From: Dave Hansen <dave.hansen@intel.com>
To: Uros Bizjak <ubizjak@gmail.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86/ioperm: Use atomic64_inc_return() in ksys_ioperm()
Date: Thu, 24 Oct 2024 08:20:57 -0700 [thread overview]
Message-ID: <be62f9c4-eca2-46bb-b566-77c0cbe1f15b@intel.com> (raw)
In-Reply-To: <20241007083345.47215-1-ubizjak@gmail.com>
On 10/7/24 01:33, Uros Bizjak wrote:
> Use atomic64_inc_return(&ref) instead of atomic64_add_return(1, &ref)
> to use optimized implementation and ease register pressure around
> the primitive for targets that implement optimized variant.
Ease register pressure at the end of a syscall?
I'll accept that we're doing this just as a matter of hygiene. But it's
a stretch to say there are any performance concerns whatsoever at the
end of the ioperm() syscall.
So what is the real reason for this patch?
next prev parent reply other threads:[~2024-10-24 15:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-07 8:33 [PATCH] x86/ioperm: Use atomic64_inc_return() in ksys_ioperm() Uros Bizjak
2024-10-24 15:20 ` Dave Hansen [this message]
2024-10-24 16:20 ` Uros Bizjak
2024-10-25 17:12 ` H. Peter Anvin
2024-10-25 21:01 ` Uros Bizjak
2024-10-26 23:28 ` H. Peter Anvin
2024-10-26 23:38 ` H. Peter Anvin
2024-10-27 1:23 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2024-10-24 18:27 Uros Bizjak
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