LCOV - code coverage report
Current view: top level - util/tmpl - fd_pool_para.c (source / functions) Hit Total Coverage
Test: cov.lcov Lines: 275 300 91.7 %
Date: 2025-01-08 12:08:44 Functions: 46 68 67.6 %

          Line data    Source code
       1             : /* Generate prototypes, inlines and/or implementations for concurrent
       2             :    persistent shared element pools.  A pool can hold a practically
       3             :    unbounded number of elements.  Acquiring an element from and
       4             :    releasing an element to a pool are typically fast O(1) time.
       5             :    Requires small O(1) space per element.
       6             : 
       7             :    The current implementation is based on a lockfree stack.  Acquire and
       8             :    release are done via atomic compare-and-swap of the stack top.  As
       9             :    such, concurrent usage requires FD_HAS_ATOMIC support (this can still
      10             :    be used on platforms without FD_HAS_ATOMIC but it will not be safe
      11             :    for concurrent usage).  Stack top versioning is used to handle ABA.
      12             :    Versioning has been been tweaked to support locked pool operations
      13             :    like initialization (and thus this can also be used without changes
      14             :    as a more conventional spin lock based concurrent stack).
      15             :    Unsurprisingly, the current implementation is equally usable as a
      16             :    concurrent element stack (though the implementation may be changed in
      17             :    the future to better support ultra high contention ultra high
      18             :    concurrency ala fd_alloc).
      19             : 
      20             :    The current implementation is optimized for pools with a moderate
      21             :    number of reasonably localized users (e.g. a handful of cores and
      22             :    memory on the same NUMA node).  Various operations are slightly more
      23             :    optimal when the size of a pool element is an integer power of 2.
      24             :    Operations do much internal integrity checking / bounds checking for
      25             :    use in high reliability / high security environments.
      26             : 
      27             :    This API is designed for tight and flexible composition with treaps,
      28             :    heaps, lists, maps, etc.  Further, a pool can be persisted beyond the
      29             :    lifetime of the creating process, be used inter-process, be relocated
      30             :    in memory, be naively serialized/deserialized, be moved between
      31             :    hosts, use index compression for cache and memory bandwidth
      32             :    efficiency, etc.
      33             : 
      34             :    Typical usage:
      35             : 
      36             :      struct myele {
      37             :        ulong next; // Technically "POOL_IDX_T POOL_NEXT" (default is ulong next), managed by the mypool when in the mypool
      38             : 
      39             :        ... next can be located arbitrarily in the element and can be
      40             :        ... reused for other purposes when the element is not in a
      41             :        ... mypool.  elements are all located in a linear array element
      42             :        ... store whose lifetime is at least that of the mypool.
      43             : 
      44             :      };
      45             : 
      46             :      typedef struct myele myele_t;
      47             : 
      48             :      #define POOL_NAME  mypool
      49             :      #define POOL_ELE_T myele_t
      50             :      #include "tmpl/fd_pool_para.c"
      51             : 
      52             :    will declare the following APIs as a header only style library in the
      53             :    compilation unit:
      54             : 
      55             :      // A mypool_t is a stack declaration friendly quasi-opaque handle
      56             :      // used to describe a join to a mypool.  E.g. it is fine to do
      57             :      // "mypool_t join[1];" to allocate a mypool_t but the contents
      58             :      // should be used directly.
      59             : 
      60             :      typedef struct mypool_private mypool_t;
      61             : 
      62             :      // Constructors
      63             : 
      64             :      // mypool_ele_max_max returns the maximum element store capacity
      65             :      // compatible with a mypool.
      66             : 
      67             :      ulong mypool_ele_max_max( void );
      68             : 
      69             :      // mypool_{align,footprint} returns the alignment and footprint
      70             :      // needed for a memory region to be used as a mypool.  align will
      71             :      // be an integer power-of-two and footprint will be a multiple of
      72             :      // align.
      73             :      //
      74             :      // mypool_new formats a memory region with the appropriate
      75             :      // alignment and footprint into a mypool.  shmem points in the the
      76             :      // caller's address space of the memory region to format.  Returns
      77             :      // shmem on success (mypool has ownership of the memory region) and
      78             :      // NULL on failure (no changes, logs details).  Caller is not
      79             :      // joined on return.  The mypool will be empty and unlocked.
