linux-kernel - Re: [PATCH] x86/mce: drop cpu_missing since we have more capable mce_missing

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Message-ID: <YYjuiHN1wKt82fjs@zn.tnic>
Date:   Mon, 8 Nov 2021 10:31:52 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Zhaolong Zhang <zhangzl2013@....com>
Cc:     Tony Luck <tony.luck@...el.com>, x86@...nel.org,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: Re: [PATCH] x86/mce: drop cpu_missing since we have more capable
 mce_missing_cpus

On Mon, Nov 08, 2021 at 04:28:32PM +0800, Zhaolong Zhang wrote:
> move mce_missing_cpus checking into mce_panic() as well, because we don't want
> to lose the cpu missing information in case mca_cfg.tolerant > 1 and there is
> no_way_out.
> 
> Signed-off-by: Zhaolong Zhang <zhangzl2013@....com>
> ---
>  arch/x86/kernel/cpu/mce/core.c | 38 ++++++++++++++++++++--------------
>  1 file changed, 22 insertions(+), 16 deletions(-)

I was actually expecting to see something like this:

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 6ed365337a3b..30de00fe0d7a 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -99,7 +99,6 @@ struct mca_config mca_cfg __read_mostly = {
 
 static DEFINE_PER_CPU(struct mce, mces_seen);
 static unsigned long mce_need_notify;
-static int cpu_missing;
 
 /*
  * MCA banks polled by the period polling timer for corrected events.
@@ -314,8 +313,6 @@ static void mce_panic(const char *msg, struct mce *final, char *exp)
 		if (!apei_err)
 			apei_err = apei_write_mce(final);
 	}
-	if (cpu_missing)
-		pr_emerg(HW_ERR "Some CPUs didn't answer in synchronization\n");
 	if (exp)
 		pr_emerg(HW_ERR "Machine check: %s\n", exp);
 	if (!fake_panic) {
@@ -891,7 +888,6 @@ static int mce_timed_out(u64 *t, const char *msg)
 					 cpumask_pr_args(&mce_missing_cpus));
 			mce_panic(msg, NULL, NULL);
 		}
-		cpu_missing = 1;
 		return 1;
 	}
 	*t -= SPINUNIT;
@@ -2702,7 +2698,6 @@ struct dentry *mce_get_debugfs_dir(void)
 
 static void mce_reset(void)
 {
-	cpu_missing = 0;
 	atomic_set(&mce_fake_panicked, 0);
 	atomic_set(&mce_executing, 0);
 	atomic_set(&mce_callin, 0);

-- 
Regards/Gruss,
    Boris.

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