This patch series improves guest vCPUs performances on Arm during clearing
dirty log operations by taking MMU read lock instead of MMU write lock.
vCPUs write protection faults are fixed in Arm using MMU read locks.
However, when userspace is clearing dirty logs via KVM_CLEAR_DIRTY_LOG
ioctl, then kernel code takes MMU write lock. This will block vCPUs
write protection faults and degrade guest performance. This
degradation gets worse as guest VM size increases in terms of memory and
vCPU count.
In this series, MMU read lock adoption is made possible by using
KVM_PGTABLE_WALK_SHARED flag in page walker.
Patches 1 to 5:
These patches are modifying dirty_log_perf_test. Intent is to mimic
production scenarios where guest keeps on executing while userspace
threads collect and clear dirty logs independently.
Three new command line options are added:
1. j: Allows to run guest vCPUs and main thread collecting dirty logs
independently of each other after initialization is complete.
2. k: Allows to clear dirty logs in smaller chunks compared to existing
whole memslot clear in one call.
3. l: Allows to add customizable wait time between consecutive clear
dirty log calls to mimic sending dirty memory to destination.
Patch 7-8:
These patches refactor code to move MMU lock operations to arch specific
code, refactor Arm's page table walker APIs, and change MMU write lock
for clearing dirty logs to read lock. Patch 8 has results showing
improvements based on dirty_log_perf_test.
Vipin Sharma (9):
KVM: selftests: Allow dirty_log_perf_test to clear dirty memory in
chunks
KVM: selftests: Add optional delay between consecutive Clear-Dirty-Log
calls
KVM: selftests: Pass count of read and write accesses from guest to
host
KVM: selftests: Print read and write accesses of pages by vCPUs in
dirty_log_perf_test
KVM: selftests: Allow independent execution of vCPUs in
dirty_log_perf_test
KVM: arm64: Correct the kvm_pgtable_stage2_flush() documentation
KVM: mmu: Move mmu lock/unlock to arch code for clear dirty log
KMV: arm64: Allow stage2_apply_range_sched() to pass page table walker
flags
KVM: arm64: Run clear-dirty-log under MMU read lock
arch/arm64/include/asm/kvm_pgtable.h | 17 ++-
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 4 +-
arch/arm64/kvm/hyp/pgtable.c | 16 ++-
arch/arm64/kvm/mmu.c | 36 ++++--
arch/mips/kvm/mmu.c | 2 +
arch/riscv/kvm/mmu.c | 2 +
arch/x86/kvm/mmu/mmu.c | 3 +
.../selftests/kvm/dirty_log_perf_test.c | 108 ++++++++++++++----
.../testing/selftests/kvm/include/memstress.h | 13 ++-
tools/testing/selftests/kvm/lib/memstress.c | 43 +++++--
virt/kvm/dirty_ring.c | 2 -
virt/kvm/kvm_main.c | 4 -
12 files changed, 185 insertions(+), 65 deletions(-)
base-commit: 95b9779c1758f03cf494e8550d6249a40089ed1c
--
2.40.0.634.g4ca3ef3211-goog
In dirty_log_perf_test, provide option 'k' to specify the size of the
chunks and clear dirty memory in chunks in each iteration. If this
option is not provided then fallback to old way of clearing whole
memslot in one call per iteration.
In production environment whole memslot is rarely cleared in a single
call, instead clearing operation is split across multiple calls to
reduce time between clearing and sending memory to a remote host. This
change mimics the production usecases and allow to get metrics based on
that.