      80             :      //
      81             :      // mypool_join joins a mypool.  ljoin points to a mypool_t
      82             :      // compatible memory region in the caller's address space used to
      83             :      // hold info about the local join, shpool points in the caller's
      84             :      // address space to the memory region containing the mypool, shele
      85             :      // points in the caller's address space to mypool's element store,
      86             :      // and ele_max is the element store's capacity.  Returns a handle
      87             :      // to the caller's local join on success (join has ownership of the
      88             :      // ljoin region) and NULL on failure (no changes, logs details).
      89             :      //
      90             :      // mypool_leave leaves a mypool.  join points to a current local
      91             :      // join.  Returns the memory used for the local join (caller has
      92             :      // ownership on return and caller is no longer joined) on success
      93             :      // and NULL on failure (no changes, logs details).  Use the join
      94             :      // accessors before leaving to get shpool, shele and ele_max used
      95             :      // by the join if needed.
      96             :      //
      97             :      // mypool_delete unformats a memory region used as a mypool.
      98             :      // Assumes shpool points in the caller's address space to the
      99             :      // memory region containing the mypool and that there are no
     100             :      // current joins globally.  Returns shpool on success (caller has
     101             :      // ownership of the memory region and any elements still in the
     102             :      // mypool are acquired by the caller) and NULL on failure (no
     103             :      // changes, logs details).
     104             : 
     105             :      ulong      mypool_align    ( void );
     106             :      ulong      mypool_footprint( void );
     107             :      void *     mypool_new      ( void *     shmem );
     108             :      mypool_t * mypool_join     ( void *     ljoin, void * shpool, void * shele, ulong ele_max );
     109             :      void *     mypool_leave    ( mypool_t * join );
     110             :      void *     mypool_delete   ( void *     shpool );
     111             : 
     112             :      // mypool_{shpool,shele,ele_max} return join details.  Assumes join
     113             :      // is a current local join.  mypool_{shpool_const,shele_const} are
     114             :      // const correct versions.  The lifetime of the returned pointers
     115             :      // is the lifetime of the join.
     116             : 
     117             :      void const * mypool_shpool_const( mypool_t const * join );
     118             :      void const * mypool_shele_const ( mypool_t const * join );
     119             :      ulong        mypool_ele_max     ( mypool_t const * join );
     120             : 
     121             :      void * mypool_shpool( mypool_t * join );
     122             :      void * mypool_shele ( mypool_t * join );
     123             : 
     124             :      // mypool_idx_null returns the element store index used to
     125             :      // represent null for a mypool.
     126             :      //
     127             :      // mypool_idx_is_null returns 1 if an element store index is the
     128             :      // null index value and 0 otherwise.
     129             :      //
     130             :      // mypool_idx returns the element store index for the element
     131             :      // pointed to by ele in the caller's address space.  Assumes join
     132             :      // is a current local join.  If ele is NULL or not into the element
     133             :      // store, returns the element store null index.
     134             :      //
     135             :      // mypool_ele returns a pointer in the caller's address space to
     136             :      // the element whose element store index is ele_idx.  If ele_idx is
     137             :      // the null value or invalid, returns NULL.  mypool_ele_const is a
     138             :      // const correct version.
     139             :      //
     140             :      // These are usually not needed but allow translating pointers to
     141             :      // element store elements from one address space to another.
     142             : 
     143             :      ulong mypool_idx_null   ( void );
     144             :      int   mypool_idx_is_null( ulong idx );
     145             :      ulong mypool_idx        ( mypool_t const * join, myele_t const * ele );
     146             : 
     147             :      myele_t const * mypool_ele_const( mypool_t const * join, ulong ele_idx );
     148             :      myele_t *       mypool_ele      ( mypool_t *       join, ulong ele_idx );
     149             : 
     150             :      // mypool_peek returns a pointer in the local address space to the
     151             :      // next element to acquire from the mypool or NULL if the mypool
     152             :      // was empty at some point during the call.  mypool_peek_const is a
     153             :      // const correct version.  Because of concurrent operations, unless
     154             :      // the caller is holding a lock on the mypool, this may not be the
     155             :      // actual element the caller will acquire next from the mypool.
