From: Yury Norov <yury.norov@gmail.com>
To: David Laight <David.Laight@aculab.com>
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Subject: Re: [PATCH 2/9] lib/bitmap: implement bitmap_{empty,full} with bitmap_weight_eq()
Date: Wed, 15 Dec 2021 09:45:30 -0800 [thread overview]
Message-ID: <CAAH8bW-u5AsFTXUOJPRkF-6dk1LcL7PE0Tm+dUc9Ctb6JMy=tg@mail.gmail.com> (raw)
In-Reply-To: <0ccb827de1164b2989d652bfb6f1bbab@AcuMS.aculab.com>
On Wed, Dec 15, 2021 at 12:41 AM David Laight <David.Laight@aculab.com> wrote:
>
> From: Yury Norov
> > Sent: 14 December 2021 19:43
> ...
> >
> > I think that for long bitmaps the most time consuming operation is moving
> > data to L1, and for short bitmaps the difference between approaches is
> > barely measurable.
> >
> > But hweght_long on each iteration can't be more effective than the current
> > version. So, I'll drop this patch for v2 and keep things unchanged.
>
> Actually do bitmap_full/empty() calls make any sense at all?
> The result is stale since bitmaps are designed to do locked operations.
> If you have a lock covering the bitmap then you should be using
> something that uses non-locked accesses.
> Rightly or wrongly that isn't the bitmap api.
Are you talking about __{set,clear}_bit()?
include/asm-generic/bitops/non-atomic.h
next prev parent reply other threads:[~2021-12-15 17:45 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-28 3:56 [PATCH 0/9] lib/bitmap: optimize bitmap_weight() usage Yury Norov
2021-11-28 3:56 ` [PATCH 1/9] lib/bitmap: add bitmap_weight_{eq,gt,le} Yury Norov
2021-11-28 3:56 ` [PATCH 2/9] lib/bitmap: implement bitmap_{empty,full} with bitmap_weight_eq() Yury Norov
2021-11-28 4:37 ` Michał Mirosław
2021-11-28 6:27 ` Yury Norov
2021-11-28 18:10 ` Michał Mirosław
2021-12-14 19:43 ` Yury Norov
2021-12-15 8:40 ` David Laight
2021-12-15 17:45 ` Yury Norov [this message]
2021-11-28 3:56 ` [PATCH 3/9] all: replace bitmap_weigth() with bitmap_{empty,full,eq,gt,le} Yury Norov
2021-11-28 4:47 ` Michał Mirosław
2021-11-28 8:01 ` Greg Kroah-Hartman
2021-11-28 3:56 ` [PATCH 4/9] tools: sync bitmap_weight() usage with the kernel Yury Norov
2021-11-28 3:57 ` [PATCH 5/9] lib/cpumask: add cpumask_weight_{eq,gt,le} Yury Norov
2021-11-28 3:57 ` [PATCH 6/9] lib/nodemask: add nodemask_weight_{eq,gt,le} Yury Norov
2021-11-28 3:57 ` [PATCH 7/9] lib/cpumask: add num_{possible,present,active}_cpus_{eq,gt,le} Yury Norov
2021-11-28 4:56 ` Michał Mirosław
2021-11-28 5:09 ` Michał Mirosław
2021-11-28 6:34 ` Yury Norov
2021-11-28 17:07 ` Joe Perches
2021-11-28 17:43 ` Yury Norov
2021-11-28 17:54 ` Dennis Zhou
2021-11-28 18:47 ` Yury Norov
2021-11-28 17:56 ` Emil Renner Berthing
2021-11-28 17:57 ` Joe Perches
2021-11-28 3:57 ` [PATCH 8/9] lib/nodemask: add num_node_state_eq() Yury Norov
2021-11-28 3:57 ` [PATCH 9/9] MAINTAINERS: add cpumask and nodemask files to BITMAP_API Yury Norov
2021-11-28 11:08 ` [PATCH 0/9] lib/bitmap: optimize bitmap_weight() usage Nicholas Piggin
2021-11-28 23:36 ` Yury Norov
2021-11-28 18:03 ` mirq-test
2021-11-28 18:05 ` Michał Mirosław
2021-11-29 6:38 ` Yury Norov
2021-11-29 16:34 ` Michał Mirosław
2021-12-02 0:31 ` Yury Norov
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