Signed-off-by: Vipin Sharma <[email protected]>
---
.../selftests/kvm/dirty_log_perf_test.c | 19 ++++++++++++---
.../testing/selftests/kvm/include/memstress.h | 12 ++++++++--
tools/testing/selftests/kvm/lib/memstress.c | 24 ++++++++++++++-----
3 files changed, 44 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
index 416719e20518..0852a7ba42e1 100644
--- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
@@ -134,6 +134,7 @@ struct test_params {
uint32_t write_percent;
uint32_t random_seed;
bool random_access;
+ uint64_t clear_chunk_size;
};
static void run_test(enum vm_guest_mode mode, void *arg)
@@ -144,6 +145,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
uint64_t guest_num_pages;
uint64_t host_num_pages;
uint64_t pages_per_slot;
+ uint64_t pages_per_clear;
struct timespec start;
struct timespec ts_diff;
struct timespec get_dirty_log_total = (struct timespec){0};
@@ -164,6 +166,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
host_num_pages = vm_num_host_pages(mode, guest_num_pages);
pages_per_slot = host_num_pages / p->slots;
+ pages_per_clear = p->clear_chunk_size / getpagesize();
bitmaps = memstress_alloc_bitmaps(p->slots, pages_per_slot);
@@ -244,8 +247,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
if (dirty_log_manual_caps) {
clock_gettime(CLOCK_MONOTONIC, &start);
- memstress_clear_dirty_log(vm, bitmaps, p->slots,
- pages_per_slot);
+ memstress_clear_dirty_log_in_chunks(vm, bitmaps, p->slots,
+ pages_per_slot,
+ pages_per_clear);
ts_diff = timespec_elapsed(start);
clear_dirty_log_total = timespec_add(clear_dirty_log_total,
ts_diff);
@@ -343,6 +347,11 @@ static void help(char *name)
" To leave the application task unpinned, drop the final entry:\n\n"
" ./dirty_log_perf_test -v 3 -c 22,23,24\n\n"
" (default: no pinning)\n");
+ printf(" -k: Specify the chunk size in which dirty memory gets cleared\n"
+ " in memslots in each iteration. If the size is bigger than\n"
+ " the memslot size then whole memslot is cleared in one call.\n"
+ " Size must be aligned to the host page size. e.g. 10M or 3G\n"
+ " (default: UINT64_MAX, clears whole memslot in one call)\n");
puts("");
exit(0);
}
@@ -358,6 +367,7 @@ int main(int argc, char *argv[])
.slots = 1,
.random_seed = 1,
.write_percent = 100,
+ .clear_chunk_size = UINT64_MAX,
};
int opt;
@@ -368,7 +378,7 @@ int main(int argc, char *argv[])
guest_modes_append_default();
- while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:v:x:w:")) != -1) {
+ while ((opt = getopt(argc, argv, "ab:c:eghi:k:m:nop:r:s:v:x:w:")) != -1) {
switch (opt) {
case 'a':
p.random_access = true;
@@ -392,6 +402,9 @@ int main(int argc, char *argv[])
case 'i':
p.iterations = atoi_positive("Number of iterations", optarg);
break;
+ case 'k':
+ p.clear_chunk_size = parse_size(optarg);
+ break;
case 'm':
guest_modes_cmdline(optarg);
break;
diff --git a/tools/testing/selftests/kvm/include/memstress.h b/tools/testing/selftests/kvm/include/memstress.h
index ce4e603050ea..2acc93f76fc3 100644
--- a/tools/testing/selftests/kvm/include/memstress.h
+++ b/tools/testing/selftests/kvm/include/memstress.h
@@ -75,8 +75,16 @@ void memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu *vc
void memstress_enable_dirty_logging(struct kvm_vm *vm, int slots);
void memstress_disable_dirty_logging(struct kvm_vm *vm, int slots);
void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots);
-void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
- int slots, uint64_t pages_per_slot);
+void memstress_clear_dirty_log_in_chunks(struct kvm_vm *vm,
+ unsigned long *bitmaps[], int slots,
+ uint64_t pages_per_slot,
+ uint64_t pages_per_clear);
+static inline void memstress_clear_dirty_log(struct kvm_vm *vm,
+ unsigned long *bitmaps[], int slots,
+ uint64_t pages_per_slot) {
+ memstress_clear_dirty_log_in_chunks(vm, bitmaps, slots, pages_per_slot,
+ pages_per_slot);
+}
unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot);
void memstress_free_bitmaps(unsigned long *bitmaps[], int slots);
diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/selftests/kvm/lib/memstress.c
index 3632956c6bcf..e0c701ab4e9a 100644
--- a/tools/testing/selftests/kvm/lib/memstress.c
+++ b/tools/testing/selftests/kvm/lib/memstress.c
