linux-kernel - Re: [PATCH] kernel/entry: Remove some redundancy checks on syscall works

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Message-ID: <87frg2q1w7.ffs@tglx>
Date: Sat, 14 Jun 2025 08:21:28 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: Khalid Ali <khaliidcaliy@...il.com>, peterz@...radead.org, luto@...nel.org
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kernel/entry: Remove some redundancy checks on syscall
 works

Can you please reply to the mail you received, so that there are proper
In-Reply-To and References tags in the mail, which are required for mail
threading?

I almost missed your replies because they ended up as single mail
threads without reference somewhere in my endless mail pile.

On Fri, Jun 13 2025 at 20:28, Khalid Ali wrote:

> First if we are talking about performance then we may need likely() on
> SYSCALL_WORK_ENTER since the probability of condition evaluating as
> true is very high.

That depends on the system configuration scenario and the likely() has
been omitted on purpose.

> Second syscall_enter_audit() missing SYSCALL_WORK_SYSCALL_AUDIT
> evaluation, aren't we supposed to call it only if
> SYSCALL_WORK_SYSCALL_AUDIT is set?

That's redundant as syscall_enter_audit() checks for a valid audit
context already. Both are valid indicators and go in lockstep. So it
might be arguable that evaluating the work bit is cheaper than the
context check, but I doubt it's measurable.

Thanks,

        tglx