     156             : 
     157             :      myele_t const * mypool_peek_const( mypool_t const * join );
     158             :      myele_t *       mypool_peek      ( mypool_t       * join );
     159             : 
     160             :      // mypool_acquire acquires an element from a mypool.  Assumes join
     161             :      // is a current local join.  If the mypool is empty or an error
     162             :      // occurs, returns sentinel (arbitrary).  A non-zero / zero value
     163             :      // for blocking indicates locked operations on the mypool are / are
     164             :      // not allowed to block the caller.  If opt_err is not NULL, on
     165             :      // return, *_opt_err will indicate FD_POOL_SUCCESS (zero) or a
     166             :      // FD_POOL_ERR code (negative).  On success, the returned value
     167             :      // will be a pointer in the caller's address space to the element
     168             :      // store element acquired from the mypool.  On failure for any
     169             :      // reason, the value returned will be sentinel and the mypool will
     170             :      // be unchanged.  Reasons for failure:
     171             :      //
     172             :      // FD_POOL_ERR_EMPTY: the mypool contained no elements at some
     173             :      // point during the call.
     174             :      //
     175             :      // FD_POOL_ERR_AGAIN: the mypool was locked at some point during
     176             :      // the call.  Never returned for a blocking call (but then locking
     177             :      // operations can then potentially block the caller indefinitely).
     178             :      //
     179             :      // FD_POOL_ERR_CORRUPT: memory corruption was detected during the
     180             :      // call.
     181             : 
     182             :      myele_t * mypool_acquire( mypool_t * join, myele_t * sentinel, int blocking, int * _opt_err );
     183             : 
     184             :      // mypool_release releases an element to a mypoool.  Assumes join
     185             :      // is a current local join, ele is a pointer in the caller's
     186             :      // address space to the element, and the element is currently not
     187             :      // in the mypool.  Returns FD_POOL_SUCCESS (zero) on success (the
     188             :      // element will be in the mypool on return) and a FD_POOL_ERR code
     189             :      // (negative) on failure (the element will not be in the mypool on
     190             :      // return).  Reasons for failure:
     191             :      //
     192             :      // FD_POOL_ERR_INVAL: ele does not point to an element in mypool's
     193             :      // element store.
     194             :      //
     195             :      // FD_POOL_ERR_AGAIN: the mypool was locked at some point during
     196             :      // the call.  Never returned for a blocking call (but locking
     197             :      // operations can then potentially block the caller indefinitely).
     198             :      //
     199             :      // FD_POOL_ERR_CORRUPT: memory corruption was detected during the
     200             :      // call.
     201             : 
     202             :      int mypool_release( mypool_t * join, myele_t * ele, int blocking );
     203             : 
     204             :      // mypool_is_locked returns whether or not a mypool is locked.
     205             :      // Assumes join is a current local join.
     206             : 
     207             :      int mypool_is_locked( mypool_t const * join );
     208             : 
     209             :      // mypool_lock will lock a mypool (e.g. pausing concurrent acquire
     210             :      // / release operations).  A non-zero / zero value for blocking
     211             :      // indicates the call should / should not wait to lock the mypool
     212             :      // if it is currently locked.  Returns FD_POOL_SUCCESS on success
     213             :      // (caller has the lock on return) and FD_POOL_ERR_AGAIN on failure
     214             :      // (pool was already locked at some point during the call).  AGAIN
     215             :      // is never returned if blocking is requested.  Assumes join is a
     216             :      // current local join.
     217             : 
     218             :      int mypool_lock( mypool_t * join, int blocking );
     219             : 
     220             :      // mypool_unlock will unlock a mypool (e.g. resuming concurrent
     221             :      // acquire / release operations).  Assumes join is a current local
     222             :      // join and the caller has a lock on mypool.  Guaranteed to
     223             :      // succeed.
     224             : 
     225             :      void mypool_unlock( mypool_t * join );
     226             : 
     227             :      // mypool_reset resets the mypool.  On return, it will hold all but
     228             :      // the leading sentinel_cnt elements in the element store (e.g.
     229             :      // initialization after creation) in ascending order.  If
     230             :      // sentinel_cnt is greater than or equal to the element store
     231             :      // capacity, the mypool will be empty on return.  Thus, on return,
     232             :      // if sentinel_cnt is zero, every element in the element store will
     233             :      // be in the mypool and, if sentinel_cnt is ele_max or greater
     234             :      // (e.g. ULONG_MAX), every element will be removed from the mypool.
     235             :      // Assumes join is a current local join and the mypool is locked or
     236             :      // otherwise idle.
     237             : 
     238             :      void mypool_reset( mypool_t * join, ulong sentinel_cnt );
     239             : 
     240             :      // mypool_verify returns FD_POOL_SUCCESS if join appears to be
     241             :      // current local join to a valid mypool and FD_POOL_ERR_CORRUPT
     242             :      // otherwise (logs details).  Assumes join is a current local join
     243             :      // and the mypool is locked or otherwise idle.
