From: Yury Norov <yury.norov@gmail•com>
To: "Michał Mirosław" <mirq-linux@rere•qmqm.pl>
Cc: Juri Lelli <juri.lelli@redhat•com>, Andrew Lunn <andrew@lunn•ch>,
"Rafael J. Wysocki" <rafael@kernel•org>,
Catalin Marinas <catalin.marinas@arm•com>,
Guo Ren <guoren@kernel•org>, Christoph Lameter <cl@linux•com>,
Christoph Hellwig <hch@lst•de>, Andi Kleen <ak@linux•intel.com>,
Vincent Guittot <vincent.guittot@linaro•org>,
Ingo Molnar <mingo@redhat•com>,
Geert Uytterhoeven <geert@linux-m68k•org>,
Mel Gorman <mgorman@suse•de>,
Viresh Kumar <viresh.kumar@linaro•org>,
Petr Mladek <pmladek@suse•com>,
Arnaldo Carvalho de Melo <acme@kernel•org>,
Jens Axboe <axboe@fb•com>, Andy Lutomirski <luto@kernel•org>,
Lee Jones <lee.jones@linaro•org>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Randy Dunlap <rdunlap@infradead•org>,
linux-kernel@vger•kernel.org, linux-perf-users@vger•kernel.org,
Sergey Senozhatsky <senozhatsky@chromium•org>,
Thomas Gleixner <tglx@linutronix•de>,
linux-crypto@vger•kernel.org, Tejun Heo <tj@kernel•org>,
Andrew Morton <akpm@linux-foundation•org>,
Mark Rutland <mark.rutland@arm•com>,
Anup Patel <anup.patel@wdc•com>,
linux-ia64@vger•kernel.org, David Airlie <airlied@linux•ie>,
Roy Pledge <Roy.Pledge@nxp•com>,
Dave Hansen <dave.hansen@linux•intel.com>,
Solomon Peachy <pizza@shaftnet•org>,
Stephen Rothwell <sfr@canb•auug.org.au>,
Krzysztof Kozlowski <krzysztof.kozlowski@canonical•com>,
Dennis Zhou <dennis@kernel•org>,
Matti Vaittinen <mazziesaccount@gmail•com>,
linux-alpha@vger•kernel.org, Kalle Valo <kvalo@codeaurora•org>,
Stephen Boyd <sboyd@kernel•org>, Tariq Toukan <tariqt@nvidia•com>,
Dinh Nguyen <dinguyen@kernel•org>,
Jonathan Cameron <jic23@kernel•org>,
Ulf Hansson <ulf.hansson@linaro•org>,
Alexander Shishkin <alexander.shishkin@linux•intel.com>,
Mike Marciniszyn <mike.marciniszyn@cornelisnetworks•com>,
Rasmus Villemoes <linux@rasmusvillemoes•dk>,
Subbaraya Sundeep <sbhatta@marvell•com>,
Will Deacon <will@kernel•org>, Sagi Grimberg <sagi@grimberg•me>,
linux-csky@vger•kernel.org,
bcm-kernel-feedback-list@broadcom•com,
linux-arm-kernel@lists•infradead.org,
linux-snps-arc@lists•infradead.org,
Kees Cook <keescook@chromium•org>, Arnd Bergmann <arnd@arndb•de>,
"James E.J. Bottomley" <jejb@linux•ibm.com>,
Vineet Gupta <vgupta@kernel•org>,
Steven Rostedt <rostedt@goodmis•org>,
Mark Gross <markgross@kernel•org>, Borislav Petkov <bp@alien8•de>,
Mauro Carvalho Chehab <mchehab@kernel•org>,
Thomas Bogendoerfer <tsbogend@alpha•franken.de>,
"Martin K. Petersen" <martin.petersen@oracle•com>,
David Laight <David.Laight@aculab•com>,
Sudeep Holla <sudeep.holla@arm•com>,
Geetha sowjanya <gakula@marvell•com>,
Ian Rogers <irogers@google•com>,
kvm@vger•kernel.org, Peter Zijlstra <peterz@infradead•org>,
Amitkumar Karwar <amitkarwar@gmail•com>,
linux-mm@kvack•org, linux-riscv@lists•infradead.org,
Jiri Olsa <jolsa@redhat•com>, Ard Biesheuvel <ardb@kernel•org>,
Marc Zyngier <maz@kernel•org>,
Russell King <linux@armlinux•org.uk>,
Andy Gross <agross@kernel•org>, Jakub Kicinski <kuba@kernel•org>,
Vivien Didelot <vivien.didelot@gmail•com>,
Sunil Goutham <sgoutham@marvell•com>,
"Paul E. McKenney" <paulmck@kernel•org>,
linux-s390@vger•kernel.org, Alexey Klimov <aklimov@redhat•com>,
Heiko Carstens <hca@linux•ibm.com>,
Hans de Goede <hdegoede@redhat•com>,
