On Thu, Feb 17, 2000 at 09:18:59AM -0500, Todd Vierling wrote:
> On Wed, 16 Feb 2000, Allen Briggs wrote:
> 
> : > Anyway, I made it this far in getting Postgres to run:
> : > [...]
> : > FATAL: s_lock(20318030) at spin.c:114, stuck spinlock. Aborting.
> : 
> : That's as far as I got, too.  I haven't gotten back to it.  I
> : was suspecting LP64 bugs when I last looked at it.  Does anyone
> : know if it really runs on Tru64/OSF or Linux/alpha?
> 
> No, it does not.  Search AltaVista for "+alpha +linux +postgresql"--it's
> littered with LP64 breakage.

Well, I got farther. Can someone explain this to me? I can't figure out
why it breaks like this. I found that if I make tas() not be __inline__
then I can get Postgres to work well enough to build it's own
databases and then finish installing. (I'll have a set of patches
ready hopefully tonight -- perhaps Postgres won't be perfect but it'll
be closer.)

(make post-install 2>&1 log ; tail log)

(locklock = 1, flag = 0, nshlocks = 0, shlock = 0, exlock =0)
S_LOCK in: lock 540131376 *lock 0 file spin.c 117
S_LOCK progress: lock 540131376 *lock 1 file spin.c 117
s_lock entry: lock 4835098672, *lock 1, spin.c, 117
                   ^^^^^^^^^^ WRONG. Should be 540131376

Output generated starting with: (in void SpinAcquire(lockid))
        PRINT_LOCK(slckP);
        switch (slckP->flag)
        {
                case NOLOCK:
                        slckP->flag = EXCLUSIVELOCK;
                        S_LOCK(&(slckP->exlock));

Where S_LOCK is: (in include storage/s_lock.h)
extern void s_lock(volatile slock_t *lock, const char *file, const int line);
 
#define S_LOCK(lock) \
        do { \  
                fprintf(stderr,"S_LOCK in: lock %d *lock %d file %s %d\n", lock,
 *lock, __FILE__, __LINE__); \ 
                if (TAS((volatile slock_t *) lock)) { fprintf(stderr,"S_LOCK pro
gress: lock %d *lock %d file %s %d\n", lock, *lock, __FILE__, __LINE__);\
                        s_lock((volatile slock_t *) lock, __FILE__, __LINE__);}
\
                fprintf(stderr,"S_LOCK out: lock %d *lock %d file %s %d\n", lock
, *lock, __FILE__, __LINE__); \ 
        } while (0)

Next s_lock has:
        fprintf(stderr, "s_lock entry: lock %ld, *lock %d, %s, %d\n",
                         lock, *lock, file, line);

        while (TAS(lock))
        {
(snip) 

Last, TAS is:
#define TAS(lock) tas(lock)
#define S_UNLOCK(lock) { fprintf(stderr, "unlock %d %s %d\n", lock, __FILE__, __
LINE__ ); __asm__("mb"); *(lock) = 0; }

/* static __inline__ int */
static __inline__ int
tas(volatile slock_t *lock)
{  
        register slock_t _res;
 
__asm__("    ldq   $0, %0              \n\
                 bne   $0, 3f          \n\
                 ldq_l $0, %0              \n\
                 bne   $0, 3f          \n\
                 or    $31, 1, $0          \n\
                 stq_c $0, %0              \n\
                 beq   $0, 2f              \n\
                 bis   $31, $31, %1        \n\
                 mb                                \n\
                 jmp   $31, 4f             \n\
              2: or    $31, 1, $0              \n\
              3: bis   $0, $0, %1              \n\
              4: nop      ": "=m"(*lock), "=r"(_res): :"0");
  
        return (int) _res;
}


-- 
XCOMM Kevin P. Neal:  Senior, CSC, NCSU    http://www.pobox.com/~kpn/
XCOMM 
XCOMM "There are %d threatening little dwarves in the room with you."
XCOMM    -- BSD /usr/games/adventure source code.