linux-kernel - Re: [PATCH v3 0/3] Speed up boot with faster linear map creation

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Date: Wed, 10 Apr 2024 21:53:41 +0900
From: Itaru Kitayama <itaru.kitayama@...ux.dev>
To: Will Deacon <will@...nel.org>
Cc: Catalin Marinas <catalin.marinas@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ard Biesheuvel <ardb@...nel.org>,
	David Hildenbrand <david@...hat.com>,
	Donald Dutile <ddutile@...hat.com>,
	Eric Chanudet <echanude@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>, kernel-team@...roid.com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/3] Speed up boot with faster linear map creation

On Fri, Apr 12, 2024 at 05:06:41PM +0100, Will Deacon wrote:
> On Fri, 12 Apr 2024 14:19:05 +0100, Ryan Roberts wrote:
> > It turns out that creating the linear map can take a significant proportion of
> > the total boot time, especially when rodata=full. And most of the time is spent
> > waiting on superfluous tlb invalidation and memory barriers. This series reworks
> > the kernel pgtable generation code to significantly reduce the number of those
> > TLBIs, ISBs and DSBs. See each patch for details.
> > 
> > The below shows the execution time of map_mem() across a couple of different
> > systems with different RAM configurations. We measure after applying each patch
> > and show the improvement relative to base (v6.9-rc2):
> > 
> > [...]
> 
> Applied to arm64 (for-next/mm), thanks!
> 
> [1/3] arm64: mm: Don't remap pgtables per-cont(pte|pmd) block
>       https://git.kernel.org/arm64/c/5c63db59c5f8
> [2/3] arm64: mm: Batch dsb and isb when populating pgtables
>       https://git.kernel.org/arm64/c/1fcb7cea8a5f
> [3/3] arm64: mm: Don't remap pgtables for allocate vs populate
>       https://git.kernel.org/arm64/c/0e9df1c905d8

I confirm this series boots the system on FVP (with my .config and my
buildroot rootfs using Shrinkwrap).

Tested-by: Itaru Kitayama <itaru.kitayama@...itsu.com>

Thanks,
Itaru.

> 
> Cheers,
> -- 
> Will
> 
> https://fixes.arm64.dev
> https://next.arm64.dev
> https://will.arm64.dev