From: Guo Ren <guoren@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Palmer Dabbelt" <palmer@rivosinc.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Peter Zijlstra" <peterz@infradead.org>,
"Andy Lutomirski" <luto@kernel.org>,
"Conor.Dooley" <conor.dooley@microchip.com>,
"Heiko Stübner" <heiko@sntech.de>,
"Jisheng Zhang" <jszhang@kernel.org>,
lazyparser@gmail.com, falcon@tinylab.org,
"Huacai Chen" <chenhuacai@kernel.org>,
"Anup Patel" <apatel@ventanamicro.com>,
"Atish Patra" <atishp@atishpatra.org>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
Linux-Arch <linux-arch@vger.kernel.org>,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
"Guo Ren" <guoren@linux.alibaba.com>,
"Andreas Schwab" <schwab@suse.de>
Subject: Re: [PATCH V4 8/8] riscv: Add config of thread stack size
Date: Mon, 19 Sep 2022 16:35:04 +0800 [thread overview]
Message-ID: <CAJF2gTRoKfJ25brnA=_CqNw9DPt8XKhcyNzmCbD6wX1q-jiR1w@mail.gmail.com> (raw)
In-Reply-To: <8817af55-de0d-4e8f-a41b-25d01d5fa968@www.fastmail.com>
On Sun, Sep 11, 2022 at 12:07 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Sat, Sep 10, 2022, at 2:52 PM, Guo Ren wrote:
> > On Thu, Sep 8, 2022 at 3:37 PM Arnd Bergmann <arnd@arndb.de> wrote:
> >> On Thu, Sep 8, 2022, at 4:25 AM, guoren@kernel.org wrote:
> >> > From: Guo Ren <guoren@linux.alibaba.com>
> >> - When VMAP_STACK is set, make it possible to select non-power-of-two
> >> stack sizes. Most importantly, 12KB should be a really interesting
> >> choice as 8KB is probably still not enough for many 64-bit workloads,
> >> but 16KB is often more than what you need. You probably don't
> >> want to allow 64BIT/8KB without VMAP_STACK anyway since that just
> >> makes it really hard to debug, so hiding the option when VMAP_STACK
> >> is disabled may also be a good idea.
> > I don't want this config to depend on VMAP_STACK. Some D1 chips would
> > run with an 8K stack size and !VMAP_STACK.
>
> That sounds like a really bad idea, why would you want to risk
> using such a small stack without CONFIG_VMAP_STACK?
>
> Are you worried about increased memory usage or something else?
>
> > /* thread information allocation */
> > -#ifdef CONFIG_64BIT
> > -#define THREAD_SIZE_ORDER (2 + KASAN_STACK_ORDER)
> > -#else
> > -#define THREAD_SIZE_ORDER (1 + KASAN_STACK_ORDER)
> > -#endif
> > +#define THREAD_SIZE_ORDER CONFIG_THREAD_SIZE_ORDER
> > #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
>
> This doesn't actually allow additional THREAD_SIZE values, as you
> still round up to the nearest power of two.
>
> I think all the non-arch code can deal with non-power-of-2
> sizes, so you'd just need
>
> #define THREAD_SIZE round_up(CONFIG_THREAD_SIZE, PAGE_SIZE)
>
> and fix up the risc-v specific code to do the right thing
> as well. I now see that THREAD_SIZE_ORDER is not actually
> used anywhere with CONFIG_VMAP_STACK, so I suppose that
> definition can be skipped, but you still need a THREAD_ALIGN
> definition that is a power of two and at least a page larger
> than THREAD_SIZE.
Sorry, I missed this part. I would RESEND v5
>
> Arnd
--
Best Regards
Guo Ren
next prev parent reply other threads:[~2022-09-19 8:35 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 2:24 [PATCH V4 0/9] riscv: Add GENERIC_ENTRY, irq stack support guoren
2022-09-08 2:24 ` [PATCH V4 1/8] riscv: elf_kexec: Fixup compile warning guoren
2022-09-08 2:25 ` [PATCH V4 2/8] riscv: compat_syscall_table: " guoren
2022-09-08 2:25 ` [PATCH V4 3/8] riscv: ptrace: Remove duplicate operation guoren
2022-09-08 2:25 ` [PATCH V4 4/8] riscv: traps: Add noinstr to prevent instrumentation inserted guoren
2022-09-08 7:33 ` Peter Zijlstra
2022-09-10 9:17 ` Guo Ren
2022-09-10 12:46 ` Guo Ren
2022-09-11 15:09 ` Peter Zijlstra
2022-09-11 16:20 ` Guo Ren
2022-09-08 2:25 ` [PATCH V4 5/8] riscv: convert to generic entry guoren
2022-09-15 13:50 ` Yipeng Zou
2022-09-08 2:25 ` [PATCH V4 6/8] riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK guoren
2022-09-08 16:08 ` Sebastian Andrzej Siewior
2022-09-09 7:30 ` David Laight
2022-09-11 1:13 ` Guo Ren
2022-09-08 2:25 ` [PATCH V4 7/8] riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK guoren
2022-09-08 16:01 ` Sebastian Andrzej Siewior
2022-09-18 15:42 ` Guo Ren
2022-09-08 2:25 ` [PATCH V4 8/8] riscv: Add config of thread stack size guoren
2022-09-08 7:35 ` Arnd Bergmann
2022-09-10 12:52 ` Guo Ren
2022-09-10 16:06 ` Arnd Bergmann
2022-09-10 23:35 ` Guo Ren
2022-09-11 18:39 ` Arnd Bergmann
2022-09-12 4:14 ` Guo Ren
2022-09-12 8:23 ` Arnd Bergmann
2022-09-19 8:38 ` Guo Ren
2022-09-19 8:35 ` Guo Ren [this message]
2022-09-20 0:46 ` Guo Ren
2022-09-20 7:15 ` Arnd Bergmann
2022-09-21 6:11 ` Guo Ren
2022-09-20 7:17 ` Arnd Bergmann
2022-09-21 6:13 ` Guo Ren
2022-09-21 8:23 ` Guo Ren
2022-09-21 10:31 ` Guo Ren
2022-09-21 10:46 ` Guo Ren
2022-09-22 5:55 ` Arnd Bergmann
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