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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v2 06/13] tools/xenstore: switch write limiting to use millisecond time base
There is no need to keep struct wrl_timestampt, as it serves the same
purpose as the more simple time base provided by get_now().
Move some more stuff from xenstored_domain.h into xenstored_domain.c
as it is being used nowhere else.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
tools/xenstore/xenstored_core.c | 8 ++---
tools/xenstore/xenstored_core.h | 7 ++--
tools/xenstore/xenstored_domain.c | 56 +++++++++++++------------------
tools/xenstore/xenstored_domain.h | 21 ++----------
4 files changed, 32 insertions(+), 60 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index c5433e5b3f..6be2a3aa42 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -192,7 +192,7 @@ void reopen_log(void)
}
}
-static uint64_t get_now_msec(void)
+uint64_t get_now_msec(void)
{
struct timespec now_ts;
@@ -510,7 +510,6 @@ fail:
static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout)
{
struct connection *conn;
- struct wrl_timestampt now;
uint64_t msecs;
if (fds)
@@ -530,13 +529,12 @@ static void initialize_fds(int *p_sock_pollfd_idx, int
*ptimeout)
xce_pollfd_idx = set_fd(xenevtchn_fd(xce_handle),
POLLIN|POLLPRI);
- wrl_gettime_now(&now);
- wrl_log_periodic(now);
msecs = get_now_msec();
+ wrl_log_periodic(msecs);
list_for_each_entry(conn, &connections, list) {
if (conn->domain) {
- wrl_check_timeout(conn->domain, now, ptimeout);
+ wrl_check_timeout(conn->domain, msecs, ptimeout);
check_event_timeout(conn, msecs, ptimeout);
if (conn_can_read(conn) ||
(conn_can_write(conn) &&
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 92d5b50f3c..84a611cbb5 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -47,10 +47,6 @@
/* DEFAULT_BUFFER_SIZE should be large enough for each errno string. */
#define DEFAULT_BUFFER_SIZE 16
-typedef int32_t wrl_creditt;
-#define WRL_CREDIT_MAX (1000*1000*1000)
-/* ^ satisfies non-overflow condition for wrl_xfer_credit */
-
struct xs_state_connection;
struct buffered_data
@@ -320,6 +316,9 @@ extern bool keep_orphans;
extern unsigned int timeout_watch_event_msec;
+/* Get internal time in milliseconds. */
+uint64_t get_now_msec(void);
+
/* Map the kernel's xenstore page. */
void *xenbus_map(void);
void unmap_xenbus(void *interface);
diff --git a/tools/xenstore/xenstored_domain.c
b/tools/xenstore/xenstored_domain.c
index 0a8353dad5..2fb142c5b3 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -99,6 +99,8 @@ struct quota soft_quotas[ACC_N] = {
},
};
+typedef int32_t wrl_creditt;
+
struct domain
{
/* The id of this domain */
@@ -139,7 +141,7 @@ struct domain
/* write rate limit */
wrl_creditt wrl_credit; /* [ -wrl_config_writecost, +_dburst ] */
- struct wrl_timestampt wrl_timestamp;
+ uint64_t wrl_timestamp;
bool wrl_delay_logged;
};
@@ -159,6 +161,17 @@ struct changed_domain
static struct hashtable *domhash;
+/* Write rate limiting */
+
+/* Satisfies non-overflow condition for wrl_xfer_credit. */
+#define WRL_CREDIT_MAX (1000*1000*1000)
+#define WRL_FACTOR 1000 /* for fixed-point arithmetic */
+#define WRL_RATE 200
+#define WRL_DBURST 10
+#define WRL_GBURST 1000
+#define WRL_NEWDOMS 5
+#define WRL_LOGEVERY 120 /* seconds */
+
static wrl_creditt wrl_config_writecost = WRL_FACTOR;
static wrl_creditt wrl_config_rate = WRL_RATE * WRL_FACTOR;
static wrl_creditt wrl_config_dburst = WRL_DBURST * WRL_FACTOR;
@@ -178,19 +191,6 @@ do { \
trace("wrl: " __VA_ARGS__); \
} while (0)
-void wrl_gettime_now(struct wrl_timestampt *now_wt)
-{
- struct timespec now_ts;
- int r;
-
- r = clock_gettime(CLOCK_MONOTONIC, &now_ts);
- if (r)
- barf_perror("Could not find time (clock_gettime failed)");
-
- now_wt->sec = now_ts.tv_sec;
- now_wt->msec = now_ts.tv_nsec / 1000000;
-}
-
static void wrl_xfer_credit(wrl_creditt *debit, wrl_creditt debit_floor,
wrl_creditt *credit, wrl_creditt credit_ceil)
/*
@@ -217,7 +217,7 @@ static void wrl_xfer_credit(wrl_creditt *debit,
wrl_creditt debit_floor,
static void wrl_domain_new(struct domain *domain)
{
domain->wrl_credit = 0;
- wrl_gettime_now(&domain->wrl_timestamp);
+ domain->wrl_timestamp = get_now_msec();
wrl_ndomains++;
/* Steal up to DBURST from the reserve */
wrl_xfer_credit(&wrl_reserve, -wrl_config_newdoms_dburst,
@@ -236,7 +236,7 @@ static void wrl_domain_destroy(struct domain *domain)
&wrl_reserve, wrl_config_dburst);
}
-static void wrl_credit_update(struct domain *domain, struct wrl_timestampt now)
+static void wrl_credit_update(struct domain *domain, uint64_t now)
{
/*
* We want to calculate
@@ -245,18 +245,12 @@ static void wrl_credit_update(struct domain *domain,
struct wrl_timestampt now)
* To avoid rounding errors from constantly adding small
* amounts of credit, we only add credit for whole milliseconds.
