From 26cf03554a7583301853f473abe37699a28cb230 Mon Sep 17 00:00:00 2001 From: "kaf24@localhost.localdomain" Date: Fri, 27 Oct 2006 18:46:20 +0100 Subject: [PATCH] [XEN] Implement rate-limited logging. Taken from Andi Kleen's rate limit in the Linux kernel. This keeps large amounts of prints in the HV down. Signed-off-by: Steven Rostedt --- xen/arch/x86/mm.c | 9 ++++--- xen/drivers/char/console.c | 55 ++++++++++++++++++++++++++++++++++++++ xen/include/xen/lib.h | 2 ++ 3 files changed, 63 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index f5098d9038..5f3292ac38 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -109,9 +109,12 @@ #include #ifdef VERBOSE -#define MEM_LOG(_f, _a...) \ - printk("DOM%u: (file=mm.c, line=%d) " _f "\n", \ - current->domain->domain_id , __LINE__ , ## _a ) +#define MEM_LOG(_f, _a...) \ + do { \ + if ( printk_ratelimit() ) \ + printk("DOM%u: (file=mm.c, line=%d) " _f "\n", \ + current->domain->domain_id , __LINE__ , ## _a ); \ + } while (0) #else #define MEM_LOG(_f, _a...) ((void)0) #endif diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c index 235d6fefd8..e6a89016b0 100644 --- a/xen/drivers/char/console.c +++ b/xen/drivers/char/console.c @@ -4,6 +4,10 @@ * Emergency console I/O for Xen and the domain-0 guest OS. * * Copyright (c) 2002-2004, K A Fraser. + * + * Added printf_ratelimit + * Taken from Linux - Author: Andi Kleen (net_ratelimit) + * Ported to Xen - Steven Rostedt - Red Hat */ #include @@ -26,6 +30,7 @@ #include #include #include +#include /* console: comma-separated list of console outputs. */ static char opt_console[30] = OPT_CONSOLE_STR; @@ -448,6 +453,56 @@ int console_getc(void) return serial_getc(sercon_handle); } +/* + * printk rate limiting, lifted from Linux. + * + * This enforces a rate limit: not more than one kernel message + * every printk_ratelimit_ms (millisecs). + */ +int __printk_ratelimit(int ratelimit_ms, int ratelimit_burst) +{ + static DEFINE_SPINLOCK(ratelimit_lock); + static unsigned long toks = 10 * 5 * 1000; + static unsigned long last_msg; + static int missed; + unsigned long flags; + unsigned long long now = NOW(); /* ns */ + unsigned long ms; + + do_div(now, 1000000); + ms = (unsigned long)now; + + spin_lock_irqsave(&ratelimit_lock, flags); + toks += ms - last_msg; + last_msg = ms; + if ( toks > (ratelimit_burst * ratelimit_ms)) + toks = ratelimit_burst * ratelimit_ms; + if ( toks >= ratelimit_ms ) + { + int lost = missed; + missed = 0; + toks -= ratelimit_ms; + spin_unlock_irqrestore(&ratelimit_lock, flags); + if ( lost ) + printk("printk: %d messages suppressed.\n", lost); + return 1; + } + missed++; + spin_unlock_irqrestore(&ratelimit_lock, flags); + return 0; +} + +/* minimum time in ms between messages */ +int printk_ratelimit_ms = 5 * 1000; + +/* number of messages we send before ratelimiting */ +int printk_ratelimit_burst = 10; + +int printk_ratelimit(void) +{ + return __printk_ratelimit(printk_ratelimit_ms, + printk_ratelimit_burst); +} /* * ************************************************************** diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h index f333c3f14b..8af65e1ed8 100644 --- a/xen/include/xen/lib.h +++ b/xen/include/xen/lib.h @@ -56,6 +56,8 @@ extern void printk(const char *format, ...) extern void panic(const char *format, ...) __attribute__ ((format (printf, 1, 2))); extern long vm_assist(struct domain *, unsigned int, unsigned int); +extern int __printk_ratelimit(int ratelimit_ms, int ratelimit_burst); +extern int printk_ratelimit(void); /* vsprintf.c */ extern int sprintf(char * buf, const char * fmt, ...) -- 2.30.2