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SubjectRe: [RFC/PATCH] 2.6.24-rcx: Make sys_poll() wait at least timeout ms
Karsten Wiese wrote:
> Hi,
>
> while playing with jackd on 2.6.24-rcx, I found poll() timing out too early.
> That is: earlier than its timeout argument specified.
> Setting poll()'s timeout argument to "required timeout" + "1 jiffy in ms"
> fixed it. Patch below should fix it too. Correct?
> Untested.
> Otherwise 2.6.24-rc5 ticks just fine here, thanks.
>
> Karsten
>
> ------------->
> Make sys_poll() wait at least timeout ms
>
> schedule_timeout(jiffies) waits for at least jiffies - 1.
> Add 1 jiffie to the timeout_jiffies calculated in sys_poll() to wait at least
> timeout_msecs, like poll() manpage says.
>
> Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
> ---
> fs/select.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/select.c b/fs/select.c
> index 47f4792..5633fe9 100644
> --- a/fs/select.c
> +++ b/fs/select.c
> @@ -739,7 +739,7 @@ asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
> timeout_jiffies = -1;
> else
> #endif
> - timeout_jiffies = msecs_to_jiffies(timeout_msecs);
> + timeout_jiffies = msecs_to_jiffies(timeout_msecs) + 1;
> } else {
> /* Infinite (< 0) or no (0) timeout */
> timeout_jiffies = timeout_msecs;

That seems fishy. What is your value of HZ and what is the timeout value
that was passed in the bad case?

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/



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