From: Muchun Song <muchun.song@linux.dev>
To: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: tglx@linutronix.de, mingo@redhat.com, luto@kernel.org,
peterz@infradead.org, paulmck@kernel.org, bp@alien8.de,
dave.hansen@linux.intel.com, pbonzini@redhat.com,
bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org,
nadav.amit@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 05/12] smp: Alloc percpu csd data in smpcfd_prepare_cpu() only once
Date: Thu, 23 Apr 2026 15:29:55 +0800 [thread overview]
Message-ID: <5E373C0D-EB29-4F57-9DB7-AD3BBD0CE0F0@linux.dev> (raw)
In-Reply-To: <20260422064022.3791652-6-zhouchuyi@bytedance.com>
> On Apr 22, 2026, at 14:40, Chuyi Zhou <zhouchuyi@bytedance.com> wrote:
>
> Later patch would enable preemption during csd_lock_wait() in
> smp_call_function_many_cond(), which may cause access cfd->csd data that
> has already been freed in smpcfd_dead_cpu().
>
> One way to fix the above issue is to use the RCU mechanism to protect the
> csd data and wait for all read critical sections to exit before freeing
> the memory in smpcfd_dead_cpu(), but this could delay CPU shutdown. This
> patch chooses a simpler approach: allocate the percpu csd on the UP side
> only once and skip freeing the csd memory in smpcfd_dead_cpu().
>
> Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Thanks.
next prev parent reply other threads:[~2026-04-23 7:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-22 6:40 [PATCH v5 00/12] Allow preemption during IPI completion waiting to improve real-time performance Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 01/12] smp: Disable preemption explicitly in __csd_lock_wait Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 02/12] smp: Enable preemption early in smp_call_function_single Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 03/12] smp: Refactor remote CPU selection in smp_call_function_any() Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 04/12] smp: Use task-local IPI cpumask in smp_call_function_many_cond() Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 05/12] smp: Alloc percpu csd data in smpcfd_prepare_cpu() only once Chuyi Zhou
2026-04-23 7:29 ` Muchun Song [this message]
2026-04-22 6:40 ` [PATCH v5 06/12] smp: Enable preemption early in smp_call_function_many_cond Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 07/12] smp: Remove preempt_disable from smp_call_function Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 08/12] smp: Remove preempt_disable from on_each_cpu_cond_mask Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 09/12] scftorture: Remove preempt_disable in scftorture_invoke_one Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 10/12] x86/mm: Move flush_tlb_info back to the stack Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 11/12] x86/mm: Enable preemption during native_flush_tlb_multi Chuyi Zhou
2026-04-22 6:40 ` [PATCH v5 12/12] x86/mm: Enable preemption during flush_tlb_kernel_range Chuyi Zhou
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5E373C0D-EB29-4F57-9DB7-AD3BBD0CE0F0@linux.dev \
--to=muchun.song@linux.dev \
--cc=bigeasy@linutronix.de \
--cc=bp@alien8.de \
--cc=clrkwllms@kernel.org \
--cc=dave.hansen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=nadav.amit@gmail.com \
--cc=paulmck@kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=zhouchuyi@bytedance.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.