Attachment 875555 Details for Bug 1222241

[patch] Patch for SLE15-SP5

x86-mce-Dynamically-size-space-for-machine-check-rec.patch (text/plain), 3.21 KB, created by Takashi Iwai on 2024-06-18 14:24:44 UTC

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Creator: Takashi Iwai

Created: 2024-06-18 14:24:44 UTC

Size: 3.21 KB

patch

obsolete

>From 108c6494bdf1dfeaefc0a506e2f471aa92fafdd6 Mon Sep 17 00:00:00 2001
>From: Tony Luck <tony.luck@intel.com>
>Date: Thu, 7 Mar 2024 11:27:04 -0800
>Subject: [PATCH] x86/mce: Dynamically size space for machine check records
>Git-commit: 108c6494bdf1dfeaefc0a506e2f471aa92fafdd6
>Patch-mainline: v6.10-rc1
>References: bsc#1222241
>
>[ backport note: add the missing slab.h inclusion and adjust max()
>  with max_t(int) for fixing build errors -- tiwai ]
>
>Systems with a large number of CPUs may generate a large number of
>machine check records when things go seriously wrong. But Linux has
>a fixed-size buffer that can only capture a few dozen errors.
>
>Allocate space based on the number of CPUs (with a minimum value based
>on the historical fixed buffer that could store 80 records).
>
>  [ bp: Rename local var from tmpp to something more telling: gpool. ]
>
>Signed-off-by: Tony Luck <tony.luck@intel.com>
>Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
>Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
>Reviewed-by: Avadhut Naik <avadhut.naik@amd.com>
>Link: https://lore.kernel.org/r/20240307192704.37213-1-tony.luck@intel.com
>Acked-by: Takashi Iwai <tiwai@suse.de>
>
>---
> arch/x86/kernel/cpu/mce/genpool.c |   39 ++++++++++++++++++++++++--------------
> 1 file changed, 25 insertions(+), 14 deletions(-)
>
>--- a/arch/x86/kernel/cpu/mce/genpool.c
>+++ b/arch/x86/kernel/cpu/mce/genpool.c
>@@ -9,6 +9,7 @@
> #include <linux/mm.h>
> #include <linux/genalloc.h>
> #include <linux/llist.h>
>+#include <linux/slab.h>
> #include "internal.h"
> 
> /*
>@@ -16,14 +17,14 @@
>  * used to save error information organized in a lock-less list.
>  *
>  * This memory pool is only to be used to save MCE records in MCE context.
>- * MCE events are rare, so a fixed size memory pool should be enough. Use
>- * 2 pages to save MCE events for now (~80 MCE records at most).
>+ * MCE events are rare, so a fixed size memory pool should be enough.
>+ * Allocate on a sliding scale based on number of CPUs.
>  */
>-#define MCE_POOLSZ	(2 * PAGE_SIZE)
>+#define MCE_MIN_ENTRIES	80
>+#define MCE_PER_CPU	2
> 
> static struct gen_pool *mce_evt_pool;
> static LLIST_HEAD(mce_event_llist);
>-static char gen_pool_buf[MCE_POOLSZ];
> 
> /*
>  * Compare the record "t" with each of the records on list "l" to see if
>@@ -118,22 +119,32 @@ int mce_gen_pool_add(struct mce *mce)
> 
> static int mce_gen_pool_create(void)
> {
>-	struct gen_pool *tmpp;
>+	int mce_numrecords, mce_poolsz, order;
>+	struct gen_pool *gpool;
> 	int ret = -ENOMEM;
>+	void *mce_pool;
> 
>-	tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
>-	if (!tmpp)
>-		goto out;
>-
>-	ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
>+	order = order_base_2(sizeof(struct mce_evt_llist));
>+	gpool = gen_pool_create(order, -1);
>+	if (!gpool)
>+		return ret;
>+
>+	mce_numrecords = max_t(int, MCE_MIN_ENTRIES, num_possible_cpus() * MCE_PER_CPU);
>+	mce_poolsz = mce_numrecords * (1 << order);
>+	mce_pool = kmalloc(mce_poolsz, GFP_KERNEL);
>+	if (!mce_pool) {
>+		gen_pool_destroy(gpool);
>+		return ret;
>+	}
>+	ret = gen_pool_add(gpool, (unsigned long)mce_pool, mce_poolsz, -1);
> 	if (ret) {
>-		gen_pool_destroy(tmpp);
>-		goto out;
>+		gen_pool_destroy(gpool);
>+		kfree(mce_pool);
>+		return ret;
> 	}
> 
>-	mce_evt_pool = tmpp;
>+	mce_evt_pool = gpool;
> 
>-out:
> 	return ret;
> }
>

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Attachments on bug 1222241: 875555