Line data    Source code

       1             : #ifndef HEADER_fd_src_disco_wait_info_fd_wait_info_h
       2             : #define HEADER_fd_src_disco_wait_info_fd_wait_info_h
       3             : 
       4             : /* fd_wait_info provides a shared topology object that holds the data
       5             :    the `wait` command needs to determine a safe restart window.
       6             : 
       7             :    Expects a single producer and one or more consumers.  Readers never
       8             :    block: they retry against a sequence (seq) counter the writer
       9             :    increments before and after each update.
      10             : 
      11             :    The sequence uses FD_VOLATILE + FD_COMPILER_MFENCE rather than C11
      12             :    atomics.  This is sufficient on x86-64 (TSO): stores are globally
      13             :    visible in program order, so compiler fences alone provide the
      14             :    acquire/release semantics the sequence requires.  Single producer
      15             :    means no CAS is needed on the write side. */
      16             : 
      17             : #include "../../util/log/fd_log.h"
      18             : 
      19           0 : #define FD_WAIT_INFO_MAGIC (0xf17eda2c57490000UL) /* firedancer wait_info (wi) ver 0 */
      20             : 
      21             : struct fd_wait_info {
      22             :   /* Health */
      23             :   int   caught_up;
      24             : 
      25             :   /* Leader gap */
      26             :   ulong reset_slot;
      27             :   ulong tip_slot;              /* highest slot seen from the cluster, 0 if unknown */
      28             :   ulong leader_highwater_slot; /* highest slot led, 0 if none */
      29             :   int   next_leader_known;     /* 0: leader schedule unavailable */
      30             :   ulong next_leader_slot;      /* 0: no upcoming leader slots */
      31             :   ulong leader_slot;           /* non-zero when actively leading */
      32             :   ulong epoch_end_slot;
      33             :   ulong slots_per_epoch;
      34             :   ulong ns_per_slot;
      35             : 
      36             :   /* Delinquent stake.  Tower derives it from vote account
      37             :      last_vote_slot; Alpenglow from the block footer reward certs.
      38             :      0 until the first real figure is computed. */
      39             :   int   delinquent_known;
      40             :   ulong delinquent_stake_lamports;
      41             :   ulong cluster_active_stake_lamports;
      42             : 
      43             :   /* Snapshot status */
      44             :   int   snap_active;  /* 1 while snapmk tile is writing */
      45             :   ulong snap_finished_full;
      46             :   ulong snap_finished_incr;
      47             :   ulong snap_full_interval_blocks; /* 0: periodic fulls disabled */
      48             :   ulong snap_incr_interval_blocks; /* 0: periodic incrementals disabled */
      49             :   ulong snap_produced_incr_cnt;    /* incrementals produced, never found */
      50             : };
      51             : 
      52             : typedef struct fd_wait_info fd_wait_info_t;
      53             : 
      54             : struct fd_wait_info_box {
      55             :   ulong magic;  /* ==FD_WAIT_INFO_MAGIC */
      56             :   ulong seq;    /* lsb==1 implies active write */
      57             :   fd_wait_info_t info;
      58             : };
      59             : 
      60             : typedef struct fd_wait_info_box fd_wait_info_box_t;
      61             : 
      62             : FD_PROTOTYPES_BEGIN
      63             : 
      64             : static inline void *
      65           0 : fd_wait_info_box_new( void * shmem ) {
      66           0 :   fd_wait_info_box_t * wi = (fd_wait_info_box_t *)shmem;
      67           0 :   if( FD_UNLIKELY( !wi ) ) {
      68           0 :     FD_LOG_WARNING(( "NULL shmem" ));
      69           0 :     return NULL;
      70           0 :   }
      71           0 :   fd_memset( wi, 0, sizeof(fd_wait_info_box_t) );
      72           0 :   FD_VOLATILE( wi->magic ) = FD_WAIT_INFO_MAGIC;
      73           0 :   return (void *)wi;
      74           0 : }
      75             : 
      76             : static inline fd_wait_info_box_t *
      77           0 : fd_wait_info_box_join( void * shwi ) {
      78           0 :   if( FD_UNLIKELY( !shwi ) ) {
      79           0 :     FD_LOG_WARNING(( "NULL shwi" ));
      80           0 :     return NULL;
      81           0 :   }
      82           0 :   fd_wait_info_box_t * wi = (fd_wait_info_box_t *)shwi;
      83           0 :   if( FD_UNLIKELY( wi->magic!=FD_WAIT_INFO_MAGIC ) ) {
      84           0 :     FD_LOG_WARNING(( "bad magic" ));
      85           0 :     return NULL;
      86           0 :   }
      87           0 :   return wi;
      88           0 : }
      89             : 
      90             : /* fd_wait_info_seq reads the sequence counter. */
      91             : 
      92             : static inline ulong
      93           0 : fd_wait_info_seq( fd_wait_info_box_t const * src ) {
      94           0 :   FD_COMPILER_MFENCE();
      95           0 :   ulong seq = FD_VOLATILE_CONST( src->seq );
      96           0 :   FD_COMPILER_MFENCE();
      97           0 :   return seq;
      98           0 : }
      99             : 
     100             : /* fd_wait_info_try_read attempts a single consistent read.
     101             :    Returns dst on success, NULL if a write was in progress. */
     102             : 
     103             : static inline fd_wait_info_t *
     104             : fd_wait_info_try_read( fd_wait_info_t *           dst,
     105           0 :                        fd_wait_info_box_t const * src ) {
     106           0 :   ulong seq0 = fd_wait_info_seq( src );
     107           0 :   if( FD_UNLIKELY( seq0 & 1UL ) ) return NULL;
     108           0 :   memcpy( dst, &src->info, sizeof(fd_wait_info_t) );
     109           0 :   ulong seq1 = fd_wait_info_seq( src );
     110           0 :   if( FD_LIKELY( seq0==seq1 ) ) return dst;
     111           0 :   return NULL;
     112           0 : }
     113             : 
     114             : static inline void
     115           0 : fd_wait_info_write_begin( fd_wait_info_box_t * dst ) {
     116           0 :   FD_COMPILER_MFENCE();
     117           0 :   FD_VOLATILE( dst->seq ) = dst->seq + 1UL;
     118           0 :   FD_COMPILER_MFENCE();
     119           0 : }
     120             : 
     121             : static inline void
     122           0 : fd_wait_info_write_end( fd_wait_info_box_t * dst ) {
     123           0 :   FD_COMPILER_MFENCE();
     124           0 :   FD_VOLATILE( dst->seq ) = dst->seq + 1UL;
     125           0 :   FD_COMPILER_MFENCE();
     126           0 : }
     127             : 
     128             : FD_PROTOTYPES_END
     129             : 
     130             : #endif /* HEADER_fd_src_disco_wait_info_fd_wait_info_h */