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[Qemu-devel] [PATCH v4] migration: change blocktime type to uint32_t
From: |
Alexey Perevalov |
Subject: |
[Qemu-devel] [PATCH v4] migration: change blocktime type to uint32_t |
Date: |
Thu, 22 Feb 2018 11:45:07 +0300 |
Initially int64_t was used, but on PowerPC architecture,
clang doesn't have atomic_*_8 function, so it produces
link time error.
QEMU is working with time as with 64bit value, but by
fact 32 bit is enough with CLOCK_REALTIME. In this case
blocktime will keep only 1200 hours time interval.
Signed-off-by: Alexey Perevalov <address@hidden>
Acked-by: Eric Blake <address@hidden>
---
hmp.c | 4 ++--
migration/postcopy-ram.c | 52 ++++++++++++++++++++++++++++--------------------
migration/trace-events | 4 ++--
qapi/migration.json | 4 ++--
4 files changed, 36 insertions(+), 28 deletions(-)
diff --git a/hmp.c b/hmp.c
index be091e0..ec90043 100644
--- a/hmp.c
+++ b/hmp.c
@@ -267,7 +267,7 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
}
if (info->has_postcopy_blocktime) {
- monitor_printf(mon, "postcopy blocktime: %" PRId64 "\n",
+ monitor_printf(mon, "postcopy blocktime: %u\n",
info->postcopy_blocktime);
}
@@ -275,7 +275,7 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
Visitor *v;
char *str;
v = string_output_visitor_new(false, &str);
- visit_type_int64List(v, NULL, &info->postcopy_vcpu_blocktime, NULL);
+ visit_type_uint32List(v, NULL, &info->postcopy_vcpu_blocktime, NULL);
visit_complete(v, &str);
monitor_printf(mon, "postcopy vcpu blocktime: %s\n", str);
g_free(str);
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 05475e0..c46225c 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -63,16 +63,17 @@ struct PostcopyDiscardState {
typedef struct PostcopyBlocktimeContext {
/* time when page fault initiated per vCPU */
- int64_t *page_fault_vcpu_time;
+ uint32_t *page_fault_vcpu_time;
/* page address per vCPU */
uintptr_t *vcpu_addr;
- int64_t total_blocktime;
+ uint32_t total_blocktime;
/* blocktime per vCPU */
- int64_t *vcpu_blocktime;
+ uint32_t *vcpu_blocktime;
/* point in time when last page fault was initiated */
- int64_t last_begin;
+ uint32_t last_begin;
/* number of vCPU are suspended */
int smp_cpus_down;
+ uint64_t start_time;
/*
* Handler for exit event, necessary for
@@ -99,22 +100,23 @@ static void migration_exit_cb(Notifier *n, void *data)
static struct PostcopyBlocktimeContext *blocktime_context_new(void)
{
PostcopyBlocktimeContext *ctx = g_new0(PostcopyBlocktimeContext, 1);
- ctx->page_fault_vcpu_time = g_new0(int64_t, smp_cpus);
+ ctx->page_fault_vcpu_time = g_new0(uint32_t, smp_cpus);
ctx->vcpu_addr = g_new0(uintptr_t, smp_cpus);
- ctx->vcpu_blocktime = g_new0(int64_t, smp_cpus);
+ ctx->vcpu_blocktime = g_new0(uint32_t, smp_cpus);
ctx->exit_notifier.notify = migration_exit_cb;
+ ctx->start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
qemu_add_exit_notifier(&ctx->exit_notifier);
return ctx;
}
-static int64List *get_vcpu_blocktime_list(PostcopyBlocktimeContext *ctx)
+static uint32List *get_vcpu_blocktime_list(PostcopyBlocktimeContext *ctx)
{
- int64List *list = NULL, *entry = NULL;
+ uint32List *list = NULL, *entry = NULL;
int i;
for (i = smp_cpus - 1; i >= 0; i--) {
- entry = g_new0(int64List, 1);
+ entry = g_new0(uint32List, 1);
entry->value = ctx->vcpu_blocktime[i];
entry->next = list;
list = entry;
@@ -145,7 +147,7 @@ void fill_destination_postcopy_migration_info(MigrationInfo
*info)
info->postcopy_vcpu_blocktime = get_vcpu_blocktime_list(bc);
}
-static uint64_t get_postcopy_total_blocktime(void)
+static uint32_t get_postcopy_total_blocktime(void)
{
MigrationIncomingState *mis = migration_incoming_get_current();
PostcopyBlocktimeContext *bc = mis->blocktime_ctx;
@@ -610,6 +612,13 @@ static int get_mem_fault_cpu_index(uint32_t pid)
return -1;
}
+static uint32_t get_low_time_offset(PostcopyBlocktimeContext *dc)
+{
+ int64_t start_time_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) -
+ dc->start_time;
+ return start_time_offset < 1 ? 1 : start_time_offset & UINT32_MAX;
+}
+
/*
* This function is being called when pagefault occurs. It
* tracks down vCPU blocking time.
