Messages in this thread | | | Date | Sat, 30 Mar 2019 21:54:36 +0300 | From | Yury Norov <> | Subject | Re: PATCH 2/2] lib/bitmap.c: guard exotic bitmap functions by CONFIG_NUMA |
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Hi Rasmus!
> From: Rasmus Villemoes <linux@rasmusvillemoes.dk> > Sent: Saturday, March 30, 2019 12:53:51 AM > To: Rasmus Villemoes; Andrew Morton; Andy Shevchenko > Cc: Yury Norov; linux-kernel@vger.kernel.org > Subject: [PATCH 2/2] lib/bitmap.c: guard exotic bitmap functions by CONFIG_NUMA > > The bitmap_remap, _bitremap, _onto and _fold functions are only used, > via their node_ wrappers, in mm/mempolicy.c, which is only built for > CONFIG_NUMA. The helper bitmap_ord_to_pos used by these functions is > global, but its only external caller is node_random() in lib/nodemask.c, > which is also guarded by CONFIG_NUMA.
Nice catch. I think you should protect declaration of those functions in include/linux/bitmap.h as well.
I'm concerned about pollution of such a generic portion of code with subsystem-related #ifdefs. Would it make more sense to move numa-specific stuff to lib/bitmap_numa.c and include/linux/bitmap_numa.h (or *_nodemask.h, or whatever)?
Yury
> For !CONFIG_NUMA: > > add/remove: 0/6 grow/shrink: 0/0 up/down: 0/-621 (-621) > Function old new delta > bitmap_pos_to_ord 20 - -20 > bitmap_ord_to_pos 70 - -70 > bitmap_bitremap 81 - -81 > bitmap_fold 113 - -113 > bitmap_onto 123 - -123 > bitmap_remap 214 - -214 > Total: Before=4776, After=4155, chg -13.00% > > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > --- > lib/bitmap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/lib/bitmap.c b/lib/bitmap.c > index 66421f304f7d..3f3b8051f342 100644 > --- a/lib/bitmap.c > +++ b/lib/bitmap.c > @@ -649,6 +649,7 @@ int bitmap_parselist_user(const char __user *ubuf, > EXPORT_SYMBOL(bitmap_parselist_user); > > > +#ifdef CONFIG_NUMA > /** > * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap > * @buf: pointer to a bitmap > @@ -952,6 +953,7 @@ void bitmap_fold(unsigned long *dst, const unsigned long *orig, > for_each_set_bit(oldbit, orig, nbits) > set_bit(oldbit % sz, dst); > } > +#endif /* CONFIG_NUMA */ > > /* > * Common code for bitmap_*_region() routines. > -- > 2.20.1 >
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