[asterisk-bugs] [JIRA] (DAHLIN-329) Support multiple dynamic spans with FIFO

[Pavel Selivanov (JIRA)]

    [ https://issues.asterisk.org/jira/browse/DAHLIN-329?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=211570#comment-211570 ] 

Pavel Selivanov commented on DAHLIN-329:
----------------------------------------

In two words - I like you fixes like flood protection, tasklet in module_param.

What I don't like, and made it in another way:
I don't like a lot's of #if #else #endif, around all the code.
kfifo (FINALLY) finished changing their API.
That's great! I've wrapped it a bit.

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)
# define kfifo_in(fifo,buf,n) __kfifo_put(fifo,buf,n)
# define kfifo_in_spinlocked(fifo,buf,n,lock) kfifo_put(fifo,buf,n)
# define kfifo_out(fifo,buf,n) __kfifo_get(fifo,buf,n)
# define kfifo_out_spinlocked(fifo,buf,n,lock) kfifo_get(fifo,buf,n)
# define kfifo_size(fifo) (fifo->size)
# define my_kfifo_alloc(size,mask,lock) kfifo_alloc(size,mask,lock)
# define my_kfifo_free(fifo) kfifo_free(fifo)
#else // >= 2.6.35
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) /* 2.6.35 <= x < 2.6.36 */
#define kfifo_in_spinlocked(fifo, buf, n, lock) \
	kfifo_in_locked(fifo, buf, n, lock)
#define kfifo_out_spinlocked(fifo, buf, n, lock) \
	kfifo_out_locked(fifo, buf, n, lock)
#endif // < KERNEL_VERSION(2,6,36)
inline struct kfifo *my_kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock) {
        int ret;
	struct kfifo *fifo = kmalloc(sizeof(struct kfifo), gfp_mask);
	ret = kfifo_alloc (fifo, size, gfp_mask);
        return fifo;
}
inline void my_kfifo_free(struct kfifo *fifo) {
	kfifo_free (fifo);
	kfree (fifo);
}
#endif // < KERNEL_VERSION(2,6,35)

Now we can use ->timing field instead of DAHDI_FLAG_RUNNING to notify, we're online.

What is msgbuf2 for ? Not used.

kfifo_alloc have an alignment bug in kernels (still not fixed).
It will crash kernel on some channels number (like 128)...
sprintf should be changed to more up-to-date seq_printf.

I'll attach my current patches (to DAHDI 2.6.1).
I will upgdete it to DAHDI 2.7.0.1, and will attach them here.
It can take time, as I'll have a business trip on Sun.
I'll try to update untill Sun.

Thank you all.

                
> Support multiple dynamic spans with FIFO
> ----------------------------------------
>
>                 Key: DAHLIN-329
>                 URL: https://issues.asterisk.org/jira/browse/DAHLIN-329
>             Project: DAHDI-Linux
>          Issue Type: Improvement
>      Security Level: None
>          Components: dahdi (the module), dahdi_dynamic
>    Affects Versions: 2.7.0
>         Environment: Kernel versions 2.6.24, 2.6.38 and 3.2.0 tested
>            Reporter: Michael Walton
>            Assignee: Russ Meyerriecks
>         Attachments: dahdi-dynamic-multispan-fifo.patch
>
>
> The dynamic span driver works for one span, but is unable to handle the phase differences caused by line and network jitter and clock drift in a multiple span situation. The introduction of a configurable receive FIFO,  proper master clock priority switching and slip/skip processing solves this problem. Additionally, to support configurations where no telephony hardware is present, the highres timer from (defunct) dahdi_dummy is re-introduced into dahdi base to replace the core timer functionality (which is limited to 250Hz) with a true 1000Hz tick. As with the core timer, this is the fallback timing when no span provides master timing.
> Dynamic multispan introduces:
>  * Configurable fifo on incoming dynamic frames
>  * Master/slave dynamic spans with priority switching based on alarm status
>  * All transmit and receive processing is done in the dahdi_dynamic_run tasklet to ensure proper handling of jitter and phase differences
>  * Unreachable spans (RED alarm) switch to a poll mode to prevent network being flooded by 1ms frames that go nowhere
>  * Slip/skip statistics per span available on /proc/dahdi/dahdi_dynamic_stats
>  * High res timer added to dahdi-base to replace core timer with true 1ms tick timer
>  

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