LGTM,
Jarno
Acked-by: Jarno Rajahalme <jrajaha...@nicira.com>
> On Apr 30, 2014, at 2:35 PM, Ben Pfaff <b...@nicira.com> wrote:
>
> The poll_loop code has a feature that, when turned on manually or
> automatically (due to high CPU use), logs the source file and line number
> of the code that caused a thread to wake up from poll(). Until now, when
> a function calls seq_wait(), the source file and line number logged was
> the code inside seq_wait(). seq_wait() has many callers, so that
> information is not as useful as it could be. This commit changes the
> source file and line number used to be that of seq_wait()'s caller.
>
> I found this useful for debugging.
>
> Signed-off-by: Ben Pfaff <b...@nicira.com>
> ---
> lib/seq.c | 20 ++++++++++++--------
> lib/seq.h | 7 +++++--
> 2 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/lib/seq.c b/lib/seq.c
> index 7a34244..452d683 100644
> --- a/lib/seq.c
> +++ b/lib/seq.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (c) 2013 Nicira, Inc.
> + * Copyright (c) 2013, 2014 Nicira, Inc.
> *
> * Licensed under the Apache License, Version 2.0 (the "License");
> * you may not use this file except in compliance with the License.
> @@ -125,7 +125,7 @@ seq_read(const struct seq *seq)
> }
>
> static void
> -seq_wait__(struct seq *seq, uint64_t value)
> +seq_wait__(struct seq *seq, uint64_t value, const char *where)
> OVS_REQUIRES(seq_mutex)
> {
> unsigned int id = ovsthread_id_self();
> @@ -137,7 +137,7 @@ seq_wait__(struct seq *seq, uint64_t value)
> if (waiter->value != value) {
> /* The current value is different from the value we've already
> * waited for, */
> - poll_immediate_wake();
> + poll_immediate_wake_at(where);
> } else {
> /* Already waiting on 'value', nothing more to do. */
> }
> @@ -154,7 +154,7 @@ seq_wait__(struct seq *seq, uint64_t value)
> list_push_back(&waiter->thread->waiters, &waiter->list_node);
>
> if (!waiter->thread->waiting) {
> - latch_wait(&waiter->thread->latch);
> + latch_wait_at(&waiter->thread->latch, where);
> waiter->thread->waiting = true;
> }
> }
> @@ -165,18 +165,22 @@ seq_wait__(struct seq *seq, uint64_t value)
> *
> * seq_read() and seq_wait() can be used together to yield a race-free wakeup
> * when an object changes, even without an ability to lock the object. See
> - * Usage in seq.h for details. */
> + * Usage in seq.h for details.
> + *
> + * ('where' is used in debug logging. Commonly one would use seq_wait() to
> + * automatically provide the caller's source file and line number for
> + * 'where'.) */
> void
> -seq_wait(const struct seq *seq_, uint64_t value)
> +seq_wait_at(const struct seq *seq_, uint64_t value, const char *where)
> OVS_EXCLUDED(seq_mutex)
> {
> struct seq *seq = CONST_CAST(struct seq *, seq_);
>
> ovs_mutex_lock(&seq_mutex);
> if (value == seq->value) {
> - seq_wait__(seq, value);
> + seq_wait__(seq, value, where);
> } else {
> - poll_immediate_wake();
> + poll_immediate_wake_at(where);
> }
> ovs_mutex_unlock(&seq_mutex);
> }
> diff --git a/lib/seq.h b/lib/seq.h
> index c764809..38c0e52 100644
> --- a/lib/seq.h
> +++ b/lib/seq.h
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (c) 2013 Nicira, Inc.
> + * Copyright (c) 2013, 2014 Nicira, Inc.
> *
> * Licensed under the Apache License, Version 2.0 (the "License");
> * you may not use this file except in compliance with the License.
> @@ -111,6 +111,7 @@
> */
>
> #include <stdint.h>
> +#include "util.h"
>
> /* For implementation of an object with a sequence number attached. */
> struct seq *seq_create(void);
> @@ -119,7 +120,9 @@ void seq_change(struct seq *);
>
> /* For observers. */
> uint64_t seq_read(const struct seq *);
> -void seq_wait(const struct seq *, uint64_t value);
> +
> +void seq_wait_at(const struct seq *, uint64_t value, const char *where);
> +#define seq_wait(seq, value) seq_wait_at(seq, value, SOURCE_LOCATOR)
>
> /* For poll_block() internal use. */
> void seq_woke(void);
> --
> 1.7.10.4
>
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