From: Tony Luck <tony.luck@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "Naik, Avadhut" <avadnaik@amd.com>,
"Mehta, Sohil" <sohil.mehta@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"yazen.ghannam@amd.com" <yazen.ghannam@amd.com>,
Avadhut Naik <avadhut.naik@amd.com>
Subject: [PATCH] x86/mce: Dynamically size space for machine check records
Date: Wed, 28 Feb 2024 15:14:04 -0800 [thread overview]
Message-ID: <Zd--PJp-NbXGrb39@agluck-desk3> (raw)
In-Reply-To: <20240212224220.GSZcqezMhPojxvIcvO@fat_crate.local>
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 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).
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
Discussion earlier concluded with the realization that it is
safe to dynamically allocate the mce_evt_pool at boot time.
So here's a patch to do that. Scaling algorithm here is a
simple linear "4 records per possible CPU" with a minimum
of 80 to match the legacy behavior. I'm open to other
suggestions.
Note that I threw in a "+1" to the return from ilog2() when
calling gen_pool_create(). From reading code, and running
some tests, it appears that the min_alloc_order argument
needs to be large enough to allocate one of the mce_evt_llist
structures.
Some other gen_pool users in Linux may also need this "+1".
arch/x86/kernel/cpu/mce/genpool.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/genpool.c b/arch/x86/kernel/cpu/mce/genpool.c
index fbe8b61c3413..a1f0a8f29cf5 100644
--- a/arch/x86/kernel/cpu/mce/genpool.c
+++ b/arch/x86/kernel/cpu/mce/genpool.c
@@ -16,14 +16,13 @@
* 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
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
@@ -118,14 +117,25 @@ int mce_gen_pool_add(struct mce *mce)
static int mce_gen_pool_create(void)
{
+ int mce_numrecords, mce_poolsz;
struct gen_pool *tmpp;
int ret = -ENOMEM;
+ void *mce_pool;
+ int order;
- tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
+ order = ilog2(sizeof(struct mce_evt_llist)) + 1;
+ tmpp = gen_pool_create(order, -1);
if (!tmpp)
goto out;
- ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
+ mce_numrecords = max(80, num_possible_cpus() * 4);
+ mce_poolsz = mce_numrecords * (1 << order);
+ mce_pool = kmalloc(mce_poolsz, GFP_KERNEL);
+ if (!mce_pool) {
+ gen_pool_destroy(tmpp);
+ goto out;
+ }
+ ret = gen_pool_add(tmpp, (unsigned long)mce_pool, mce_poolsz, -1);
if (ret) {
gen_pool_destroy(tmpp);
goto out;
--
2.43.0
next prev parent reply other threads:[~2024-02-28 23:14 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 22:56 [PATCH 0/2] Extend size of the MCE Records pool Avadhut Naik
2024-02-07 22:56 ` [PATCH 1/2] x86/MCE: " Avadhut Naik
2024-02-08 0:02 ` Luck, Tony
2024-02-08 17:41 ` Naik, Avadhut
2024-02-08 17:47 ` Naik, Avadhut
2024-02-08 18:39 ` Luck, Tony
2024-02-09 19:47 ` Naik, Avadhut
2024-02-08 21:09 ` Sohil Mehta
2024-02-09 19:52 ` Naik, Avadhut
2024-02-07 22:56 ` [PATCH 2/2] x86/MCE: Add command line option to extend " Avadhut Naik
2024-02-09 1:36 ` Sohil Mehta
2024-02-09 20:02 ` Naik, Avadhut
2024-02-09 20:09 ` Borislav Petkov
2024-02-09 20:35 ` Naik, Avadhut
2024-02-09 20:51 ` Borislav Petkov
2024-02-10 7:52 ` Borislav Petkov
2024-02-10 21:15 ` Naik, Avadhut
2024-02-11 11:14 ` Borislav Petkov
2024-02-12 2:54 ` Naik, Avadhut
2024-02-12 8:58 ` Borislav Petkov
2024-02-12 9:32 ` Borislav Petkov
2024-02-12 17:29 ` Luck, Tony
2024-02-12 17:54 ` Borislav Petkov
2024-02-12 18:45 ` Luck, Tony
2024-02-12 19:14 ` Borislav Petkov
2024-02-12 19:41 ` Luck, Tony
2024-02-12 21:37 ` Tony Luck
2024-02-12 22:08 ` Borislav Petkov
2024-02-12 22:19 ` Borislav Petkov
2024-02-12 22:42 ` Borislav Petkov
2024-02-28 23:14 ` Tony Luck [this message]
2024-02-29 0:39 ` [PATCH] x86/mce: Dynamically size space for machine check records Sohil Mehta
2024-02-29 0:44 ` Luck, Tony
2024-02-29 1:56 ` Sohil Mehta
2024-02-29 15:49 ` Yazen Ghannam
2024-02-29 17:22 ` Tony Luck
2024-02-29 17:21 ` Tony Luck
2024-02-29 23:56 ` Sohil Mehta
2024-02-29 6:42 ` Naik, Avadhut
2024-02-29 8:39 ` Borislav Petkov
2024-02-29 17:47 ` Tony Luck
2024-02-29 18:28 ` Naik, Avadhut
2024-02-29 18:38 ` Luck, Tony
2024-02-29 17:26 ` Tony Luck
2024-03-06 21:52 ` Naik, Avadhut
2024-03-06 22:07 ` Luck, Tony
2024-03-06 23:21 ` Naik, Avadhut
2024-02-15 20:18 ` [PATCH 2/2] x86/MCE: Add command line option to extend MCE Records pool Naik, Avadhut
2024-02-15 20:15 ` Naik, Avadhut
2024-02-15 20:14 ` Naik, Avadhut
2024-02-12 18:47 ` Yazen Ghannam
2024-02-12 18:58 ` Luck, Tony
2024-02-12 19:40 ` Naik, Avadhut
2024-02-12 20:18 ` Borislav Petkov
2024-02-12 20:51 ` Naik, Avadhut
2024-02-12 19:43 ` Yazen Ghannam
2024-02-12 19:49 ` Luck, Tony
2024-02-12 20:10 ` Borislav Petkov
2024-02-12 20:44 ` Paul E. McKenney
2024-02-12 21:18 ` Luck, Tony
2024-02-12 21:27 ` Borislav Petkov
2024-02-12 22:46 ` Paul E. McKenney
2024-02-12 22:53 ` Luck, Tony
2024-02-12 23:10 ` Borislav Petkov
2024-02-13 1:07 ` Paul E. McKenney
2024-02-09 20:16 ` Sohil Mehta
2024-02-09 20:28 ` Luck, Tony
2024-02-09 21:02 ` Sohil Mehta
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