@@ -355,16 +355,28 @@ void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int sl
}
}
-void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
- int slots, uint64_t pages_per_slot)
+void memstress_clear_dirty_log_in_chunks(struct kvm_vm *vm,
+ unsigned long *bitmaps[], int slots,
+ uint64_t pages_per_slot,
+ uint64_t pages_per_clear)
{
- int i;
+ int i, slot;
+ uint64_t from, clear_pages_count;
for (i = 0; i < slots; i++) {
- int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
-
- kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
+ slot = MEMSTRESS_MEM_SLOT_INDEX + i;
+ from = 0;
+ clear_pages_count = pages_per_clear;
+
+ while (from < pages_per_slot) {
+ if (from + clear_pages_count > pages_per_slot)
+ clear_pages_count = pages_per_slot - from;
+ kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], from,
+ clear_pages_count);
+ from += clear_pages_count;
+ }
}
+
}
unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot)
--
2.40.0.634.g4ca3ef3211-goog
Move mmu_lock lock and unlock calls from common code in
kvm_clear_dirty_log_protect() to arch specific code in
kvm_arch_mmu_enable_log_dirty_pt_masked(). None of the other code inside
the for loop of kvm_arch_mmu_enable_log_dirty_pt_masked() needs mmu_lock
exclusivity apart from the arch specific API call.
Future commits will change clear dirty log operations under mmu read
lock instead of write lock for ARM and, potentially, x86 architectures.
No functional changes intended.
Signed-off-by: Vipin Sharma <[email protected]>
---
arch/arm64/kvm/mmu.c | 2 ++
arch/mips/kvm/mmu.c | 2 ++
arch/riscv/kvm/mmu.c | 2 ++
arch/x86/kvm/mmu/mmu.c | 3 +++
virt/kvm/dirty_ring.c | 2 --
virt/kvm/kvm_main.c | 4 ----
6 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 7113587222ff..dc1c9059604e 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1002,7 +1002,9 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn_offset, unsigned long mask)
{
+ write_lock(&kvm->mmu_lock);
kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
+ write_unlock(&kvm->mmu_lock);
}
static void kvm_send_hwpoison_signal(unsigned long address, short lsb)
diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
index e8c08988ed37..b8d4723d197e 100644
--- a/arch/mips/kvm/mmu.c
+++ b/arch/mips/kvm/mmu.c
@@ -415,11 +415,13 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn_offset, unsigned long mask)
{
+ spin_lock(&kvm->mmu_lock);
gfn_t base_gfn = slot->base_gfn + gfn_offset;
gfn_t start = base_gfn + __ffs(mask);
gfn_t end = base_gfn + __fls(mask);
kvm_mips_mkclean_gpa_pt(kvm, start, end);
+ spin_unlock(&kvm->mmu_lock);
}
/*
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 78211aed36fa..425fa11dcf9c 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -395,11 +395,13 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
gfn_t gfn_offset,
unsigned long mask)
{
+ spin_lock(&kvm->mmu_lock);
phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
phys_addr_t start = (base_gfn + __ffs(mask)) << PAGE_SHIFT;
phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
gstage_wp_range(kvm, start, end);
+ spin_unlock(&kvm->mmu_lock);
}
void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 144c5a01cd77..f1dc549b01cb 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1367,6 +1367,7 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn_offset, unsigned long mask)
{
+ write_lock(&kvm->mmu_lock);
/*
* Huge pages are NOT write protected when we start dirty logging in
* initially-all-set mode; must write protect them here so that they
@@ -1397,6 +1398,8 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
kvm_mmu_clear_dirty_pt_masked(kvm, slot, gfn_offset, mask);
else
kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
+
+ write_unlock(&kvm->mmu_lock);
}
int kvm_cpu_dirty_log_size(void)
diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
index c1cd7dfe4a90..d894c58d2152 100644
--- a/virt/kvm/dirty_ring.c
+++ b/virt/kvm/dirty_ring.c
@@ -66,9 +66,7 @@ static void kvm_reset_dirty_gfn(struct kvm *kvm, u32 slot, u64 offset, u64 mask)
if (!memslot || (offset + __fls(mask)) >= memslot->npages)
return;
- KVM_MMU_LOCK(kvm);
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot, offset, mask);
- KVM_MMU_UNLOCK(kvm);
}
