From: Gavin Shan <gshan@redhat.com>
To: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Cc: kvmarm@lists.cs.columbia.edu, kvmarm@lists.linux.dev,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
ajones@ventanamicro.com, pbonzini@redhat.com, maz@kernel.org,
shuah@kernel.org, oliver.upton@linux.dev, seanjc@google.com,
peterx@redhat.com, ricarkol@google.com, zhenyzha@redhat.com,
shan.gavin@gmail.com
Subject: Re: [PATCH 3/6] KVM: selftests: memslot_perf_test: Probe memory slots for once
Date: Tue, 18 Oct 2022 06:18:39 +0800 [thread overview]
Message-ID: <b720dbad-4b8b-a617-f782-7f95bcdb3d54@redhat.com> (raw)
Message-ID: <20221017221839.VlJIz8p1oz6ZzPVEWalmbZ6hi_o7lvLucQfU7WUUXkU@z> (raw)
In-Reply-To: <fb3926da-a683-2811-71a4-31fe36a9cb50@maciej.szmigiero.name>
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@redhat.com>
>> ---
>> .../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
next prev parent reply other threads:[~2022-10-17 22:19 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-14 7:19 [PATCH 0/6] KVM: selftests: memslot_perf_test: aarch64 cleanup/fixes Gavin Shan
2022-10-14 7:19 ` Gavin Shan
2022-10-14 7:19 ` [PATCH 1/6] KVM: selftests: memslot_perf_test: Use data->nslots in prepare_vm() Gavin Shan
2022-10-14 7:19 ` Gavin Shan
2022-10-14 7:19 ` [PATCH 2/6] KVM: selftests: memslot_perf_test: Consolidate loop conditions " Gavin Shan
2022-10-14 7:19 ` Gavin Shan
2022-10-14 7:19 ` [PATCH 3/6] KVM: selftests: memslot_perf_test: Probe memory slots for once Gavin Shan
2022-10-14 7:19 ` Gavin Shan
2022-10-17 17:34 ` Maciej S. Szmigiero
2022-10-17 17:34 ` Maciej S. Szmigiero
2022-10-17 22:18 ` Gavin Shan [this message]
2022-10-17 22:18 ` Gavin Shan
2022-10-14 7:19 ` [PATCH 4/6] KVM: selftests: memslot_perf_test: Support variable guest page size Gavin Shan
2022-10-14 7:19 ` Gavin Shan
2022-10-17 21:31 ` Maciej S. Szmigiero
2022-10-17 21:31 ` Maciej S. Szmigiero
2022-10-18 0:46 ` Gavin Shan
2022-10-18 0:46 ` Gavin Shan
2022-10-18 0:51 ` Gavin Shan
2022-10-18 0:51 ` Gavin Shan
2022-10-18 15:56 ` Maciej S. Szmigiero
2022-10-18 15:56 ` Maciej S. Szmigiero
2022-10-19 0:26 ` Gavin Shan
2022-10-19 0:26 ` Gavin Shan
2022-10-19 20:18 ` Maciej S. Szmigiero
2022-10-19 20:18 ` Maciej S. Szmigiero
2022-10-20 7:19 ` Gavin Shan
2022-10-20 7:19 ` Gavin Shan
2022-10-14 7:19 ` [PATCH 5/6] KVM: selftests: memslot_perf_test: Consolidate memory sizes Gavin Shan
2022-10-14 7:19 ` Gavin Shan
2022-10-17 21:36 ` Maciej S. Szmigiero
2022-10-17 21:36 ` Maciej S. Szmigiero
2022-10-17 22:08 ` Sean Christopherson
2022-10-17 22:08 ` Sean Christopherson
2022-10-17 22:51 ` Gavin Shan
2022-10-17 22:51 ` Gavin Shan
2022-10-17 22:56 ` Maciej S. Szmigiero
2022-10-17 22:56 ` Maciej S. Szmigiero
2022-10-17 23:10 ` Gavin Shan
2022-10-17 23:10 ` Gavin Shan
2022-10-17 23:32 ` Sean Christopherson
2022-10-17 23:32 ` Sean Christopherson
2022-10-17 23:39 ` Gavin Shan
2022-10-17 23:39 ` Gavin Shan
2022-10-18 7:47 ` Oliver Upton
2022-10-18 7:47 ` Oliver Upton
2022-10-18 8:48 ` Gavin Shan
2022-10-18 8:48 ` Gavin Shan
2022-10-18 1:13 ` Gavin Shan
2022-10-18 1:13 ` Gavin Shan
2022-10-14 7:19 ` [PATCH 6/6] KVM: selftests: memslot_perf_test: Report optimal memory slots Gavin Shan
2022-10-14 7:19 ` Gavin Shan
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