From: Oleg Nesterov <oleg@redhat.com>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave@sr71.net>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Uros Bizjak <ubizjak@gmail.com>,
Nathan Chancellor <nathan@kernel.org>
Subject: Re: [PATCH 3/9] x86/fpu: Make task_struct::thread constant size
Date: Tue, 11 Jun 2024 14:42:13 +0200 [thread overview]
Message-ID: <20240611124145.GA26798@redhat.com> (raw)
In-Reply-To: <20240610211350.GA1613053@thelio-3990X>
I don't think this can explain the problem reported by Nathan, but.
On 06/08, Ingo Molnar wrote:
>
> +static struct fpu x86_init_fpu __read_mostly;
> +
> static void __init fpu__init_system_early_generic(void)
> {
> + int this_cpu = smp_processor_id();
> +
> + fpstate_reset(&x86_init_fpu);
> + current->thread.fpu = &x86_init_fpu;
OK,
> + per_cpu(fpu_fpregs_owner_ctx, this_cpu) = &x86_init_fpu;
> + x86_init_fpu.last_cpu = this_cpu;
Why? I think it should do
x86_init_fpu.last_cpu = -1;
set_thread_flag(TIF_NEED_FPU_LOAD);
And the next patch should kill x86_init_fpu altogether, but keep
TIF_NEED_FPU_LOAD. It should be never cleared if PF_KTHREAD.
Oleg.
next prev parent reply other threads:[~2024-06-11 12:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-08 7:31 [PATCH 00/10, -v4] x86/fpu: Remove thread::fpu Ingo Molnar
2024-06-08 7:31 ` [PATCH 1/9] x86/fpu: Introduce the x86_task_fpu() helper method Ingo Molnar
2024-06-08 7:31 ` [PATCH 2/9] x86/fpu: Convert task_struct::thread.fpu accesses to use x86_task_fpu() Ingo Molnar
2024-06-08 7:31 ` [PATCH 3/9] x86/fpu: Make task_struct::thread constant size Ingo Molnar
2024-06-10 21:13 ` Nathan Chancellor
2024-06-11 12:42 ` Oleg Nesterov [this message]
2024-06-12 8:17 ` Ingo Molnar
2024-06-12 9:40 ` Oleg Nesterov
2024-06-12 18:41 ` Oleg Nesterov
2024-06-12 20:30 ` Oleg Nesterov
2024-06-13 9:36 ` [PATCH 10/9] x86/fpu: Fix 'struct fpu' misalignment on 32-bit kernels Ingo Molnar
2024-06-14 15:16 ` Oleg Nesterov
2024-06-15 10:23 ` Oleg Nesterov
2024-06-16 10:55 ` Oleg Nesterov
2024-06-08 7:31 ` [PATCH 4/9] x86/fpu: Remove the thread::fpu pointer Ingo Molnar
2024-06-08 7:31 ` [PATCH 5/9] x86/fpu: Push 'fpu' pointer calculation into the fpu__drop() call Ingo Molnar
2024-06-08 7:31 ` [PATCH 6/9] x86/fpu: Make sure x86_task_fpu() doesn't get called for PF_KTHREAD tasks during exit Ingo Molnar
2024-06-10 10:01 ` Oleg Nesterov
2024-06-08 7:31 ` [PATCH 7/9] x86/fpu: Remove init_task FPU state dependencies, add debugging warning for PF_KTHREAD tasks Ingo Molnar
2024-06-08 7:31 ` [PATCH 8/9] x86/fpu: Use 'fpstate' variable names consistently Ingo Molnar
2024-06-08 7:31 ` [PATCH 9/9] x86/fpu: Fix stale comment in ex_handler_fprestore() Ingo Molnar
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