From: Masahiro Yamada <masahiroy@kernel.org>
To: Yoann Congal <yoann.congal@smile.fr>
Cc: linux-fsdevel@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
x86@kernel.org, "André Almeida" <andrealmeid@igalia.com>,
"Borislav Petkov" <bp@alien8.de>,
"Darren Hart" <dvhart@infradead.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Davidlohr Bueso" <dave@stgolabs.net>,
"Geert Uytterhoeven" <geert@linux-m68k.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"H . Peter Anvin" <hpa@zytor.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Jiri Slaby" <jirislaby@kernel.org>,
"John Ogness" <john.ogness@linutronix.de>,
"Josh Triplett" <josh@joshtriplett.org>,
"Matthew Wilcox" <willy@infradead.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Petr Mladek" <pmladek@suse.com>,
"Sergey Senozhatsky" <senozhatsky@chromium.org>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Vegard Nossum" <vegard.nossum@oracle.com>
Subject: Re: [PATCH v5 1/3] printk: Fix LOG_CPU_MAX_BUF_SHIFT when BASE_SMALL is enabled
Date: Thu, 15 Feb 2024 06:36:50 +0900 [thread overview]
Message-ID: <CAK7LNARJERFRF=EM3RKL5jMgLbq0H1Op7FSRLJaVjrcR_nv0NA@mail.gmail.com> (raw)
In-Reply-To: <d845be0d-d0e4-4494-9572-753102f3fa24@smile.fr>
On Tue, Feb 13, 2024 at 4:01 AM Yoann Congal <yoann.congal@smile.fr> wrote:
>
>
>
> Le 11/02/2024 à 00:41, Masahiro Yamada a écrit :
> > On Thu, Feb 8, 2024 at 2:10 AM Yoann Congal <yoann.congal@smile.fr> wrote:
> >>
> >> LOG_CPU_MAX_BUF_SHIFT default value depends on BASE_SMALL:
> >> config LOG_CPU_MAX_BUF_SHIFT
> >> default 12 if !BASE_SMALL
> >> default 0 if BASE_SMALL
> >> But, BASE_SMALL is a config of type int and "!BASE_SMALL" is always
> >> evaluated to true whatever is the value of BASE_SMALL.
> >>
> >> This patch fixes this by using the correct conditional operator for int
> >> type : BASE_SMALL != 0.
> >>
> >> Note: This changes CONFIG_LOG_CPU_MAX_BUF_SHIFT=12 to
> >> CONFIG_LOG_CPU_MAX_BUF_SHIFT=0 for BASE_SMALL defconfigs, but that will
> >> not be a big impact due to this code in kernel/printk/printk.c:
> >> /* by default this will only continue through for large > 64 CPUs */
> >> if (cpu_extra <= __LOG_BUF_LEN / 2)
> >> return;
> >> Systems using CONFIG_BASE_SMALL and having 64+ CPUs should be quite
> >> rare.
> >>
> >> John Ogness <john.ogness@linutronix.de> (printk reviewer) wrote:
> >>> For printk this will mean that BASE_SMALL systems were probably
> >>> previously allocating/using the dynamic ringbuffer and now they will
> >>> just continue to use the static ringbuffer. Which is fine and saves
> >>> memory (as it should).
> >>
> >> Petr Mladek <pmladek@suse.com> (printk maintainer) wrote:
> >>> More precisely, it allocated the buffer dynamically when the sum
> >>> of per-CPU-extra space exceeded half of the default static ring
> >>> buffer. This happened for systems with more than 64 CPUs with
> >>> the default config values.
> >>
> >> Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
> >> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> >> Closes: https://lore.kernel.org/all/CAMuHMdWm6u1wX7efZQf=2XUAHascps76YQac6rdnQGhc8nop_Q@mail.gmail.com/
> >> Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
> >> Closes: https://lore.kernel.org/all/f6856be8-54b7-0fa0-1d17-39632bf29ada@oracle.com/
> >> Fixes: 4e244c10eab3 ("kconfig: remove unneeded symbol_empty variable")
> >>
> >
> >
> >
> > All the Reviewed-by tags are dropped every time, annoyingly.
>
> Hi!
>
> Was I supposed to gather these tags from patch version N to patch version N+1?
> In that case, I'm sorry, I did not know that :-/
> Patch 1/3 is exactly the same but patch 2/3 is equivalent but different. Is there a rule written somewhere about when carrying the tags across revision and when not? (I could not find it)
I do not know any written rules either.
In my experience, people carry tags
when changes since the previous version are small.
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2024-02-14 21:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 17:10 [PATCH v5 0/3] printk: CONFIG_BASE_SMALL fix for LOG_CPU_MAX_BUF_SHIFT and removal of CONFIG_BASE_FULL Yoann Congal
2024-02-07 17:10 ` [PATCH v5 1/3] printk: Fix LOG_CPU_MAX_BUF_SHIFT when BASE_SMALL is enabled Yoann Congal
2024-02-10 23:41 ` Masahiro Yamada
2024-02-12 19:01 ` Yoann Congal
2024-02-14 21:36 ` Masahiro Yamada [this message]
2024-02-07 17:10 ` [PATCH v5 2/3] printk: Change type of CONFIG_BASE_SMALL to bool Yoann Congal
2024-02-10 23:44 ` Masahiro Yamada
2024-02-07 17:10 ` [PATCH v5 3/3] printk: Remove redundant CONFIG_BASE_FULL Yoann Congal
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='CAK7LNARJERFRF=EM3RKL5jMgLbq0H1Op7FSRLJaVjrcR_nv0NA@mail.gmail.com' \
--to=masahiroy@kernel.org \
--cc=andrealmeid@igalia.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=dave@stgolabs.net \
--cc=dvhart@infradead.org \
--cc=geert@linux-m68k.org \
--cc=gregkh@linuxfoundation.org \
--cc=hpa@zytor.com \
--cc=jirislaby@kernel.org \
--cc=john.ogness@linutronix.de \
--cc=josh@joshtriplett.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pmladek@suse.com \
--cc=rostedt@goodmis.org \
--cc=senozhatsky@chromium.org \
--cc=tglx@linutronix.de \
--cc=vegard.nossum@oracle.com \
--cc=willemdebruijn.kernel@gmail.com \
--cc=willy@infradead.org \
--cc=x86@kernel.org \
--cc=yoann.congal@smile.fr \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).