@@ -624,7 +633,7 @@ static void mark_postcopy_blocktime_begin(uintptr_t addr,
uint32_t ptid,
int cpu, already_received;
MigrationIncomingState *mis = migration_incoming_get_current();
PostcopyBlocktimeContext *dc = mis->blocktime_ctx;
- int64_t now_ms;
+ uint32_t low_time_offset;
if (!dc || ptid == 0) {
return;
@@ -634,14 +643,14 @@ static void mark_postcopy_blocktime_begin(uintptr_t addr,
uint32_t ptid,
return;
}
- now_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ low_time_offset = get_low_time_offset(dc);
if (dc->vcpu_addr[cpu] == 0) {
atomic_inc(&dc->smp_cpus_down);
}
- atomic_xchg__nocheck(&dc->last_begin, now_ms);
- atomic_xchg__nocheck(&dc->page_fault_vcpu_time[cpu], now_ms);
- atomic_xchg__nocheck(&dc->vcpu_addr[cpu], addr);
+ atomic_xchg(&dc->last_begin, low_time_offset);
+ atomic_xchg(&dc->page_fault_vcpu_time[cpu], low_time_offset);
+ atomic_xchg(&dc->vcpu_addr[cpu], addr);
/* check it here, not at the begining of the function,
* due to, check could accur early than bitmap_set in
@@ -688,22 +697,20 @@ static void mark_postcopy_blocktime_end(uintptr_t addr)
MigrationIncomingState *mis = migration_incoming_get_current();
PostcopyBlocktimeContext *dc = mis->blocktime_ctx;
int i, affected_cpu = 0;
- int64_t now_ms;
bool vcpu_total_blocktime = false;
- int64_t read_vcpu_time;
+ uint32_t read_vcpu_time, low_time_offset;
if (!dc) {
return;
}
- now_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
-
+ low_time_offset = get_low_time_offset(dc);
/* lookup cpu, to clear it,
* that algorithm looks straighforward, but it's not
* optimal, more optimal algorithm is keeping tree or hash
* where key is address value is a list of */
for (i = 0; i < smp_cpus; i++) {
- uint64_t vcpu_blocktime = 0;
+ uint32_t vcpu_blocktime = 0;
read_vcpu_time = atomic_fetch_add(&dc->page_fault_vcpu_time[i], 0);
if (atomic_fetch_add(&dc->vcpu_addr[i], 0) != addr ||
@@ -711,7 +718,7 @@ static void mark_postcopy_blocktime_end(uintptr_t addr)
continue;
}
atomic_xchg__nocheck(&dc->vcpu_addr[i], 0);
- vcpu_blocktime = now_ms - read_vcpu_time;
+ vcpu_blocktime = low_time_offset - read_vcpu_time;
affected_cpu += 1;
/* we need to know is that mark_postcopy_end was due to
* faulted page, another possible case it's prefetched
@@ -726,7 +733,8 @@ static void mark_postcopy_blocktime_end(uintptr_t addr)
atomic_sub(&dc->smp_cpus_down, affected_cpu);
if (vcpu_total_blocktime) {
- dc->total_blocktime += now_ms - atomic_fetch_add(&dc->last_begin, 0);
+ dc->total_blocktime += low_time_offset - atomic_fetch_add(
+ &dc->last_begin, 0);
}
trace_mark_postcopy_blocktime_end(addr, dc, dc->total_blocktime,
affected_cpu);
diff --git a/migration/trace-events b/migration/trace-events
index 59b1a2d..def03c4 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -115,8 +115,8 @@ process_incoming_migration_co_end(int ret, int ps) "ret=%d
postcopy-state=%d"
process_incoming_migration_co_postcopy_end_main(void) ""
migration_set_incoming_channel(void *ioc, const char *ioctype) "ioc=%p
ioctype=%s"
migration_set_outgoing_channel(void *ioc, const char *ioctype, const char
*hostname, void *err) "ioc=%p ioctype=%s hostname=%s err=%p"
-mark_postcopy_blocktime_begin(uint64_t addr, void *dd, int64_t time, int cpu,
int received) "addr: 0x%" PRIx64 ", dd: %p, time: %" PRId64 ", cpu: %d,
already_received: %d"
-mark_postcopy_blocktime_end(uint64_t addr, void *dd, int64_t time, int
affected_cpu) "addr: 0x%" PRIx64 ", dd: %p, time: %" PRId64 ", affected_cpu: %d"
+mark_postcopy_blocktime_begin(uint64_t addr, void *dd, uint32_t time, int cpu,
int received) "addr: 0x%" PRIx64 ", dd: %p, time: %u, cpu: %d,
already_received: %d"
+mark_postcopy_blocktime_end(uint64_t addr, void *dd, uint32_t time, int
affected_cpu) "addr: 0x%" PRIx64 ", dd: %p, time: %u, affected_cpu: %d"
# migration/rdma.c
qemu_rdma_accept_incoming_migration(void) ""
diff --git a/qapi/migration.json b/qapi/migration.json
index 90d125c..c4737f8 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -175,8 +175,8 @@
'*setup-time': 'int',
'*cpu-throttle-percentage': 'int',
'*error-desc': 'str',
- '*postcopy-blocktime' : 'int64',
- '*postcopy-vcpu-blocktime': ['int64']} }
+ '*postcopy-blocktime' : 'uint32',
+ '*postcopy-vcpu-blocktime': ['uint32']} }
##
# @query-migrate:
--
2.7.4