The following commit has been merged into the ras/core branch of tip:
Commit-ID: 108c6494bdf1dfeaefc0a506e2f471aa92fafdd6
Gitweb: https://git.kernel.org/tip/108c6494bdf1dfeaefc0a506e2f471aa92fafdd6
Author: Tony Luck <tony.luck@xxxxxxxxx>
AuthorDate: Thu, 07 Mar 2024 11:27:04 -08:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Tue, 26 Mar 2024 12:40:42 +01:00
x86/mce: Dynamically size space for machine check records
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@xxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
Reviewed-by: Avadhut Naik <avadhut.naik@xxxxxxx>
Link: https://lore.kernel.org/r/20240307192704.37213-1-tony.luck@xxxxxxxxx
---
arch/x86/kernel/cpu/mce/genpool.c | 40 ++++++++++++++++++------------
1 file changed, 25 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/genpool.c b/arch/x86/kernel/cpu/mce/genpool.c
index fbe8b61..4284749 100644
--- a/arch/x86/kernel/cpu/mce/genpool.c
+++ b/arch/x86/kernel/cpu/mce/genpool.c
@@ -16,14 +16,14 @@
* 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 +118,32 @@ 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;
-
- 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);
+ void *mce_pool;
+
+ order = order_base_2(sizeof(struct mce_evt_llist));
+ gpool = gen_pool_create(order, -1);
+ if (!gpool)
+ return ret;
+
+ mce_numrecords = max(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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