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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andi Kleen <ak@linux.intel.com>,
	Andrew Lutomirski <luto@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Brian Gerst <brgerst@gmail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [RFC v2 PATCH 6/7] x86/entry: get rid of ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS
Date: Thu, 8 Feb 2018 09:39:31 -0800	[thread overview]
Message-ID: <CA+55aFwWDfzgfiJNQCZkrOd8uUXp13TupPhNYrKSeeXMY-dr2g@mail.gmail.com> (raw)
In-Reply-To: <20180208094710.qnjixhm6hybebdv7@gmail.com>

On Thu, Feb 8, 2018 at 1:47 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> So for those reasons I'm really tempted by the all around simplification offered
> by this series:
>
>    2 files changed, 62 insertions(+), 160 deletions(-)
>
> Basically in this specific case I'd like to turn the argument around,
> use this simpler design and put the burden of proof on the patches that
> want to _complicate it_ beyond this simple, straightforward model

You make a good argument.

If the only real downside is slightly bigger static footprint (but the
actual real dynamic I$ footprint is not really impacted), then let's
just go for the simpler code.

It really would be lovely if our entry asm was understandable to mere mortals.

               Linus

  reply	other threads:[~2018-02-08 17:39 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-07 20:15 [RFC v2 PATCH 0/7] x86/entry: simplify and unify SAVE/POP_REGS Dominik Brodowski
2018-02-07 20:15 ` [RFC v2 PATCH 1/7] x86/entry: merge SAVE_C_REGS and SAVE_EXTRA_REGS, remove unused extensions Dominik Brodowski
2018-02-07 20:15 ` [RFC v2 PATCH 2/7] x86/entry: merge POP_C_REGS and POP_EXTRA_REGS Dominik Brodowski
2018-02-07 20:15 ` [RFC v2 PATCH 3/7] x86/entry: interleave XOR register clearing with PUSH instructions Dominik Brodowski
2018-02-07 20:15 ` [RFC v2 PATCH 4/7] x86/entry: introduce PUSH_AND_CLEAN_REGS Dominik Brodowski
2018-02-07 20:15 ` [RFC v2 PATCH 5/7] x86/entry: use PUSH_AND_CLEAN_REGS in more cases Dominik Brodowski
2018-02-07 20:15 ` [RFC v2 PATCH 6/7] x86/entry: get rid of ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS Dominik Brodowski
2018-02-07 20:44   ` Linus Torvalds
2018-02-07 21:29     ` Dominik Brodowski
2018-02-07 21:58       ` Linus Torvalds
2018-02-08  7:20         ` Dominik Brodowski
2018-02-08  9:47       ` Ingo Molnar
2018-02-08 17:39         ` Linus Torvalds [this message]
2018-02-08 18:35       ` Josh Poimboeuf
2018-02-07 20:15 ` [RFC v2 PATCH 7/7] x86/entry: indent PUSH_AND_CLEAR_REGS and POP_REGS properly Dominik Brodowski

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