diff options
| author | Vaibhav Jain <vaibhav@linux.ibm.com> | 2021-04-04 22:01:48 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-04-14 23:04:12 +1000 |
| commit | a5d6a3e73acbd619dd5b7b831762b755f9e2db80 (patch) | |
| tree | 1b3090fead62137c02ab4d0ddf2d870cfea8cb65 /arch/powerpc/mm/book3s64 | |
| parent | 75b7c05ebf902632f7f540c3eb0a8945c2d74aab (diff) | |
powerpc/mm: Add cond_resched() while removing hpte mappings
While removing large number of mappings from hash page tables for
large memory systems as soft-lockup is reported because of the time
spent inside htap_remove_mapping() like one below:
watchdog: BUG: soft lockup - CPU#8 stuck for 23s!
<snip>
NIP plpar_hcall+0x38/0x58
LR pSeries_lpar_hpte_invalidate+0x68/0xb0
Call Trace:
0x1fffffffffff000 (unreliable)
pSeries_lpar_hpte_removebolted+0x9c/0x230
hash__remove_section_mapping+0xec/0x1c0
remove_section_mapping+0x28/0x3c
arch_remove_memory+0xfc/0x150
devm_memremap_pages_release+0x180/0x2f0
devm_action_release+0x30/0x50
release_nodes+0x28c/0x300
device_release_driver_internal+0x16c/0x280
unbind_store+0x124/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
__vfs_write+0x3c/0x70
vfs_write+0xd4/0x270
ksys_write+0xdc/0x130
system_call+0x5c/0x70
Fix this by adding a cond_resched() to the loop in
htap_remove_mapping() that issues hcall to remove hpte mapping. The
call to cond_resched() is issued every HZ jiffies which should prevent
the soft-lockup from being reported.
Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210404163148.321346-1-vaibhav@linux.ibm.com
Diffstat (limited to 'arch/powerpc/mm/book3s64')
| -rw-r--r-- | arch/powerpc/mm/book3s64/hash_utils.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 7719995323c3..12de1906e97b 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -338,7 +338,7 @@ repeat: int htab_remove_mapping(unsigned long vstart, unsigned long vend, int psize, int ssize) { - unsigned long vaddr; + unsigned long vaddr, time_limit; unsigned int step, shift; int rc; int ret = 0; @@ -351,8 +351,19 @@ int htab_remove_mapping(unsigned long vstart, unsigned long vend, /* Unmap the full range specificied */ vaddr = ALIGN_DOWN(vstart, step); + time_limit = jiffies + HZ; + for (;vaddr < vend; vaddr += step) { rc = mmu_hash_ops.hpte_removebolted(vaddr, psize, ssize); + + /* + * For large number of mappings introduce a cond_resched() + * to prevent softlockup warnings. + */ + if (time_after(jiffies, time_limit)) { + cond_resched(); + time_limit = jiffies + HZ; + } if (rc == -ENOENT) { ret = -ENOENT; continue; |