[tip: ras/core] RAS/CEC: Reduce offline page threshold for Intel systems

[tip-bot2 for Tony Luck]

The following commit has been merged into the ras/core branch of tip:

Commit-ID:     d25c6948a6aad787d9fd64de6b5362c3f23cc8d0
Gitweb:        https://git.kernel.org/tip/d25c6948a6aad787d9fd64de6b5362c3f23cc8d0
Author:        Tony Luck <tony.luck@xxxxxxxxx>
AuthorDate:    Tue, 02 Aug 2022 09:18:47 -07:00
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Mon, 22 Aug 2022 19:30:02 +02:00

RAS/CEC: Reduce offline page threshold for Intel systems

A large scale study of memory errors on Intel systems in data centers
showed that aggressively taking pages with corrected errors offline is
the best strategy of using corrected errors as a predictor of future
uncorrected errors.

Set the threshold to "2" on Intel systems. AMD guidance is that this is
not necessary for their systems.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Link: https://lore.kernel.org/r/20220607212015.175591-1-tony.luck@xxxxxxxxx
Link: https://lore.kernel.org/r/YulOZ/Eso0bwUcC4@xxxxxxxxxxxxxxxxxxxxxxxxx
---
 drivers/ras/cec.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 42f2fc0..321af49 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -556,6 +556,14 @@ static int __init cec_init(void)
 	if (ce_arr.disabled)
 		return -ENODEV;
 
+	/*
+	 * Intel systems may avoid uncorrectable errors
+	 * if pages with corrected errors are aggressively
+	 * taken offline.
+	 */
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+		action_threshold = 2;
+
 	ce_arr.array = (void *)get_zeroed_page(GFP_KERNEL);
 	if (!ce_arr.array) {
 		pr_err("Error allocating CE array page!\n");