Re: [ANNOUNCE] high-res-timers patches for 2.6.6

[Stephen Hemminger]

A couple of comments on posix-hrt-core-04.06.09.patch

1. Comment in hrtime.h is out of date, you are using seq_lock to do the read
   stuff now, an example is...

+ * Global locking issues: 
+ *
+ *      Time is locked with the xtime_lock using read/write locks.
+ *      Note: It is assumed that the do_timer() call is  protected by
+ *      write_lock(&xtime_lock).
+ *
+ *      Using code must not change, but only read, the protected
+ *      variables (xtime, jiffies, any temps tha need protection in the
+ *      arch_get_cycles() code).  Usage is as follows:
+ *
+ *      read_lock_irq(&xtime_lock);
+ *          do the reads
+ *      read_unlock_irq(&xtime)


2. Don't like new definition of running_timer; use explicit memory barriers
   not volatile please.

struct tvec_t_base_s {
 	spinlock_t lock;
 	unsigned long timer_jiffies;
-	struct timer_list *running_timer;
-	tvec_root_t tv1;
-	tvec_t tv2;
-	tvec_t tv3;
-	tvec_t tv4;
-	tvec_t tv5;
+ 	volatile struct timer_list * volatile running_timer;
+ 	struct list_head tv[NEW_TVEC_SIZE]line_aligned_in_smp;

3. The IF_HIGH_RES() macro looks cute, but get confusing, and makes the code
   less readable.
-
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