From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Yury Norov <yury.norov@gmail.com>,
David Laight <David.Laight@aculab.com>
Cc: "'Alexei Starovoitov'" <alexei.starovoitov@gmail.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Joe Perches" <joe@perches.com>,
"Julia Lawall" <Julia.Lawall@inria.fr>,
"Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Nicolas Palix" <nicolas.palix@imag.fr>,
"Peter Zijlstra" <peterz@infradead.org>,
"Matti Vaittinen" <Matti.Vaittinen@fi.rohmeurope.com>,
LKML <linux-kernel@vger.kernel.org>,
"Alexei Starovoitov" <ast@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Chris Zankel" <chris@zankel.net>,
"Christophe Leroy" <christophe.leroy@csgroup.eu>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
"Max Filippov" <jcmvbkbc@gmail.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"linux-xtensa@linux-xtensa.org" <linux-xtensa@linux-xtensa.org>
Subject: Re: [PATCH 08/22] bitops: introduce MANY_BITS() macro
Date: Wed, 11 May 2022 12:59:13 +0200 [thread overview]
Message-ID: <9682c6f3-bc48-9ad1-4011-dfe1532e7491@rasmusvillemoes.dk> (raw)
In-Reply-To: <Ynq43wlPezrRzur8@yury-laptop>
On 10/05/2022 21.11, Yury Norov wrote:
> Another thing is that despite __attribute__(const), gcc sometimes doesn't
> recognize it as constant expression,
An ICE, Integer Constant Expression, is a C language thing.
__attribute__(const) has nothing to do with that, and no use of that
attribute is ever gonna convince gcc to treat an expression containing a
function call as an ICE [C++ is of course a whole different story].
The __attribute__(const) on a static inline function is utterly
pointless, the compiler can certainly see for itself that the function
has no side effects and that the expression can be CSE'ed.
All that aside, please drop that MANY_BITS thing. It will not make any
code any easier to read (MANY, is that four or five? or is it "more than
half the bit width"?). The n&(n-1) pattern is a well-known idiom, I
expect anybody hacking on an OS kernel to recognize
Rasmus
next prev parent reply other threads:[~2022-05-11 10:59 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-10 15:47 [PATCH 00/21] add coccinelle scripts for {bitmap,cpumask,nodes}_empty() Yury Norov
2022-05-10 15:47 ` [PATCH 01/22] introduce bitmap.cocci Yury Norov
2022-05-10 15:47 ` [cocci] " Yury Norov
2022-05-10 15:47 ` [PATCH 02/22] introduce cpumask.cocci Yury Norov
2022-05-10 15:47 ` [cocci] " Yury Norov
2022-05-10 15:47 ` [PATCH 03/22] introduce nodemask.cocci Yury Norov
2022-05-10 15:47 ` [cocci] " Yury Norov
2022-05-10 15:47 ` [PATCH 04/22] ice: use bitmap_empty() in ice_vf_has_no_qs_ena() Yury Norov
2022-05-10 15:47 ` [Intel-wired-lan] " Yury Norov
2022-05-10 15:47 ` [PATCH 05/22] iio: replace bitmap_weight with bitmap_weitght_{eq,le} where appropriate Yury Norov
2022-05-14 15:53 ` Jonathan Cameron
2022-05-14 16:31 ` Joe Perches
2022-05-15 16:40 ` Jonathan Cameron
2022-05-10 15:47 ` [PATCH 06/22] octeontx2: use bitmap_empty() instead of bitmap_weight() Yury Norov
2022-05-10 21:31 ` Jakub Kicinski
