From d0b5b7ce48294d4525fbbda9385faa7900cd39ba Mon Sep 17 00:00:00 2001 From: Thomas Schoebel-Theuer Date: Tue, 20 Nov 2012 09:09:33 +0100 Subject: [PATCH] brick_say: allow delaying callers upon overflow --- brick_say.c | 54 +++++++++++++++++++++++++++++++++++----------- brick_say.h | 1 + sy_old/mars_proc.c | 1 + 3 files changed, 43 insertions(+), 13 deletions(-) diff --git a/brick_say.c b/brick_say.c index d575dffa..ab4ce5f4 100644 --- a/brick_say.c +++ b/brick_say.c @@ -28,6 +28,7 @@ #define SAY_ORDER 0 #define SAY_BUFMAX (PAGE_SIZE << SAY_ORDER) +#define SAY_BUF_LIMIT (SAY_BUFMAX - 1500) #define MAX_FILELEN 16 #define MAX_IDS 1000 @@ -44,6 +45,13 @@ int brick_say_syslog_min = 1; EXPORT_SYMBOL_GPL(brick_say_syslog_min); int brick_say_syslog_max = -1; EXPORT_SYMBOL_GPL(brick_say_syslog_max); +int delay_say_on_overflow = +#ifdef CONFIG_MARS_DEBUG + 1; +#else + 0; +#endif +EXPORT_SYMBOL_GPL(delay_say_on_overflow); struct say_channel { @@ -59,6 +67,7 @@ struct say_channel { int ch_status_written; int ch_id_max; void *ch_ids[MAX_IDS]; + wait_queue_head_t ch_progress; }; struct say_channel *default_channel = NULL; @@ -74,6 +83,19 @@ static DECLARE_WAIT_QUEUE_HEAD(say_event); bool say_dirty = false; +static +void wait_channel(struct say_channel *ch, int class) +{ + if (delay_say_on_overflow && ch->ch_index[class] > SAY_BUF_LIMIT) { + bool use_atomic = (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK | NMI_MASK)) != 0 || in_atomic() || irqs_disabled(); + if (!use_atomic) { + say_dirty = true; + wake_up_interruptible(&say_event); + wait_event_interruptible_timeout(ch->ch_progress, ch->ch_index[class] < SAY_BUF_LIMIT, HZ / 10); + } + } +} + static struct say_channel *find_channel(const void *id) { @@ -265,6 +287,7 @@ struct say_channel *_make_channel(const char *name) if (unlikely(!res)) { goto done; } + init_waitqueue_head(&res->ch_progress); res->ch_name = kstrdup(name, mode); if (unlikely(!res->ch_name)) { kfree(res); @@ -335,14 +358,16 @@ static void _say(struct say_channel *ch, int class, va_list args, bool use_args, const char *fmt, ...) { char *start; + int offset; int rest; int written; if (!ch) return; - start = ch->ch_buf[class][0] + ch->ch_index[class]; - rest = SAY_BUFMAX - 1 - ch->ch_index[class]; + offset = ch->ch_index[class]; + start = ch->ch_buf[class][0] + offset; + rest = SAY_BUFMAX - 1 - offset; if (unlikely(rest <= 0)) { ch->ch_overflow[class]++; return; @@ -379,6 +404,7 @@ void say_to(struct say_channel *ch, int class, const char *fmt, ...) if (likely(ch)) { if (likely(class >= 0 && class < MAX_SAY_CLASS)) { + wait_channel(ch, class); spin_lock_irqsave(&ch->ch_lock[class], flags); va_start(args, fmt); @@ -392,6 +418,7 @@ void say_to(struct say_channel *ch, int class, const char *fmt, ...) ch = default_channel; if (likely(ch)) { class = SAY_TOTAL; + wait_channel(ch, class); spin_lock_irqsave(&ch->ch_lock[class], flags); va_start(args, fmt); @@ -425,6 +452,7 @@ void brick_say_to(struct say_channel *ch, int class, bool dump, const char *pref if (likely(ch)) { channel_name = ch->ch_name; if (likely(class >= 0 && class < MAX_SAY_CLASS)) { + wait_channel(ch, class); spin_lock_irqsave(&ch->ch_lock[class], flags); _say(ch, class, NULL, true, @@ -445,6 +473,7 @@ void brick_say_to(struct say_channel *ch, int class, bool dump, const char *pref ch = default_channel; if (likely(ch)) { + wait_channel(ch, SAY_TOTAL); spin_lock_irqsave(&ch->ch_lock[SAY_TOTAL], flags); _say(ch, SAY_TOTAL, NULL, true, @@ -564,16 +593,6 @@ void treat_channel(struct say_channel *ch, int class) char *tmp; unsigned long flags; - for (transact = 0; transact < 2; transact++) { - if (unlikely(!ch->ch_filp[class][transact])) { - char *filename = _make_filename(ch, class, transact, transact); - if (likely(filename)) { - try_open_file(&ch->ch_filp[class][transact], filename, transact); - kfree(filename); - } - } - } - spin_lock_irqsave(&ch->ch_lock[class], flags); buf = ch->ch_buf[class][0]; @@ -587,15 +606,24 @@ void treat_channel(struct say_channel *ch, int class) spin_unlock_irqrestore(&ch->ch_lock[class], flags); + wake_up_interruptible(&ch->ch_progress); + ch->ch_status_written += len; out_to_syslog(class, buf, len); for (transact = 0; transact < 2; transact++) { + if (unlikely(!ch->ch_filp[class][transact])) { + char *filename = _make_filename(ch, class, transact, transact); + if (likely(filename)) { + try_open_file(&ch->ch_filp[class][transact], filename, transact); + kfree(filename); + } + } out_to_file(ch->ch_filp[class][transact], buf, len); } if (unlikely(overflow > 0)) { struct timespec now = CURRENT_TIME; - len = snprintf(buf, SAY_BUFMAX, "%ld.%09ld OVERFLOW %d times\n", now.tv_sec, now.tv_nsec, overflow); + len = snprintf(buf, SAY_BUFMAX, "%ld.%09ld %s %d OVERFLOW %d times\n", now.tv_sec, now.tv_nsec, ch->ch_name, class, overflow); ch->ch_status_written += len; out_to_syslog(class, buf, len); for (transact = 0; transact < 2; transact++) { diff --git a/brick_say.h b/brick_say.h index 15a6d0fe..490751df 100644 --- a/brick_say.h +++ b/brick_say.h @@ -6,6 +6,7 @@ extern int brick_say_syslog_min; extern int brick_say_syslog_max; +extern int delay_say_on_overflow; // printk() replacements diff --git a/sy_old/mars_proc.c b/sy_old/mars_proc.c index 8f7d0449..c95f7196 100644 --- a/sy_old/mars_proc.c +++ b/sy_old/mars_proc.c @@ -147,6 +147,7 @@ ctl_table mars_table[] = { }, INT_ENTRY("syslog_min_class", brick_say_syslog_min, 0600), INT_ENTRY("syslog_max_class", brick_say_syslog_max, 0600), + INT_ENTRY("delay_say_on_overflow",delay_say_on_overflow, 0600), INT_ENTRY("percent_mem_limit_kb", mars_mem_percent, 0600), INT_ENTRY("logger_mem_used_kb", trans_logger_mem_usage, 0400), INT_ENTRY("raw_mem_used_kb", brick_global_block_used,0400),