For systems which do not have CONFIG_PREEMPT set and
if there is a heavy multi-threaded load/store operation happening
on pmem + sometimes along with device latencies, softlockup warnings like
this could trigger. This was seen on Power where pagesize is 64K.
To avoid softlockup, this patch adds a cond_resched() in this path.
<...>
watchdog: BUG: soft lockup - CPU#31 stuck for 22s!
<...>
CPU: 31 PID: 15627 <..> 5.3.18-20
<...>
NIP memcpy_power7+0x43c/0x7e0
LR memcpy_flushcache+0x28/0xa0
Call Trace:
memcpy_power7+0x274/0x7e0 (unreliable)
memcpy_flushcache+0x28/0xa0
write_pmem+0xa0/0x100 [nd_pmem]
pmem_do_bvec+0x1f0/0x420 [nd_pmem]
pmem_make_request+0x14c/0x370 [nd_pmem]
generic_make_request+0x164/0x400
submit_bio+0x134/0x2e0
submit_bio_wait+0x70/0xc0
blkdev_issue_zeroout+0xf4/0x2a0
xfs_zero_extent+0x90/0xc0 [xfs]
xfs_bmapi_convert_unwritten+0x198/0x230 [xfs]
xfs_bmapi_write+0x284/0x630 [xfs]
xfs_iomap_write_direct+0x1f0/0x3e0 [xfs]
xfs_file_iomap_begin+0x344/0x690 [xfs]
dax_iomap_pmd_fault+0x488/0xc10
__xfs_filemap_fault+0x26c/0x2b0 [xfs]
__handle_mm_fault+0x794/0x1af0
handle_mm_fault+0x12c/0x220
__do_page_fault+0x290/0xe40
do_page_fault+0x38/0xc0
handle_page_fault+0x10/0x30
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
Signed-off-by: Ritesh Harjani <rite...@linux.ibm.com>
---
drivers/nvdimm/pmem.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 2df6994acf83..fcf7af13897e 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -214,6 +214,7 @@ static blk_qc_t pmem_make_request(struct request_queue *q,
struct bio *bio)
bio->bi_status = rc;
break;
}
+ cond_resched();
}
if (do_acct)
nd_iostat_end(bio, start);
--
2.25.4