     244             : 
     245             :      int mypool_verify( mypool_t const * join );
     246             : 
     247             :      // mypool_strerror converts an FD_POOL_SUCCESS / FD_POOL_ERR code
     248             :      // into a human readable cstr.  The lifetime of the returned
     249             :      // pointer is infinite.  The returned pointer is always to a
     250             :      // non-NULL cstr.
     251             : 
     252             :      char const * mypool_strerror( int err );
     253             : 
     254             :    Do this as often as desired in a compilation unit to get different
     255             :    types of concurrent pools.  Options exist for generating library
     256             :    header prototypes and/or library implementations for concurrent pools
     257             :    usable across multiple compilation units.  Additional options exist
     258             :    to use index compression, configuring versioning, etc. */
     259             : 
     260             : /* POOL_NAME gives the API prefix to use for pool */
     261             : 
     262             : #ifndef POOL_NAME
     263             : #error "Define POOL_NAME"
     264             : #endif
     265             : 
     266             : /* POOL_ELE_T is the pool element type. */
     267             : 
     268             : #ifndef POOL_ELE_T
     269             : #error "Define POOL_ELE_T"
     270             : #endif
     271             : 
     272             : /* POOL_IDX_T is the type used for the next field in the POOL_ELE_T.
     273             :    Should be a primitive unsigned integer type.  Defaults to ulong.  A
     274             :    pool can't use element stores with a capacity that can't be
     275             :    represented by a POOL_IDX_T.  (E.g. if ushort, the maximum capacity
     276             :    pool compatible element store is 65535 elements.) */
     277             : 
     278             : #ifndef POOL_IDX_T
     279             : #define POOL_IDX_T ulong
     280             : #endif
     281             : 
     282             : /* POOL_NEXT is the POOL_ELE_T next field */
     283             : 
     284             : #ifndef POOL_NEXT
     285             : #define POOL_NEXT next
     286             : #endif
     287             : 
     288             : /* POOL_ALIGN gives the alignment required for the pool shared memory.
     289             :    Default is 128 for double cache line alignment.  Should be at least
     290             :    ulong alignment. */
     291             : 
     292             : #ifndef POOL_ALIGN
     293             : #define POOL_ALIGN (128UL)
     294             : #endif
     295             : 
     296             : /* POOL_IDX_WIDTH gives the number of bits in a ulong to reserve for
     297             :    encoding the element store index in a versioned index.  Element store
     298             :    capacity should be representable in this width.  Default is 43 bits
     299             :    (e.g. enough to support a ~1 PiB element store of 128 byte elements).
     300             :    The versioning width will be 64-POOL_IDX_WIDTH.  Since the least
     301             :    significant bit of the version is used to indicate global locking,
     302             :    versioning width should be at least 2 and ideally as large as
     303             :    possible.  With the 43 default, version numbers will not be reused
     304             :    until 2^20 individual operations have been done. */
     305             : 
     306             : #ifndef POOL_IDX_WIDTH
     307    29295030 : #define POOL_IDX_WIDTH (43)
     308             : #endif
     309             : 
     310             : /* POOL_MAGIC is the magic number to use for the structure to aid in
     311             :    persistent and or IPC usage. */
     312             : 
     313             : #ifndef POOL_MAGIC
     314           6 : #define POOL_MAGIC (0xf17eda2c37c90010UL) /* firedancer cpool version 0 */
     315             : #endif
     316             : 
     317             : /* POOL_IMPL_STYLE controls what to generate:
     318             :      0 - local use only
     319             :      1 - library header declaration
     320             :      2 - library implementation */
     321             : 
     322             : #ifndef POOL_IMPL_STYLE
     323             : #define POOL_IMPL_STYLE 0
