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From: Ira Weiny <ira.weiny@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Fenghua Yu <fenghua.yu@intel.com>,
	linux-doc@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	Dan Williams <dan.j.williams@intel.com>,
	Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH V3 05/10] x86/entry: Pass irqentry_state_t by reference
Date: Mon, 16 Nov 2020 10:49:16 -0800	[thread overview]
Message-ID: <20201116184916.GA722447@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <87mtzi8n0z.fsf@nanos.tec.linutronix.de>

On Sun, Nov 15, 2020 at 07:58:52PM +0100, Thomas Gleixner wrote:
> Ira,
> 
> On Fri, Nov 06 2020 at 15:29, ira weiny wrote:
> 
> Subject prefix wants to 'entry:'. This changes generic code and the x86
> part is just required to fix the generic code change.

Sorry, yes that was carried incorrectly from earlier versions.

> 
> > Currently struct irqentry_state_t only contains a single bool value
> > which makes passing it by value is reasonable.  However, future patches
> > propose to add information to this struct, for example the PKRS
> > register/thread state.
> >
> > Adding information to irqentry_state_t makes passing by value less
> > efficient.  Therefore, change the entry/exit calls to pass irq_state by
> > reference.
> 
> The PKRS muck needs to add an u32 to that struct. So how is that a
> problem?

There are more fields to be added for the kmap/pmem support.  So this will be
needed eventually.  Even though it is not strictly necessary in the next patch.

> 
> The resulting struct still fits into 64bit which is by far more
> efficiently passed by value than by reference. So which problem are you
> solving here?

I'm getting ahead of myself a bit.  I will be adding more fields for the
kmap/pmem tracking.

Would you accept just a clean up for the variable names in this patch?  I could
then add the pass by reference when I add the new fields later.  Or would an
update to the commit message be ok to land this now?

Ira

> 
> Thanks
> 
>         tglx
> 

  reply	other threads:[~2020-11-16 18:49 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-06 23:28 [PATCH V3 00/10] PKS: Add Protection Keys Supervisor (PKS) support V3 ira.weiny
2020-11-06 23:28 ` [PATCH V3 01/10] x86/pkeys: Create pkeys_common.h ira.weiny
2020-11-06 23:29 ` [PATCH V3 02/10] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-11-06 23:29 ` [PATCH V3 03/10] x86/pks: Add PKS defines and Kconfig options ira.weiny
2020-11-06 23:29 ` [PATCH V3 04/10] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-12-17 14:50   ` Thomas Gleixner
2020-12-17 22:43     ` Thomas Gleixner
2020-12-18 13:57       ` Thomas Gleixner
2020-12-18 19:20         ` Dan Williams
2020-12-18 21:06           ` Thomas Gleixner
2020-12-18 21:58             ` Dan Williams
2020-12-18 22:44               ` Thomas Gleixner
2020-12-18 19:42         ` Ira Weiny
2020-12-18 20:10           ` Dave Hansen
2020-12-18 21:30           ` Thomas Gleixner
2020-12-18  4:05     ` Ira Weiny
2020-12-17 20:41   ` [NEEDS-REVIEW] " Dave Hansen
2020-12-18  4:10     ` Ira Weiny
2020-12-18 15:33       ` Dave Hansen
2020-11-06 23:29 ` [PATCH V3 05/10] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-11-15 18:58   ` Thomas Gleixner
2020-11-16 18:49     ` Ira Weiny [this message]
2020-11-16 20:36       ` Thomas Gleixner
2020-11-24  6:09   ` [PATCH V3.1] entry: " ira.weiny
2020-12-11 22:14     ` Andy Lutomirski
2020-12-16  1:32       ` Ira Weiny
2020-12-16  2:09         ` Andy Lutomirski
2020-12-17  0:38           ` Ira Weiny
2020-12-17 13:07       ` Thomas Gleixner
2020-12-17 13:19         ` Peter Zijlstra
2020-12-17 15:35           ` Andy Lutomirski
2020-12-17 16:58     ` Thomas Gleixner
2020-11-06 23:29 ` [PATCH V3 06/10] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-12-17 15:28   ` Thomas Gleixner
2020-11-06 23:29 ` [PATCH V3 07/10] x86/fault: Report the PKRS state on fault ira.weiny
2020-11-06 23:29 ` [PATCH V3 08/10] x86/pks: Add PKS kernel API ira.weiny
2020-12-23 20:39   ` Randy Dunlap
2020-11-06 23:29 ` [PATCH V3 09/10] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-11-06 23:29 ` [PATCH V3 10/10] x86/pks: Add PKS test code ira.weiny
2020-12-17 20:55   ` Dave Hansen
2020-12-18  4:05     ` Ira Weiny
2020-12-18 16:59       ` Dan Williams
2020-12-07 22:14 ` [PATCH V3 00/10] PKS: Add Protection Keys Supervisor (PKS) support V3 Ira Weiny
2020-12-08 15:55   ` Thomas Gleixner
2020-12-08 17:22     ` Ira Weiny

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