Nicholas Piggin <npiggin@gmail•com>,
Marcin Wojtas <mw@semihalf•com>, Vlastimil Babka <vbabka@suse•cz>,
linuxppc-dev@lists•ozlabs.org, linux-mips@vger•kernel.org,
Palmer Dabbelt <palmer@dabbelt•com>,
Daniel Vetter <daniel@ffwll•ch>,
Jason Wessel <jason.wessel@windriver•com>,
Saeed Mahameed <saeedm@nvidia•com>,
Andy Shevchenko <andy@infradead•org>
Subject: Re: [PATCH 7/9] lib/cpumask: add num_{possible,present,active}_cpus_{eq,gt,le}
Date: Sat, 27 Nov 2021 22:34:47 -0800 [thread overview]
Message-ID: <20211128063447.GA270945@lapt> (raw)
In-Reply-To: <YaMME60Jfiz5BeJF@qmqm.qmqm.pl>
(restore CC list)
On Sun, Nov 28, 2021 at 05:56:51AM +0100, Michał Mirosław wrote:
> On Sat, Nov 27, 2021 at 07:57:02PM -0800, Yury Norov wrote:
> > Add num_{possible,present,active}_cpus_{eq,gt,le} and replace num_*_cpus()
> > with one of new functions where appropriate. This allows num_*_cpus_*()
> > to return earlier depending on the condition.
> [...]
> > @@ -3193,7 +3193,7 @@ int __init pcpu_page_first_chunk(size_t reserved_size,
> >
> > /* allocate pages */
> > j = 0;
> > - for (unit = 0; unit < num_possible_cpus(); unit++) {
> > + for (unit = 0; num_possible_cpus_gt(unit); unit++) {
>
> This looks dubious.
Only this?
> The old version I could hope the compiler would call
> num_possible_cpus() only once if it's marked const or pure, but the
> alternative is going to count the bits every time making this a guaranteed
> O(n^2) even though the bitmap doesn't change.
num_possible_cpus() is not const neither pure. This is O(n^2) before and after.
next prev parent reply other threads:[~2021-11-28 7:05 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 ` [PATCH 2/9] lib/bitmap: implement bitmap_{empty,full} " Michał Mirosław
2021-11-28 6:27 ` Yury Norov
2021-11-28 18:10 ` Michał Mirosław
2021-12-14 19:43 ` [PATCH 2/9] lib/bitmap: implement bitmap_{empty, full} " Yury Norov
2021-12-15 8:40 ` [PATCH 2/9] lib/bitmap: implement bitmap_{empty,full} " David Laight
2021-12-15 17:45 ` [PATCH 2/9] lib/bitmap: implement bitmap_{empty, full} " Yury Norov
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 ` [PATCH 3/9] all: replace bitmap_weigth() with bitmap_{empty,full,eq,gt,le} 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 ` [PATCH 7/9] lib/cpumask: add num_{possible,present,active}_cpus_{eq,gt,le} Michał Mirosław
2021-11-28 5:09 ` Michał Mirosław
2021-11-28 6:34 ` Yury Norov [this message]
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 ` [PATCH 7/9] lib/cpumask: add num_{possible, present, active}_cpus_{eq, gt, le} Emil Renner Berthing
2021-11-28 17:57 ` [PATCH 7/9] lib/cpumask: add num_{possible,present,active}_cpus_{eq,gt,le} 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 18:05 ` Michał Mirosław
2021-11-28 18:03 ` mirq-test
2021-11-29 6:38 ` Yury Norov
2021-11-29 16:34 ` Michał Mirosław
2021-12-02 0:31 ` Yury Norov
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=20211128063447.GA270945@lapt \
--to=yury.norov@gmail$(echo .)com \
--cc=David.Laight@aculab$(echo .)com \
--cc=Roy.Pledge@nxp$(echo .)com \
--cc=acme@kernel$(echo .)org \
--cc=agross@kernel$(echo .)org \
--cc=airlied@linux$(echo .)ie \
--cc=ak@linux$(echo .)intel.com \
--cc=aklimov@redhat$(echo .)com \
--cc=akpm@linux-foundation$(echo .)org \
--cc=alexander.shishkin@linux$(echo .)intel.com \