*/
- long seconds = now.sec - domain->wrl_timestamp.sec;
- long milliseconds = now.msec - domain->wrl_timestamp.msec;
long msec;
int64_t denom, num;
wrl_creditt surplus;
- seconds = MIN(seconds, 1000*1000); /* arbitrary, prevents overflow */
- msec = seconds * 1000 + milliseconds;
-
- if (msec < 0)
- /* shouldn't happen with CLOCK_MONOTONIC */
- msec = 0;
+ /* Prevent overflow by limiting to 32 bits. */
+ msec = MIN(now - domain->wrl_timestamp, 1000 * 1000 * 1000);
/* 32x32 -> 64 cannot overflow */
denom = (int64_t)msec * wrl_config_rate;
@@ -288,9 +282,7 @@ static void wrl_credit_update(struct domain *domain, struct
wrl_timestampt now)
(long)wrl_reserve, (long)surplus);
}
-void wrl_check_timeout(struct domain *domain,
- struct wrl_timestampt now,
- int *ptimeout)
+void wrl_check_timeout(struct domain *domain, uint64_t now, int *ptimeout)
{
uint64_t num, denom;
int wakeup;
@@ -327,13 +319,13 @@ void wrl_check_timeout(struct domain *domain,
void wrl_apply_debit_actual(struct domain *domain)
{
- struct wrl_timestampt now;
+ uint64_t now;
if (!domain || !domain_is_unprivileged(domain->conn))
/* sockets and privileged domain escape the write rate limit */
return;
- wrl_gettime_now(&now);
+ now = get_now_msec();
wrl_credit_update(domain, now);
domain->wrl_credit -= wrl_config_writecost;
@@ -348,14 +340,14 @@ void wrl_apply_debit_actual(struct domain *domain)
} else if (!wrl_log_last_warning) {
WRL_LOG(now, "rate limiting restarts\n");
}
- wrl_log_last_warning = now.sec;
+ wrl_log_last_warning = now / 1000;
}
}
-void wrl_log_periodic(struct wrl_timestampt now)
+void wrl_log_periodic(uint64_t now)
{
if (wrl_log_last_warning &&
- (now.sec - wrl_log_last_warning) > WRL_LOGEVERY) {
+ (now / 1000 - wrl_log_last_warning) > WRL_LOGEVERY) {
WRL_LOG(now, "not in force recently\n");
wrl_log_last_warning = 0;
}
diff --git a/tools/xenstore/xenstored_domain.h
b/tools/xenstore/xenstored_domain.h
index 8cd69d42ab..f9ee0bd141 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -145,27 +145,10 @@ void domain_reset_global_acc(void);
bool domain_max_chk(const struct connection *conn, unsigned int what,
unsigned int val);
-/* Write rate limiting */
-
-#define WRL_FACTOR 1000 /* for fixed-point arithmetic */
-#define WRL_RATE 200
-#define WRL_DBURST 10
-#define WRL_GBURST 1000
-#define WRL_NEWDOMS 5
-#define WRL_LOGEVERY 120 /* seconds */
-
-struct wrl_timestampt {
- time_t sec;
- int msec;
-};
-
extern long wrl_ntransactions;
-void wrl_gettime_now(struct wrl_timestampt *now_ts);
-void wrl_check_timeout(struct domain *domain,
- struct wrl_timestampt now,
- int *ptimeout);
-void wrl_log_periodic(struct wrl_timestampt now);
+void wrl_check_timeout(struct domain *domain, uint64_t now, int *ptimeout);
+void wrl_log_periodic(uint64_t now);
void wrl_apply_debit_direct(struct connection *conn);
void wrl_apply_debit_trans_commit(struct connection *conn);
--
2.35.3
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