     324             : #endif
     325             : 
     326             : /* Commom pool error codes (FIXME: probably should get around to making
     327             :    unified error codes and string handling across all util at least so
     328             :    we don't have to do this in the generator itself) */
     329             : 
     330     7324662 : #define FD_POOL_SUCCESS     ( 0)
     331         780 : #define FD_POOL_ERR_INVAL   (-1)
     332        3675 : #define FD_POOL_ERR_AGAIN   (-2)
     333           3 : #define FD_POOL_ERR_CORRUPT (-3)
     334        3672 : #define FD_POOL_ERR_EMPTY   (-4)
     335             : //#define FD_POOL_ERR_FULL    (-5)
     336             : //#define FD_POOL_ERR_KEY     (-6)
     337             : 
     338             : /* Implementation *****************************************************/
     339             : 
     340    14649366 : #define POOL_VER_WIDTH (64-POOL_IDX_WIDTH)
     341             : 
     342             : #if POOL_IMPL_STYLE==0 /* local use only */
     343             : #define POOL_STATIC FD_FN_UNUSED static
     344             : #else /* library header and/or implementation */
     345             : #define POOL_STATIC
     346             : #endif
     347             : 
     348    40292013 : #define POOL_(n) FD_EXPAND_THEN_CONCAT3(POOL_NAME,_,n)
     349             : 
     350             : #if POOL_IMPL_STYLE!=2 /* need header */
     351             : 
     352             : #include "../bits/fd_bits.h"
     353             : 
     354             : struct __attribute__((aligned(POOL_ALIGN))) POOL_(shmem_private) {
     355             : 
     356             :   /* Note: there is no free count because that that isn't precisely
     357             :      knowable in a portable concurrent data structure.  (Not enough bits
     358             :      to squeeze into ver_top for large pools, requiring 128-bit wide
     359             :      ver_top would limit supported targets, etc). */
     360             : 
     361             :   ulong magic;   /* == POOL_MAGIC */
     362             :   ulong ver_top; /* Versioned index of the free stack top, top is in [0,ele_max) (not-empty) or is idx_null (empty) */
     363             : };
     364             : 
     365             : typedef struct POOL_(shmem_private) POOL_(shmem_t);
     366             : 
     367             : struct POOL_(private) {
     368             :   POOL_(shmem_t) * pool;    /* Pool location in the local address space */
     369             :   POOL_ELE_T *     ele;     /* Element store location in the local address space, NULL okay if ele_max==0 */
     370             :   ulong            ele_max; /* Element store capacity, in [0,ele_max_max] */
     371             : };
     372             : 
     373             : typedef struct POOL_(private) POOL_(t);
     374             : 
     375             : FD_PROTOTYPES_BEGIN
     376             : 
     377             : /* pool_private_vidx pack ver and idx into a versioned idx.  ver is
     378             :    masked to fit into POOL_VER_WIDTH bits.  idx is assumed in
     379             :    [0,ele_max_max].
     380             : 
     381             :    pool_private_vidx_{ver,idx} extract the {version,index} from a
     382             :    versioned index and will fit into {POOL_VER_WIDTH,POOL_IDX_WIDTH}
     383             :    bits. */
     384             : 
     385     7320993 : FD_FN_CONST static inline ulong POOL_(private_vidx)( ulong ver, ulong idx ) { return (ver<<POOL_IDX_WIDTH) | idx; }
     386             : 
     387     7324665 : FD_FN_CONST static inline ulong POOL_(private_vidx_ver)( ulong ver_idx ) { return ver_idx >> POOL_IDX_WIDTH;  }
     388     7324683 : FD_FN_CONST static inline ulong POOL_(private_vidx_idx)( ulong ver_idx ) { return (ver_idx << POOL_VER_WIDTH) >> POOL_VER_WIDTH; }
     389             : 
     390             : /* pool_private_{cidx,idx} compress/decompress a 64-bit in-register
     391             :    index to/from its in-memory representation. */
     392             : 
     393     3669699 : FD_FN_CONST static inline POOL_IDX_T POOL_(private_cidx)( ulong  idx ) { return (POOL_IDX_T) idx; }
     394     3663555 : FD_FN_CONST static inline ulong      POOL_(private_idx) ( ulong cidx ) { return (ulong)     cidx; }
     395             : 
     396             : /* pool_private_cas does a ulong FD_ATOMIC_CAS when FD_HAS_ATOMIC
