On 10/18/22 1:34 AM, Maciej S. Szmigiero wrote:
On 14.10.2022 09:19, Gavin Shan wrote:prepare_vm() is called in every iteration and run. The allowed memory slots (KVM_CAP_NR_MEMSLOTS) are probed for multiple times. It's not free and unnecessary. Move the probing logic for the allowed memory slots to parse_args() for once, which is upper layer of prepare_vm(). No functional change intended. Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx> --- .../testing/selftests/kvm/memslot_perf_test.c | 29 ++++++++++--------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testing/selftests/kvm/memslot_perf_test.c index dcb492b3f27b..d5aa9148f96f 100644 --- a/tools/testing/selftests/kvm/memslot_perf_test.c +++ b/tools/testing/selftests/kvm/memslot_perf_test.c @@ -245,27 +245,17 @@ static bool prepare_vm(struct vm_data *data, int nslots, uint64_t *maxslots, void *guest_code, uint64_t mempages, struct timespec *slot_runtime) { - uint32_t max_mem_slots; uint64_t rempages; uint64_t guest_addr; uint32_t slot; struct timespec tstart; struct sync_area *sync; - max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS); - TEST_ASSERT(max_mem_slots > 1, - "KVM_CAP_NR_MEMSLOTS should be greater than 1"); - TEST_ASSERT(nslots > 1 || nslots == -1, - "Slot count cap should be greater than 1"); - if (nslots != -1) - max_mem_slots = min(max_mem_slots, (uint32_t)nslots); - pr_info_v("Allowed number of memory slots: %"PRIu32"\n", max_mem_slots); - TEST_ASSERT(mempages > 1, "Can't test without any memory"); data->npages = mempages; - data->nslots = max_mem_slots - 1; + data->nslots = nslots; data->pages_per_slot = mempages / data->nslots; if (!data->pages_per_slot) { *maxslots = mempages + 1; @@ -885,8 +875,8 @@ static bool parse_args(int argc, char *argv[], break; case 's': targs->nslots = atoi(optarg); - if (targs->nslots <= 0 && targs->nslots != -1) { - pr_info("Slot count cap has to be positive or -1 for no cap\n"); + if (targs->nslots <= 1 && targs->nslots != -1) { + pr_info("Slot count cap must be larger than 1 or -1 for no cap\n"); return false; } break; @@ -932,6 +922,19 @@ static bool parse_args(int argc, char *argv[], return false; } + /* Memory slot 0 is reserved */ + if (targs->nslots == -1) { + targs->nslots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS) - 1; + if (targs->nslots < 1) { + pr_info("KVM_CAP_NR_MEMSLOTS should be greater than 1\n"); + return false; + } + } else { + targs->nslots--; + } + + pr_info_v("Number of memory slots: %d\n", targs->nslots); +Can't see any capping of the command line provided slot count to KVM_CAP_NR_MEMSLOTS value, like the old code did.
Indeed. I wanted to avoid extra variable @max_mem_slots and the capping is missed. I will fix it up in next revision.
return true; }
Thanks, Gavin
