'d nodemask initialized to contain the
> > + * specified node. Caller must free with kfree().
> > + */
> > +#define alloc_nodemask_of_node(node) \
> > +({ \
> > + typeof(_unused_nodemask_arg_) *nmp; \
> > + nmp = kmalloc(sizeof(*nmp), GFP_KERNEL); \
> > + if (nmp) \
> > + init_nodemask_of_nodes(nmp, (node)); \
> > + nmp; \
> > +})
> > +
>
> Otherwise, it looks ok.
>
> > #define first_unset_node(mask) __first_unset_node(&(mask))
> > static inline int __first_unset_node(const nodemask_t *maskp)
> > {
> >
>