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Date:   Thu, 11 Aug 2022 22:40:06 -0700
From:   Yury Norov <yury.norov@gmail.com>
To:     "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc:     linux-kernel@vger.kernel.org,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        linuxppc-dev@lists.ozlabs.org,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [RESEND PATCH 2/2] lib/nodemask: inline next_node_in() and
 node_random()
Message-ID: <YvXntrThK+A1DiPI@yury-laptop>
References: <20220723214537.2054208-1-yury.norov@gmail.com>
 <20220723214537.2054208-3-yury.norov@gmail.com>
 <87o7wqkpme.fsf@linux.ibm.com>
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On Fri, Aug 12, 2022 at 10:46:57AM +0530, Aneesh Kumar K.V wrote:
> Yury Norov <yury.norov@gmail.com> writes:
> 
> > The functions are pretty thin wrappers around find_bit engine, and
> > keeping them in c-file prevents compiler from small_const_nbits()
> > optimization, which must take place for all systems with MAX_NUMNODES
> > less than BITS_PER_LONG (default is 16 for me).
> >
> > Moving them to header file doesn't blow up the kernel size:
> > add/remove: 1/2 grow/shrink: 9/5 up/down: 968/-88 (880)
> >
> > CC: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> > Signed-off-by: Yury Norov <yury.norov@gmail.com>
> > ---
> >  MAINTAINERS              |  1 -
> >  include/linux/nodemask.h | 27 ++++++++++++++++++++++-----
> >  lib/Makefile             |  2 +-
> >  lib/nodemask.c           | 30 ------------------------------
> >  4 files changed, 23 insertions(+), 37 deletions(-)
> >  delete mode 100644 lib/nodemask.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 7c0b8f28aa25..19c8d0ef1177 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -3540,7 +3540,6 @@ F:	lib/bitmap.c
> >  F:	lib/cpumask.c
> >  F:	lib/find_bit.c
> >  F:	lib/find_bit_benchmark.c
> > -F:	lib/nodemask.c
> >  F:	lib/test_bitmap.c
> >  F:	tools/include/linux/bitmap.h
> >  F:	tools/include/linux/find.h
> > diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
> > index 0f233b76c9ce..48ebe4007955 100644
> > --- a/include/linux/nodemask.h
> > +++ b/include/linux/nodemask.h
> > @@ -94,6 +94,7 @@
> >  #include <linux/bitmap.h>
> >  #include <linux/minmax.h>
> >  #include <linux/numa.h>
> > +#include <linux/random.h>
> >  
> >  typedef struct { DECLARE_BITMAP(bits, MAX_NUMNODES); } nodemask_t;
> >  extern nodemask_t _unused_nodemask_arg_;
> > @@ -276,7 +277,14 @@ static inline unsigned int __next_node(int n, const nodemask_t *srcp)
> >   * the first node in src if needed.  Returns MAX_NUMNODES if src is empty.
> >   */
> >  #define next_node_in(n, src) __next_node_in((n), &(src))
> > -unsigned int __next_node_in(int node, const nodemask_t *srcp);
> > +static inline unsigned int __next_node_in(int node, const nodemask_t *srcp)
> > +{
> > +	unsigned int ret = __next_node(node, srcp);
> > +
> > +	if (ret == MAX_NUMNODES)
> > +		ret = __first_node(srcp);
> > +	return ret;
> > +}
> >  
> >  static inline void init_nodemask_of_node(nodemask_t *mask, int node)
> >  {
> > @@ -493,14 +501,23 @@ static inline int num_node_state(enum node_states state)
> >  
> >  #endif
> >  
> > +/*
> > + * Return the bit number of a random bit set in the nodemask.
> > + * (returns NUMA_NO_NODE if nodemask is empty)
> > + */
> > +static inline int node_random(const nodemask_t *maskp)
> > +{
> >  #if defined(CONFIG_NUMA) && (MAX_NUMNODES > 1)
> > -extern int node_random(const nodemask_t *maskp);
> > +	int w, bit = NUMA_NO_NODE;
> > +
> > +	w = nodes_weight(*maskp);
> > +	if (w)
> > +		bit = find_nth_bit(maskp->bits, MAX_NUMNODES, get_random_int() % w);
> > +	return bit;
> >  #else
> > -static inline int node_random(const nodemask_t *mask)
> > -{
> >  	return 0;
> > -}
> >  #endif
> > +}
> >  
> >  #define node_online_map 	node_states[N_ONLINE]
> >  #define node_possible_map 	node_states[N_POSSIBLE]
> > diff --git a/lib/Makefile b/lib/Makefile
> > index f99bf61f8bbc..731cea0342d1 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -33,7 +33,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
> >  	 flex_proportions.o ratelimit.o show_mem.o \
> >  	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
> >  	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
> > -	 nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o \
> > +	 nmi_backtrace.o win_minmax.o memcat_p.o \
> >  	 buildid.o
> >  
> >  lib-$(CONFIG_PRINTK) += dump_stack.o
> > diff --git a/lib/nodemask.c b/lib/nodemask.c
> > deleted file mode 100644
> > index 7dad4ce8ff59..000000000000
> > --- a/lib/nodemask.c
> > +++ /dev/null
> > @@ -1,30 +0,0 @@
> > -// SPDX-License-Identifier: GPL-2.0
> > -#include <linux/nodemask.h>
> > -#include <linux/module.h>
> > -#include <linux/random.h>
> > -
> > -unsigned int __next_node_in(int node, const nodemask_t *srcp)
> > -{
> > -	unsigned int ret = __next_node(node, srcp);
> > -
> > -	if (ret == MAX_NUMNODES)
> > -		ret = __first_node(srcp);
> > -	return ret;
> > -}
> > -EXPORT_SYMBOL(__next_node_in);
> > -
> > -#ifdef CONFIG_NUMA
> > -/*
> > - * Return the bit number of a random bit set in the nodemask.
> > - * (returns NUMA_NO_NODE if nodemask is empty)
> > - */
> > -int node_random(const nodemask_t *maskp)
> > -{
> > -	int w, bit = NUMA_NO_NODE;
> > -
> > -	w = nodes_weight(*maskp);
> > -	if (w)
> > -		bit = find_nth_bit(maskp->bits, MAX_NUMNODES, get_random_int() % w);
> > -	return bit;
> > -}
> > -#endif
> > -- 
> > 2.34.1
> 
> The patch that got merged (36d4b36b69590fed99356a4426c940a253a93800) still have lib/nodemask.c

Thanks Aneesh. I'll send a fix shortly.