     397             :    support is available and emulates it when not.  Similarly for
     398             :    pool_private_fetch_and_or.  When emulated, the pool will not be safe
     399             :    to use concurrently (but will still work). */
     400             : 
     401             : static inline ulong
     402             : POOL_(private_cas)( ulong volatile * p,
     403             :                     ulong            c,
     404     7320972 :                     ulong            s ) {
     405     7320972 :   ulong o;
     406     7320972 :   FD_COMPILER_MFENCE();
     407     7320972 : # if FD_HAS_ATOMIC
     408     7320972 :   o = FD_ATOMIC_CAS( p, c, s );
     409             : # else
     410             :   o = *p;
     411             :   *p = fd_ulong_if( o==c, s, c );
     412             : # endif
     413     7320972 :   FD_COMPILER_MFENCE();
     414     7320972 :   return o;
     415     7320972 : }
     416             : 
     417             : static inline ulong
     418             : POOL_(private_fetch_and_or)( ulong volatile * p,
     419           3 :                              ulong            b ) {
     420           3 :   ulong x;
     421           3 :   FD_COMPILER_MFENCE();
     422           3 : # if FD_HAS_ATOMIC
     423           3 :   x = FD_ATOMIC_FETCH_AND_OR( p, b );
     424             : # else
     425             :   x = *p;
     426             :   *p = x | b;
     427             : # endif
     428           3 :   FD_COMPILER_MFENCE();
     429           3 :   return x;
     430           3 : }
     431             : 
     432           0 : FD_FN_CONST static inline ulong POOL_(ele_max_max)( void ) { return (ulong)(POOL_IDX_T)(ULONG_MAX >> POOL_VER_WIDTH); }
     433             : 
     434           0 : FD_FN_CONST static inline ulong POOL_(align)    ( void ) { return alignof(POOL_(shmem_t)); }
     435           0 : FD_FN_CONST static inline ulong POOL_(footprint)( void ) { return sizeof (POOL_(shmem_t)); }
     436             : 
     437           3 : FD_FN_PURE  static inline void const * POOL_(shpool_const)( POOL_(t) const * join ) { return join->pool;    }
     438           3 : FD_FN_PURE  static inline void const * POOL_(shele_const) ( POOL_(t) const * join ) { return join->ele;     }
     439           3 : FD_FN_PURE  static inline ulong        POOL_(ele_max)     ( POOL_(t) const * join ) { return join->ele_max; }
     440             : 
     441           3 : FD_FN_PURE  static inline void * POOL_(shpool)( POOL_(t) * join ) { return join->pool; }
     442           6 : FD_FN_PURE  static inline void * POOL_(shele) ( POOL_(t) * join ) { return join->ele;  }
     443             : 
     444           0 : FD_FN_CONST static inline ulong POOL_(idx_null)( void ) { return (ulong)(POOL_IDX_T)(ULONG_MAX >> POOL_VER_WIDTH); }
     445    10988217 : FD_FN_CONST static inline int   POOL_(idx_is_null)( ulong idx ) { return idx==POOL_(idx_null)(); }
     446             : 
     447             : FD_FN_PURE static inline ulong
     448             : POOL_(idx)( POOL_(t)   const * join,
     449    18067218 :             POOL_ELE_T const * ele ) {
     450    18067218 :   ulong  ele_idx = (ulong)(ele - join->ele);
     451    18067218 :   return ele_idx<join->ele_max ? ele_idx : POOL_(idx_null)();
     452    18067218 : }
     453             : 
     454             : FD_FN_PURE static inline POOL_ELE_T const *
     455             : POOL_(ele_const)( POOL_(t) const * join,
     456        3078 :                   ulong            ele_idx ) {
     457        3078 :   POOL_ELE_T const * ele = join->ele;
     458        3078 :   return (ele_idx < join->ele_max) ? (ele + ele_idx) : NULL;
     459        3078 : }
     460             : 
     461             : FD_FN_PURE static inline POOL_ELE_T *
     462             : POOL_(ele)( POOL_(t) * join,
     463        3078 :             ulong      ele_idx ) {
     464        3078 :   POOL_ELE_T * ele = join->ele;
     465        3078 :   return (ele_idx < join->ele_max) ? (ele + ele_idx) : NULL;
     466        3078 : }
     467             : 
     468             : static inline POOL_ELE_T const *
     469          30 : POOL_(peek_const)( POOL_(t) const * join ) {
     470          30 :   POOL_(shmem_t) const * pool    = join->pool;
     471          30 :   POOL_ELE_T     const * ele     = join->ele;
     472          30 :   ulong                  ele_max = join->ele_max;
     473          30 :   FD_COMPILER_MFENCE();
