Messages in this thread | | | Date | Mon, 30 May 2022 11:35:10 +0200 | Subject | Re: [PATCH v4] mm: Avoid unnecessary page fault retires on shared memory types | From | Christian Borntraeger <> |
| |
Am 29.05.22 um 22:33 schrieb Heiko Carstens: [...] > > Guess the patch below on top of your patch is what we want. > Just for clarification: if gmap is not NULL then the process is a kvm > process. So, depending on the workload, this optimization makes sense. > > diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c > index 4608cc962ecf..e1d40ca341b7 100644 > --- a/arch/s390/mm/fault.c > +++ b/arch/s390/mm/fault.c > @@ -436,12 +436,11 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) > > /* The fault is fully completed (including releasing mmap lock) */ > if (fault & VM_FAULT_COMPLETED) { > - /* > - * Gmap will need the mmap lock again, so retake it. TODO: > - * only conditionally take the lock when CONFIG_PGSTE set. > - */ > - mmap_read_lock(mm); > - goto out_gmap; > + if (gmap) { > + mmap_read_lock(mm); > + goto out_gmap; > + } > + goto out;
Yes, that makes sense. With that
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
| |