[ovs-dev] [PATCH 1/2] lockfile: Occasionally log a warning when waiting for a lockfile.

Justin Pettit jpettit at nicira.com
Mon Mar 8 22:25:22 UTC 2010


Looks good.

--Justin


On Mar 8, 2010, at 2:02 PM, Ben Pfaff wrote:

> Waiting for a lockfile can cause mysterious pauses for users.  Logging a
> warning to the console every so often gives them feedback on what is
> happening.
> 
> Reported-by: Justin Pettit <jpettit at nicira.com>
> ---
> lib/lockfile.c |    8 +++++++-
> 1 files changed, 7 insertions(+), 1 deletions(-)
> 
> diff --git a/lib/lockfile.c b/lib/lockfile.c
> index 9bb7c6b..100440e 100644
> --- a/lib/lockfile.c
> +++ b/lib/lockfile.c
> @@ -1,4 +1,4 @@
> - /* Copyright (c) 2008, 2009 Nicira Networks
> + /* Copyright (c) 2008, 2009, 2010 Nicira Networks
>  *
>  * Licensed under the Apache License, Version 2.0 (the "License");
>  * you may not use this file except in compliance with the License.
> @@ -84,6 +84,7 @@ lockfile_lock(const char *file, int timeout, struct lockfile **lockfilep)
>      * because the Open vSwitch code that currently uses lock files does so in
>      * stylized ways such that any number of readers may access a file while it
>      * is being written. */
> +    long long int warn_elapsed = 1000;
>     long long int start, elapsed;
>     char *lock_name;
>     int error;
> @@ -98,6 +99,11 @@ lockfile_lock(const char *file, int timeout, struct lockfile **lockfilep)
>         error = lockfile_try_lock(lock_name, timeout > 0, lockfilep);
>         time_refresh();
>         elapsed = time_msec() - start;
> +        if (elapsed > warn_elapsed) {
> +            warn_elapsed *= 2;
> +            VLOG_WARN("%s: waiting for lock file, %lld ms elapsed",
> +                      lock_name, elapsed);
> +        }
>     } while (error == EINTR && (timeout == INT_MAX || elapsed < timeout));
> 
>     if (!error) {
> -- 
> 1.6.6.1
> 
> 
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