int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f40b72eb0e7b..378c40e958b6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2157,7 +2157,6 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
memset(dirty_bitmap_buffer, 0, n);
- KVM_MMU_LOCK(kvm);
for (i = 0; i < n / sizeof(long); i++) {
unsigned long mask;
gfn_t offset;
@@ -2173,7 +2172,6 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
offset, mask);
}
- KVM_MMU_UNLOCK(kvm);
}
if (flush)
@@ -2268,7 +2266,6 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
return -EFAULT;
- KVM_MMU_LOCK(kvm);
for (offset = log->first_page, i = offset / BITS_PER_LONG,
n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--;
i++, offset += BITS_PER_LONG) {
@@ -2291,7 +2288,6 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
offset, mask);
}
}
- KVM_MMU_UNLOCK(kvm);
if (flush)
kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
--
2.40.0.634.g4ca3ef3211-goog
Fetch read and write accesses of pages from guest code and print count
across all vCPUs in dirty_log_perf_test.
This data provides progress made by vCPUs during dirty logging
operations. Since, vCPUs execute in lockstep with userspace dirty log
iterations, this metric is not very interesting. However, in future
commits when dirty_log_perf_test can execute vCPUs independently from
dirty log iterations then this metric can give good measure of vCPUs
performance during dirty logging.
Signed-off-by: Vipin Sharma <[email protected]>
---
.../selftests/kvm/dirty_log_perf_test.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
index 338f03a4a550..0a08a3d21123 100644
--- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
@@ -12,6 +12,7 @@
#include <stdlib.h>
#include <time.h>
#include <pthread.h>
+#include <stdatomic.h>
#include <linux/bitmap.h>
#include "kvm_util.h"
@@ -66,17 +67,22 @@ static u64 dirty_log_manual_caps;
static bool host_quit;
static int iteration;
static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
+static atomic_ullong total_reads;
+static atomic_ullong total_writes;
static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
{
struct kvm_vcpu *vcpu = vcpu_args->vcpu;
int vcpu_idx = vcpu_args->vcpu_idx;
uint64_t pages_count = 0;
+ uint64_t reads = 0;
+ uint64_t writes = 0;
struct kvm_run *run;
struct timespec start;
struct timespec ts_diff;
struct timespec total = (struct timespec){0};
struct timespec avg;
+ struct ucall uc = {};
int ret;
run = vcpu->run;
@@ -89,7 +95,7 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
ts_diff = timespec_elapsed(start);
TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
- TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
+ TEST_ASSERT(get_ucall(vcpu, &uc) == UCALL_SYNC,
"Invalid guest sync status: exit_reason=%s\n",
exit_reason_str(run->exit_reason));
@@ -101,6 +107,8 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
if (current_iteration) {
pages_count += vcpu_args->pages;
total = timespec_add(total, ts_diff);
+ reads += uc.args[2];
+ writes += uc.args[3];
pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",
vcpu_idx, current_iteration, ts_diff.tv_sec,
ts_diff.tv_nsec);
@@ -123,6 +131,8 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
vcpu_idx, pages_count, vcpu_last_completed_iteration[vcpu_idx],
total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
+ atomic_fetch_add(&total_reads, reads);
+ atomic_fetch_add(&total_writes, writes);
}
struct test_params {
@@ -176,6 +186,8 @@ static void run_test(enum vm_guest_mode mode, void *arg)
dirty_log_manual_caps);
arch_setup_vm(vm, nr_vcpus);
+ atomic_store(&total_reads, 0);
+ atomic_store(&total_writes, 0);
/* Start the iterations */
iteration = 0;
@@ -295,6 +307,10 @@ static void run_test(enum vm_guest_mode mode, void *arg)
clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
}
+ pr_info("Total pages touched: %llu (Reads: %llu, Writes: %llu)\n",
+ atomic_load(&total_reads) + atomic_load(&total_writes),
+ atomic_load(&total_reads), atomic_load(&total_writes));
+
memstress_free_bitmaps(bitmaps, p->slots);
arch_cleanup_vm(vm);
memstress_destroy_vm(vm);
--
2.40.0.634.g4ca3ef3211-goog
Allow vCPUs to execute independent of dirty log iterations after
initialization is complete. Hide this feature behind the new option
"-j".
