Re: [Crash-utility] [PATCH v2] diskdump: Optimize the boot time

-----Original Message----- > On Mon, Apr 11, 2022 at 12:30 PM HAGIO KAZUHITO(萩尾 一仁) < k-hagio-ab(a)nec.com <mailto:k-hagio-ab@nec.com> > > wrote: > > > Hi Lianbo, > > -----Original Message----- > > diff --git a/defs.h b/defs.h > > index 81ac049..1e8360d 100644 > > --- a/defs.h > > +++ b/defs.h > > @@ -4531,6 +4531,26 @@ struct machine_specific { > > #define NUM_IN_BITMAP(bitmap, x) (bitmap[(x)/BITS_PER_LONG] & NUM_TO_BIT(x)) > > #define SET_BIT(bitmap, x) (bitmap[(x)/BITS_PER_LONG] |= NUM_TO_BIT(x)) > > > > +static inline unsigned int __const_hweight8(unsigned long w) > > +{ > > + return > > + (!!((w) & (1ULL << 0))) + > > + (!!((w) & (1ULL << 1))) + > > + (!!((w) & (1ULL << 2))) + > > + (!!((w) & (1ULL << 3))) + > > + (!!((w) & (1ULL << 4))) + > > + (!!((w) & (1ULL << 5))) + > > + (!!((w) & (1ULL << 6))) + > > + (!!((w) & (1ULL << 7))); > > +} > > + > > +#define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8)) > > +#define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16)) > > +#define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32)) > > + > > +#define hweight32(w) __const_hweight32(w) > > +#define hweight64(w) __const_hweight64(w) > > + > > > > > > > > No need to move the above code from sbitmap.c to defs.h, a simple way is to implement a new function > in > > sbitmap.c and add its definition in defs.h, that will > > be easy to call it in diskdump.c. For example: > > > > diff --git a/defs.h b/defs.h > > index 81ac0498dac7..0c5115e71f1c 100644 > > --- a/defs.h > > +++ b/defs.h > > @@ -5894,6 +5894,7 @@ typedef bool (*sbitmap_for_each_fn)(unsigned int idx, void *p); > > void sbitmap_for_each_set(const struct sbitmap_context *sc, > > sbitmap_for_each_fn fn, void *data); > > void sbitmap_context_load(ulong addr, struct sbitmap_context *sc); > > +unsigned long get_hweight64(unsigned long w); > > > > /* sbitmap_queue helpers */ > > typedef bool (*sbitmapq_for_each_fn)(unsigned int idx, ulong addr, void *p); > > diff --git a/sbitmap.c b/sbitmap.c > > index 286259f71d64..628cc00c0b6b 100644 > > --- a/sbitmap.c > > +++ b/sbitmap.c > > @@ -71,6 +71,11 @@ static inline unsigned int __const_hweight8(unsigned long w) > > > > #define BIT(nr) (1UL << (nr)) > > > > +unsigned long get_hweight64(unsigned long w) > > +{ > > + return hweight64(w); > > +} > > + > > static inline unsigned long min(unsigned long a, unsigned long b) > > { > > return (a < b) ? a : b; > > > > > > //diskdump.c > > ... > > dd->valid_pages[i] += get_hweight64(tmp); > > > > ... > > > > How about the above suggestions? Shijie and Kazu. > > Thanks for the suggestion, but personally I don't think it has more > benefits than moving them. What is the good point? > > > > It has fewer code changes. The bitmap operation can be maintained together > in the sbitmap.c and won't be scattered elsewhere. > > In the future, some new functions may be still extended for the bitmap operations in the sbitmap.c, that > will avoid adding more bitmap operations to defs.h. > > That's my concern. If that is not a problem, the v2 will be fine to me. :-) Thanks for the explanation, I see. I think that it's not a problem for now. Now at least the existing bitmap operations become common ones and they do not use values in the sbitmap.c, it's not suitable to maintain them there with a function to access. If new functions are extended, let's optimize them at that time.