     474          30 :   ulong ver_top = pool->ver_top;
     475          30 :   FD_COMPILER_MFENCE();
     476          30 :   ulong ele_idx = POOL_(private_vidx_idx)( ver_top );
     477          30 :   return (ele_idx<ele_max) ? ele + ele_idx : NULL;
     478          30 : }
     479             : 
     480          15 : static inline POOL_ELE_T * POOL_(peek)( POOL_(t) * join ) { return (POOL_ELE_T *)POOL_(peek_const)( join ); }
     481             : 
     482             : static inline int
     483           9 : POOL_(is_locked)( POOL_(t) const * join ) {
     484           9 :   POOL_(shmem_t) const * pool = join->pool;
     485           9 :   FD_COMPILER_MFENCE();
     486           9 :   ulong ver_top = pool->ver_top;
     487           9 :   FD_COMPILER_MFENCE();
     488           9 :   return (int)(POOL_(private_vidx_ver)( ver_top ) & 1UL);
     489           9 : }
     490             : 
     491             : static inline void
     492           3 : POOL_(unlock)( POOL_(t) * join ) {
     493           3 :   POOL_(shmem_t) * pool = join->pool;
     494           3 :   FD_COMPILER_MFENCE();
     495           3 :   pool->ver_top += 1UL<<POOL_IDX_WIDTH;
     496           3 :   FD_COMPILER_MFENCE();
     497           3 : }
     498             : 
     499             : POOL_STATIC void *     POOL_(new)   ( void *     shmem );
     500             : POOL_STATIC POOL_(t) * POOL_(join)  ( void *     ljoin, void * shpool, void * shele, ulong  ele_max );
     501             : POOL_STATIC void *     POOL_(leave) ( POOL_(t) * join );
     502             : POOL_STATIC void *     POOL_(delete)( void *     shpool );
     503             : 
     504             : POOL_STATIC POOL_ELE_T * POOL_(acquire)( POOL_(t) * join, POOL_ELE_T * sentinel, int blocking, int * _opt_err );
     505             : 
     506             : POOL_STATIC int POOL_(release)( POOL_(t) * join, POOL_ELE_T * ele, int blocking );
     507             : 
     508             : POOL_STATIC int POOL_(lock)( POOL_(t) * join, int blocking );
     509             : 
     510             : POOL_STATIC void POOL_(reset)( POOL_(t) * join, ulong sentinel_cnt );
     511             : 
     512             : POOL_STATIC FD_FN_PURE int POOL_(verify)( POOL_(t) const * join );
     513             : 
     514             : POOL_STATIC FD_FN_CONST char const * POOL_(strerror)( int err );
     515             : 
     516             : FD_PROTOTYPES_END
     517             : 
     518             : #endif
     519             : 
     520             : #if POOL_IMPL_STYLE!=1 /* need implementations (assumes header already included) */
     521             : 
     522             : #include "../log/fd_log.h" /* used by constructors and verify (FIXME: Consider making a compile time option) */
     523             : 
     524             : POOL_STATIC void *
     525          12 : POOL_(new)( void * shmem ) {
     526          12 :   POOL_(shmem_t) * pool = (POOL_(shmem_t) *)shmem;
     527             : 
     528          12 :   if( FD_UNLIKELY( !pool ) ) {
     529           3 :     FD_LOG_WARNING(( "NULL shmem" ));
     530           3 :     return NULL;
     531           3 :   }
     532             : 
     533           9 :   if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)pool, POOL_(align)() ) ) ) {
     534           3 :     FD_LOG_WARNING(( "misaligned shmem" ));
     535           3 :     return NULL;
     536           3 :   }
     537             : 
     538           6 :   pool->ver_top = POOL_(private_vidx)( 0UL, POOL_(idx_null)() );
     539             : 
     540           6 :   FD_COMPILER_MFENCE();
     541           6 :   pool->magic = POOL_MAGIC;
     542           6 :   FD_COMPILER_MFENCE();
     543             : 
     544           6 :   return (void *)pool;
     545           9 : }
     546             : 
     547             : POOL_STATIC POOL_(t) *
     548             : POOL_(join)( void * ljoin,
     549             :              void * shpool,
     550             :              void * shele,
     551          30 :              ulong  ele_max ) {
     552          30 :   POOL_(t)       * join = (POOL_(t)       *)ljoin;
     553          30 :   POOL_(shmem_t) * pool = (POOL_(shmem_t) *)shpool;
     554          30 :   POOL_ELE_T     * ele  = (POOL_ELE_T     *)shele;
     555             : 
     556          30 :   if( FD_UNLIKELY( !join ) ) {
     557           3 :     FD_LOG_WARNING(( "NULL ljoin" ));