This change makes dirty_log_perf_test execute like real world workflows
where guest vCPUs keep on executing while VMM collects dirty logs. Total
pages touched during execution of test will give good estimate of how
vCPUs are performing while dirty logging is enabled.
Signed-off-by: Vipin Sharma <[email protected]>
---
.../selftests/kvm/dirty_log_perf_test.c | 60 ++++++++++++-------
1 file changed, 40 insertions(+), 20 deletions(-)
diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
index 0a08a3d21123..ffdad535fdaa 100644
--- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
@@ -69,6 +69,7 @@ static int iteration;
static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
static atomic_ullong total_reads;
static atomic_ullong total_writes;
+static bool lockstep_iterations;
static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
{
@@ -83,12 +84,16 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
struct timespec total = (struct timespec){0};
struct timespec avg;
struct ucall uc = {};
+ int current_iteration = -1;
int ret;
run = vcpu->run;
while (!READ_ONCE(host_quit)) {
- int current_iteration = READ_ONCE(iteration);
+ if (lockstep_iterations)
+ current_iteration = READ_ONCE(iteration);
+ else
+ current_iteration++;
clock_gettime(CLOCK_MONOTONIC, &start);
ret = _vcpu_run(vcpu);
@@ -118,13 +123,19 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
ts_diff.tv_nsec);
}
- /*
- * Keep running the guest while dirty logging is being disabled
- * (iteration is negative) so that vCPUs are accessing memory
- * for the entire duration of zapping collapsible SPTEs.
- */
- while (current_iteration == READ_ONCE(iteration) &&
- READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {}
+ if (lockstep_iterations) {
+ /*
+ * Keep running the guest while dirty logging is being disabled
+ * (iteration is negative) so that vCPUs are accessing memory
+ * for the entire duration of zapping collapsible SPTEs.
+ */
+ while (current_iteration == READ_ONCE(iteration) &&
+ READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit))
+ ;
+ } else {
+ while (!READ_ONCE(iteration))
+ ;
+ }
}
avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]);
@@ -238,17 +249,19 @@ static void run_test(enum vm_guest_mode mode, void *arg)
clock_gettime(CLOCK_MONOTONIC, &start);
iteration++;
- pr_debug("Starting iteration %d\n", iteration);
- for (i = 0; i < nr_vcpus; i++) {
- while (READ_ONCE(vcpu_last_completed_iteration[i])
- != iteration)
- ;
- }
+ if (lockstep_iterations) {
+ pr_debug("Starting iteration %d\n", iteration);
+ for (i = 0; i < nr_vcpus; i++) {
+ while (READ_ONCE(vcpu_last_completed_iteration[i])
+ != iteration)
+ ;
+ }
- ts_diff = timespec_elapsed(start);
- vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
- pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
- iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
+ ts_diff = timespec_elapsed(start);
+ vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
+ pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
+ iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
+ }
clock_gettime(CLOCK_MONOTONIC, &start);
memstress_get_dirty_log(vm, bitmaps, p->slots);
@@ -365,6 +378,10 @@ static void help(char *name)
" To leave the application task unpinned, drop the final entry:\n\n"
" ./dirty_log_perf_test -v 3 -c 22,23,24\n\n"
" (default: no pinning)\n");
+ printf(" -j: Execute vCPUs independent of dirty log iterations\n"
+ " Independent vCPUs execution will allow them to continuously\n"
+ " dirty memory while main thread is collecting and clearing\n"
+ " dirty logs in the main thread's iterations.\n");