--cc=amitkarwar@gmail$(echo .)com \
--cc=andrew@lunn$(echo .)ch \
--cc=andy@infradead$(echo .)org \
--cc=anup.patel@wdc$(echo .)com \
--cc=ardb@kernel$(echo .)org \
--cc=arnd@arndb$(echo .)de \
--cc=axboe@fb$(echo .)com \
--cc=bcm-kernel-feedback-list@broadcom$(echo .)com \
--cc=bp@alien8$(echo .)de \
--cc=catalin.marinas@arm$(echo .)com \
--cc=cl@linux$(echo .)com \
--cc=daniel@ffwll$(echo .)ch \
--cc=dave.hansen@linux$(echo .)intel.com \
--cc=dennis@kernel$(echo .)org \
--cc=dinguyen@kernel$(echo .)org \
--cc=gakula@marvell$(echo .)com \
--cc=geert@linux-m68k$(echo .)org \
--cc=gregkh@linuxfoundation$(echo .)org \
--cc=guoren@kernel$(echo .)org \
--cc=hca@linux$(echo .)ibm.com \
--cc=hch@lst$(echo .)de \
--cc=hdegoede@redhat$(echo .)com \
--cc=irogers@google$(echo .)com \
--cc=jason.wessel@windriver$(echo .)com \
--cc=jejb@linux$(echo .)ibm.com \
--cc=jic23@kernel$(echo .)org \
--cc=jolsa@redhat$(echo .)com \
--cc=juri.lelli@redhat$(echo .)com \
--cc=keescook@chromium$(echo .)org \
--cc=krzysztof.kozlowski@canonical$(echo .)com \
--cc=kuba@kernel$(echo .)org \
--cc=kvalo@codeaurora$(echo .)org \
--cc=kvm@vger$(echo .)kernel.org \
--cc=lee.jones@linaro$(echo .)org \
--cc=linux-alpha@vger$(echo .)kernel.org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-crypto@vger$(echo .)kernel.org \
--cc=linux-csky@vger$(echo .)kernel.org \
--cc=linux-ia64@vger$(echo .)kernel.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-mips@vger$(echo .)kernel.org \
--cc=linux-mm@kvack$(echo .)org \
--cc=linux-perf-users@vger$(echo .)kernel.org \
--cc=linux-riscv@lists$(echo .)infradead.org \
--cc=linux-s390@vger$(echo .)kernel.org \
--cc=linux-snps-arc@lists$(echo .)infradead.org \
--cc=linux@armlinux$(echo .)org.uk \
--cc=linux@rasmusvillemoes$(echo .)dk \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=luto@kernel$(echo .)org \
--cc=mark.rutland@arm$(echo .)com \
--cc=markgross@kernel$(echo .)org \
--cc=martin.petersen@oracle$(echo .)com \
--cc=maz@kernel$(echo .)org \
--cc=mazziesaccount@gmail$(echo .)com \
--cc=mchehab@kernel$(echo .)org \
--cc=mgorman@suse$(echo .)de \
--cc=mike.marciniszyn@cornelisnetworks$(echo .)com \
--cc=mingo@redhat$(echo .)com \
--cc=mirq-linux@rere$(echo .)qmqm.pl \
--cc=mw@semihalf$(echo .)com \
--cc=npiggin@gmail$(echo .)com \
--cc=palmer@dabbelt$(echo .)com \
--cc=paulmck@kernel$(echo .)org \
--cc=peterz@infradead$(echo .)org \
--cc=pizza@shaftnet$(echo .)org \
--cc=pmladek@suse$(echo .)com \
--cc=rafael@kernel$(echo .)org \
--cc=rdunlap@infradead$(echo .)org \
--cc=rostedt@goodmis$(echo .)org \
--cc=saeedm@nvidia$(echo .)com \
--cc=sagi@grimberg$(echo .)me \
--cc=sbhatta@marvell$(echo .)com \
--cc=sboyd@kernel$(echo .)org \
--cc=senozhatsky@chromium$(echo .)org \
--cc=sfr@canb$(echo .)auug.org.au \
--cc=sgoutham@marvell$(echo .)com \
--cc=sudeep.holla@arm$(echo .)com \
--cc=tariqt@nvidia$(echo .)com \
--cc=tglx@linutronix$(echo .)de \
--cc=tj@kernel$(echo .)org \
--cc=tsbogend@alpha$(echo .)franken.de \
--cc=ulf.hansson@linaro$(echo .)org \
--cc=vbabka@suse$(echo .)cz \
--cc=vgupta@kernel$(echo .)org \
--cc=vincent.guittot@linaro$(echo .)org \
--cc=viresh.kumar@linaro$(echo .)org \
--cc=vivien.didelot@gmail$(echo .)com \
--cc=will@kernel$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox