Re: [Qemu-devel] [PATCH v3 1/2] bitmap: get last word mask from nr directly

From: Wei Yang <richard.weiyang@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: quintela@redhat.com, corentincj@iksaif.net, pl@kamp.de,
	qemu-devel@nongnu.org, peterx@redhat.com,
	Wei Yang <richard.weiyang@gmail.com>,
	Wei Yang <richardw.yang@linux.intel.com>,
	kraxel@redhat.com
Subject: Re: [Qemu-devel] [PATCH v3 1/2] bitmap: get last word mask from nr directly
Date: Mon, 22 Jul 2019 00:29:45 +0000	[thread overview]
Message-ID: <20190722002945.iur4iu4nxployiss@master> (raw)
In-Reply-To: <796ed0ca-ecd7-9f18-71fa-59b94c403cbc@redhat.com>

On Sun, Jul 21, 2019 at 07:27:14PM +0200, Paolo Bonzini wrote:
>On 21/07/19 02:33, Wei Yang wrote:
>> On Thu, Jul 18, 2019 at 09:04:55AM +0800, Wei Yang wrote:
>>> The value left in nr is the number of bits for the last word, which
>>> could be calculate the last word mask directly.
>>>
>>> Remove the unnecessary size.
>>>
>> 
>> May I ask why Patch 2 is picked up, but this one is not?
>
>Tests are always good to have, this cleanup will wait for 4.2 but it's
>in the queue.
>

Thanks :-)

>Paolo
>
>>> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
>>>
>>> ---
>>> v2: refine bitmap_set_atomic too, suggested from Peter
>>> ---
>>> util/bitmap.c | 9 +++------
>>> 1 file changed, 3 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/util/bitmap.c b/util/bitmap.c
>>> index 1753ff7f5b..5b15249796 100644
>>> --- a/util/bitmap.c
>>> +++ b/util/bitmap.c
>>> @@ -160,7 +160,6 @@ int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
>>> void bitmap_set(unsigned long *map, long start, long nr)
>>> {
>>>     unsigned long *p = map + BIT_WORD(start);
>>> -    const long size = start + nr;
>>>     int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
>>>     unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
>>>
>>> @@ -174,7 +173,7 @@ void bitmap_set(unsigned long *map, long start, long nr)
>>>         p++;
>>>     }
>>>     if (nr) {
>>> -        mask_to_set &= BITMAP_LAST_WORD_MASK(size);
>>> +        mask_to_set &= BITMAP_LAST_WORD_MASK(nr);
>>>         *p |= mask_to_set;
>>>     }
>>> }
>>> @@ -182,7 +181,6 @@ void bitmap_set(unsigned long *map, long start, long nr)
>>> void bitmap_set_atomic(unsigned long *map, long start, long nr)
>>> {
>>>     unsigned long *p = map + BIT_WORD(start);
>>> -    const long size = start + nr;
>>>     int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
>>>     unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
>>>
>>> @@ -208,7 +206,7 @@ void bitmap_set_atomic(unsigned long *map, long start, long nr)
>>>
>>>     /* Last word */
>>>     if (nr) {
>>> -        mask_to_set &= BITMAP_LAST_WORD_MASK(size);
>>> +        mask_to_set &= BITMAP_LAST_WORD_MASK(nr);
>>>         atomic_or(p, mask_to_set);
>>>     } else {
>>>         /* If we avoided the full barrier in atomic_or(), issue a
>>> @@ -221,7 +219,6 @@ void bitmap_set_atomic(unsigned long *map, long start, long nr)
>>> void bitmap_clear(unsigned long *map, long start, long nr)
>>> {
>>>     unsigned long *p = map + BIT_WORD(start);
>>> -    const long size = start + nr;
>>>     int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
>>>     unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
>>>
>>> @@ -235,7 +232,7 @@ void bitmap_clear(unsigned long *map, long start, long nr)
>>>         p++;
>>>     }
>>>     if (nr) {
>>> -        mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
>>> +        mask_to_clear &= BITMAP_LAST_WORD_MASK(nr);
>>>         *p &= ~mask_to_clear;
>>>     }
>>> }
>>> -- 
>>> 2.17.1
>>>
>> 

-- 
Wei Yang
Help you, Help me