From: David Laight <david.laight.linux@gmail.com>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH -tip] x86/locking/atomic: Use asm_inline for atomic locking insns
Date: Wed, 5 Mar 2025 22:18:06 +0000 [thread overview]
Message-ID: <20250305221806.7f25108f@pumpkin> (raw)
In-Reply-To: <CAFULd4YNvz2rJEJDjacCeWak-JZNUfMB5LuM+qAwn_DCcn-CUg@mail.gmail.com>
On Wed, 5 Mar 2025 20:47:46 +0100
Uros Bizjak <ubizjak@gmail.com> wrote:
...
> From the compiler POV, now that "lock; " prefix lost its semicolon,
> removing LOCK_PREFIX_HERE or using asm_inline would result in exactly
> the same code. The problematic 31k code size increase (1.1%) with -O2
> is inevitable either way, if we want to move forward.
Have you looked to see where that 31k comes from?
The compiler must be very near to inlining something and removing a couple
of instructions is making a big difference.
It is quite likely that some other change will have the same (or the reverse)
effect.
David
next prev parent reply other threads:[~2025-03-05 22:18 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-28 12:35 [PATCH -tip] x86/locking/atomic: Use asm_inline for atomic locking insns Uros Bizjak
2025-02-28 13:13 ` Uros Bizjak
2025-02-28 16:48 ` Dave Hansen
2025-02-28 22:31 ` Uros Bizjak
2025-02-28 22:58 ` Dave Hansen
2025-03-01 9:05 ` Uros Bizjak
2025-03-01 12:38 ` Borislav Petkov
2025-03-05 8:54 ` Uros Bizjak
2025-03-05 17:04 ` Linus Torvalds
2025-03-05 19:40 ` Peter Zijlstra
2025-03-05 19:47 ` Uros Bizjak
2025-03-05 22:18 ` David Laight [this message]
2025-03-05 20:14 ` David Laight
2025-03-06 10:45 ` Uros Bizjak
2025-03-06 13:07 ` Uros Bizjak
2025-03-06 22:19 ` Ingo Molnar
2025-03-08 7:22 ` Uros Bizjak
2025-03-08 19:15 ` H. Peter Anvin
2025-03-05 19:55 ` Ingo Molnar
2025-03-05 20:13 ` Uros Bizjak
2025-03-05 20:21 ` Ingo Molnar
2025-03-06 9:38 ` Uros Bizjak
2025-03-05 20:20 ` Ingo Molnar
2025-03-06 10:52 ` Dirk Gouders
2025-03-06 10:59 ` Ingo Molnar
2025-03-05 20:36 ` Borislav Petkov
2025-03-05 21:26 ` Peter Zijlstra
2025-03-06 9:01 ` Uros Bizjak
2025-03-06 9:43 ` kernel: Current status of CONFIG_CC_OPTIMIZE_FOR_SIZE=y (was: Re: [PATCH -tip] x86/locking/atomic: Use asm_inline for atomic locking insns) Ingo Molnar
2025-03-06 10:37 ` Arnd Bergmann
2025-03-06 20:37 ` David Laight
2025-03-03 13:12 ` [PATCH -tip] x86/locking/atomic: Use asm_inline for atomic locking insns David Laight
2025-03-02 20:56 ` Uros Bizjak
2025-03-03 12:23 ` Uros Bizjak
2025-03-08 19:08 ` H. Peter Anvin
2025-03-09 7:50 ` Uros Bizjak
2025-03-09 9:46 ` David Laight
2025-03-09 9:57 ` Uros Bizjak
2025-03-06 9:57 ` Ingo Molnar
2025-03-06 10:26 ` Uros Bizjak
2025-03-06 10:38 ` Ingo Molnar
2025-03-06 10:50 ` Ingo Molnar
2025-03-06 13:56 ` Uros Bizjak
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