2022-05-10 15:47 ` [PATCH 07/22] risc-v: replace bitmap_weight with bitmap_empty in riscv_fill_hwcap() Yury Norov
2022-05-10 15:47 ` Yury Norov
2022-05-10 16:31 ` Anup Patel
2022-05-10 16:31 ` Anup Patel
2022-05-10 15:47 ` [PATCH 08/22] bitops: introduce MANY_BITS() macro Yury Norov
2022-05-10 16:50 ` Alexei Starovoitov
2022-05-10 17:54 ` David Laight
2022-05-10 19:11 ` Yury Norov
2022-05-11 10:59 ` Rasmus Villemoes [this message]
2022-05-10 17:57 ` Max Filippov
2022-05-10 19:16 ` Yury Norov
2022-05-11 4:55 ` Max Filippov
2022-05-10 15:47 ` [PATCH 09/22] qed: replace bitmap_weight() with MANY_BITS() Yury Norov
2022-05-10 15:47 ` [PATCH 10/22] net/mlx5e: simplify mlx5e_set_fecparam() Yury Norov
2022-05-10 15:47 ` [PATCH 11/22] KVM: x86: hyper-v: replace bitmap_weight() with hweight64() Yury Norov
2022-05-16 13:08 ` Vitaly Kuznetsov
2022-05-22 14:53 ` Guenter Roeck
2022-05-22 17:39 ` Yury Norov
2022-05-10 15:47 ` [PATCH 12/22] ia64: cleanup remove_siblinginfo() Yury Norov
2022-05-10 15:47 ` Yury Norov
2022-05-10 22:33 ` Andrew Morton
2022-05-10 22:33 ` Andrew Morton
2022-05-10 15:47 ` [PATCH 13/22] x86: smp: move cpumask_weight() out of for-loop in remove_siblinginfo Yury Norov
2022-05-11 9:47 ` Thomas Gleixner
2022-05-10 15:47 ` [PATCH 14/22] x86: smp: use cpumask_weight_eq() " Yury Norov
2022-05-10 15:47 ` [PATCH 15/22] net/mlx5: use cpumask_weight_gt() in irq_pool_request_irq() Yury Norov
2022-05-10 15:47 ` [PATCH 16/22] x86/tsc: use cpumask_weight_gt() in loop_timeout() Yury Norov
2022-05-10 15:47 ` [PATCH 17/22] sched/core: fix opencoded cpumask_any_but() Yury Norov
2022-05-10 16:37 ` Peter Zijlstra
2022-05-10 17:21 ` Valentin Schneider
2022-05-10 15:47 ` [PATCH 18/22] sched/core: remove unneeded cpumask_weight() in sched_core_cpu_{starting,deactivate} Yury Norov
2022-05-10 15:47 ` [PATCH 19/22] sched/core: replace cpumask_weight() with cpumask_weight_eq() where appropriate Yury Norov
2022-05-10 15:47 ` [PATCH 20/22] sched/topology: " Yury Norov
2022-05-10 15:47 ` [PATCH 21/22] cpufreq: use cpumask_weight_gt() in policy_is_shared() Yury Norov
2022-05-11 3:16 ` Viresh Kumar
2022-05-10 15:47 ` [PATCH 22/22] clockevents: use cpumask_weight_eq() in tick_cleanup_dead_cpu() Yury Norov
2022-05-11 8:18 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9682c6f3-bc48-9ad1-4011-dfe1532e7491@rasmusvillemoes.dk \
--to=linux@rasmusvillemoes.dk \
--cc=David.Laight@aculab.com \
--cc=Julia.Lawall@inria.fr \
--cc=Matti.Vaittinen@fi.rohmeurope.com \
--cc=akpm@linux-foundation.org \
--cc=alexei.starovoitov@gmail.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=ast@kernel.org \
--cc=chris@zankel.net \
--cc=christophe.leroy@csgroup.eu \
--cc=ebiederm@xmission.com \
--cc=gregkh@linuxfoundation.org \
--cc=jcmvbkbc@gmail.com \
--cc=joe@perches.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-xtensa@linux-xtensa.org \
--cc=memxor@gmail.com \
--cc=mirq-linux@rere.qmqm.pl \
--cc=nicolas.palix@imag.fr \
--cc=npiggin@gmail.com \
--cc=peterz@infradead.org \
--cc=toke@redhat.com \
--cc=yury.norov@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.