Commit 108c6494 authored by Tony Luck's avatar Tony Luck Committed by Borislav Petkov (AMD)

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: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarSohil Mehta <sohil.mehta@intel.com>
Reviewed-by: default avatarAvadhut Naik <avadhut.naik@amd.com>
Link: https://lore.kernel.org/r/20240307192704.37213-1-tony.luck@intel.com
parent 4cece764
......@@ -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;
}
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment