From: Peter Zijlstra <peterz@infradead.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: rafael@kernel.org, ak@linux.intel.com, bp@alien8.de,
dan.j.williams@intel.com, dave.hansen@linux.intel.com,
hpa@zytor.com, knsathya@kernel.org, linux-acpi@vger.kernel.org,
linux-kernel@vger.kernel.org, mingo@redhat.com,
rjw@rjwysocki.net, sathyanarayanan.kuppuswamy@linux.intel.com,
tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org
Subject: Re: [PATCH 3/4] ACPI: processor idle: Only flush cache on entering C3
Date: Mon, 6 Dec 2021 16:03:42 +0100 [thread overview]
Message-ID: <Ya4mTij+eQPq8dnu@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20211206122952.74139-4-kirill.shutemov@linux.intel.com>
On Mon, Dec 06, 2021 at 03:29:51PM +0300, Kirill A. Shutemov wrote:
> According to the ACPI spec v6.4, section 8.2, cache flushing required
> on entering C3 power state.
>
> Avoid flushing cache on entering other power states.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> drivers/acpi/processor_idle.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 76ef1bcc8848..01495aca850e 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -567,7 +567,8 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
> {
> struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
>
> - ACPI_FLUSH_CPU_CACHE();
> + if (cx->type == ACPI_STATE_C3)
> + ACPI_FLUSH_CPU_CACHE();
>
acpi_idle_enter() already does this, acpi_idle_enter_s2idle() has it
confused again,
Also, I think acpi_idle_enter() does it too late; consider
acpi_idle_enter_mb(). Either that or the BM crud needs more comments.
next prev parent reply other threads:[~2021-12-06 15:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <YZPbQVwWOJCrAH78@zn.tnic>
2021-11-19 4:03 ` [PATCH v2] x86: Skip WBINVD instruction for VM guest Kuppuswamy Sathyanarayanan
2021-11-25 0:40 ` Thomas Gleixner
2021-12-02 22:21 ` Kirill A. Shutemov
2021-12-02 22:38 ` Dave Hansen
2021-12-02 23:48 ` Thomas Gleixner
2021-12-03 23:49 ` Kirill A. Shutemov
2021-12-04 0:20 ` Dave Hansen
2021-12-04 0:54 ` Kirill A. Shutemov
2021-12-06 15:35 ` Dave Hansen
2021-12-06 16:39 ` Dan Williams
2021-12-06 16:53 ` Dave Hansen
2021-12-06 17:51 ` Dan Williams
2021-12-04 20:27 ` Rafael J. Wysocki
2021-12-06 12:29 ` [PATCH 0/4] ACPI/ACPICA: Only flush caches on S1/S2/S3 and C3 Kirill A. Shutemov
2021-12-06 12:29 ` [PATCH 1/4] ACPICA: Do not flush cache for on entering S4 and S5 Kirill A. Shutemov
2021-12-08 14:58 ` Rafael J. Wysocki
2021-12-06 12:29 ` [PATCH 2/4] ACPI: PM: Remove redundant cache flushing Kirill A. Shutemov
2021-12-07 16:35 ` Rafael J. Wysocki
2021-12-09 13:32 ` Kirill A. Shutemov
2021-12-17 18:04 ` Rafael J. Wysocki
2021-12-06 12:29 ` [PATCH 3/4] ACPI: processor idle: Only flush cache on entering C3 Kirill A. Shutemov
2021-12-06 15:03 ` Peter Zijlstra [this message]
2021-12-08 16:26 ` Rafael J. Wysocki
2021-12-09 13:33 ` Kirill A. Shutemov
2021-12-17 17:58 ` Rafael J. Wysocki
2021-12-06 12:29 ` [PATCH 4/4] ACPI: PM: Avoid cache flush on entering S4 Kirill A. Shutemov
2021-12-08 15:10 ` Rafael J. Wysocki
2021-12-08 16:04 ` Kirill A. Shutemov
2021-12-08 16:16 ` Rafael J. Wysocki
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=Ya4mTij+eQPq8dnu@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=ak@linux.intel.com \
--cc=bp@alien8.de \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=knsathya@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=rafael@kernel.org \
--cc=rjw@rjwysocki.net \
--cc=sathyanarayanan.kuppuswamy@linux.intel.com \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).