printf(" -k: Specify the chunk size in which dirty memory gets cleared\n"
" in memslots in each iteration. If the size is bigger than\n"
" the memslot size then whole memslot is cleared in one call.\n"
@@ -399,10 +416,10 @@ int main(int argc, char *argv[])
kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
KVM_DIRTY_LOG_INITIALLY_SET);
-
+ lockstep_iterations = true;
guest_modes_append_default();
- while ((opt = getopt(argc, argv, "ab:c:eghi:k:l:m:nop:r:s:v:x:w:")) != -1) {
+ while ((opt = getopt(argc, argv, "ab:c:eghi:jk:l:m:nop:r:s:v:x:w:")) != -1) {
switch (opt) {
case 'a':
p.random_access = true;
@@ -426,6 +443,9 @@ int main(int argc, char *argv[])
case 'i':
p.iterations = atoi_positive("Number of iterations", optarg);
break;
+ case 'j':
+ lockstep_iterations = false;
+ break;
case 'k':
p.clear_chunk_size = parse_size(optarg);
break;
--
2.40.0.634.g4ca3ef3211-goog
Hi Vipin,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 95b9779c1758f03cf494e8550d6249a40089ed1c]
url: https://github.com/intel-lab-lkp/linux/commits/Vipin-Sharma/KVM-selftests-Allow-dirty_log_perf_test-to-clear-dirty-memory-in-chunks/20230422-005708
base: 95b9779c1758f03cf494e8550d6249a40089ed1c
patch link: https://lore.kernel.org/r/20230421165305.804301-8-vipinsh%40google.com
patch subject: [PATCH 7/9] KVM: mmu: Move mmu lock/unlock to arch code for clear dirty log
config: riscv-allyesconfig (https://download.01.org/0day-ci/archive/20230422/[email protected]/config)
compiler: riscv64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/e7505b53d53e3bb5e7f1c43233ef3644673edb75
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Vipin-Sharma/KVM-selftests-Allow-dirty_log_perf_test-to-clear-dirty-memory-in-chunks/20230422-005708
git checkout e7505b53d53e3bb5e7f1c43233ef3644673edb75
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kvm/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
arch/riscv/kvm/mmu.c: In function 'kvm_arch_mmu_enable_log_dirty_pt_masked':
>> arch/riscv/kvm/mmu.c:399:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
399 | phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
| ^~~~~~~~~~~
vim +399 arch/riscv/kvm/mmu.c
c9d57373fc87a3 Anup Patel 2022-07-29 392
9d05c1fee83757 Anup Patel 2021-09-27 393 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
9d05c1fee83757 Anup Patel 2021-09-27 394 struct kvm_memory_slot *slot,
9d05c1fee83757 Anup Patel 2021-09-27 395 gfn_t gfn_offset,
9d05c1fee83757 Anup Patel 2021-09-27 396 unsigned long mask)
9d05c1fee83757 Anup Patel 2021-09-27 397 {
e7505b53d53e3b Vipin Sharma 2023-04-21 398 spin_lock(&kvm->mmu_lock);
9d05c1fee83757 Anup Patel 2021-09-27 @399 phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
9d05c1fee83757 Anup Patel 2021-09-27 400 phys_addr_t start = (base_gfn + __ffs(mask)) << PAGE_SHIFT;
9d05c1fee83757 Anup Patel 2021-09-27 401 phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
9d05c1fee83757 Anup Patel 2021-09-27 402
26708234eb12e7 Anup Patel 2022-05-09 403 gstage_wp_range(kvm, start, end);
e7505b53d53e3b Vipin Sharma 2023-04-21 404 spin_unlock(&kvm->mmu_lock);
9d05c1fee83757 Anup Patel 2021-09-27 405 }
99cdc6c18c2d81 Anup Patel 2021-09-27 406
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
On Fri, Apr 21, 2023 at 12:43 PM kernel test robot <[email protected]> wrote:
>
> Hi Vipin,
>
> All warnings (new ones prefixed by >>):
>
> arch/riscv/kvm/mmu.c: In function 'kvm_arch_mmu_enable_log_dirty_pt_masked':
> >> arch/riscv/kvm/mmu.c:399:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
> 399 | phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
> | ^~~~~~~~~~~
>
>
I will fix it in v2.