linux-kernel - RE: [PATCH] riscv: Move call to init_cpu_topology() to later initialization stage

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Message-ID: <bfd9b5ad438d43c5b44efe5c2ebf5d2e@EXMBX161.cuchost.com>
Date:   Thu, 5 Jan 2023 01:45:57 +0000
From:   Leyfoon Tan <leyfoon.tan@...rfivetech.com>
To:     Conor Dooley <conor@...nel.org>
CC:     Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        "linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Ley Foon Tan <lftan.linux@...il.com>
Subject: RE: [PATCH] riscv: Move call to init_cpu_topology() to later
 initialization stage



> On Tue, Jan 03, 2023 at 11:53:16AM +0800, Ley Foon Tan wrote:
> > topology_parse_cpu_capacity() is failed to allocate memory with
> > kcalloc() after read "capacity-dmips-mhz" DT parameter in CPU DT
> > nodes. This
> > topology_parse_cpu_capacity() is called from init_cpu_topology(), move
> > call to init_cpu_topology() to later initialization  stage (after
> > memory allocation is available).
> >
> > Note, this refers to ARM64 implementation, call init_cpu_topology() in
> > smp_prepare_cpus().
> >
> > Tested on Qemu platform.
> 
> I'd like to suggest a change to the commit message:
> ```
> If "capacity-dmips-mhz" is present in a CPU DT node,
> topology_parse_cpu_capacity() will fail to allocate memory.
> arm64, with which this code path is shared, does not call
> topology_parse_cpu_capacity() until later in boot where memory allocation
> is available.
> While "capacity-dmips-mhz" is not yet a valid property on RISC-V, invalid
> properties should be ignored rather than cause issues.
> Move init_cpu_topology(), which calls topology_parse_cpu_capacity(), to a
> later initialization stage, to match arm64.
> 
> As a side effect of this change, RISC-V is "protected" from changes to core
> topology code that would work on arm64 where memory allocation is safe
> but on RISC-V isn't.
> ```
> 
> You don't need to use exactly that, but with something along those
> lines:
> Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
> 
> Thanks,
> Conor.
Hi Conor

Thanks for your suggestions. Will send the v2 and update the commit message.

Regards
Ley Foon