     558           3 :     return NULL;
     559           3 :   }
     560             : 
     561          27 :   if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)join, alignof(POOL_(t)) ) ) ) {
     562           3 :     FD_LOG_WARNING(( "misaligned ljoin" ));
     563           3 :     return NULL;
     564           3 :   }
     565             : 
     566          24 :   if( FD_UNLIKELY( !pool ) ) {
     567           3 :     FD_LOG_WARNING(( "NULL shpool" ));
     568           3 :     return NULL;
     569           3 :   }
     570             : 
     571          21 :   if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)pool, POOL_(align)() ) ) ) {
     572           3 :     FD_LOG_WARNING(( "misaligned shpool" ));
     573           3 :     return NULL;
     574           3 :   }
     575             : 
     576          18 :   if( FD_UNLIKELY( pool->magic!=POOL_MAGIC ) ) {
     577           3 :     FD_LOG_WARNING(( "bad magic" ));
     578           3 :     return NULL;
     579           3 :   }
     580             : 
     581          15 :   if( FD_UNLIKELY( (!ele) & (!!ele_max) ) ) {
     582           3 :     FD_LOG_WARNING(( "NULL shele" ));
     583           3 :     return NULL;
     584           3 :   }
     585             : 
     586          12 :   if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)ele, alignof(POOL_ELE_T) ) ) ) {
     587           3 :     FD_LOG_WARNING(( "misaligned shele" ));
     588           3 :     return NULL;
     589           3 :   }
     590             : 
     591           9 :   if( FD_UNLIKELY( ele_max>POOL_(ele_max_max)() ) ) {
     592           3 :     FD_LOG_WARNING(( "bad ele_max" ));
     593           3 :     return NULL;
     594           3 :   }
     595             : 
     596           6 :   join->pool    = pool;
     597           6 :   join->ele     = ele;
     598           6 :   join->ele_max = ele_max;
     599             : 
     600           6 :   return join;
     601           9 : }
     602             : 
     603             : POOL_STATIC void *
     604           9 : POOL_(leave)( POOL_(t) * join ) {
     605             : 
     606           9 :   if( FD_UNLIKELY( !join ) ) {
     607           3 :     FD_LOG_WARNING(( "NULL join" ));
     608           3 :     return NULL;
     609           3 :   }
     610             : 
     611           6 :   return (void *)join;
     612           9 : }
     613             : 
     614             : POOL_STATIC void *
     615          15 : POOL_(delete)( void * shpool ) {
     616          15 :   POOL_(shmem_t) * pool = (POOL_(shmem_t) *)shpool;
     617             : 
     618          15 :   if( FD_UNLIKELY( !pool) ) {
     619           3 :     FD_LOG_WARNING(( "NULL shpool" ));
     620           3 :     return NULL;
     621           3 :   }
     622             : 
     623          12 :   if( FD_UNLIKELY( !fd_ulong_is_aligned( (ulong)pool, POOL_(align)() ) ) ) {
     624           3 :     FD_LOG_WARNING(( "misaligned shpool" ));
     625           3 :     return NULL;
     626           3 :   }
     627             : 
     628           9 :   if( FD_UNLIKELY( pool->magic!=POOL_MAGIC ) ) {
     629           3 :     FD_LOG_WARNING(( "bad magic" ));
     630           3 :     return NULL;
     631           3 :   }
     632             : 
     633           6 :   FD_COMPILER_MFENCE();
     634           6 :   pool->magic = 0UL;
     635           6 :   FD_COMPILER_MFENCE();
     636             : 
     637           6 :   return (void *)pool;
     638           9 : }
     639             : 
     640             : POOL_STATIC POOL_ELE_T *
     641             : POOL_(acquire)( POOL_(t) *   join,
     642             :                 POOL_ELE_T * sentinel,
     643             :                 int          blocking,
     644     3664155 :                 int *        _opt_err ) {
     645     3664155 :   POOL_ELE_T *     ele0    = join->ele;
     646     3664155 :   ulong            ele_max = join->ele_max;
     647     3664155 :   ulong volatile * _v      = (ulong volatile *)&join->pool->ver_top;
     648             : 
     649     3664155 :   POOL_ELE_T * ele = sentinel;
     650     3664155 :   int          err = FD_POOL_SUCCESS;
     651             : 
     652     3664155 :   FD_COMPILER_MFENCE();
     653             : 
     654     3664155 :   for(;;) {
     655     3664155 :     ulong ver_top = *_v;
     656             : 
     657     3664155 :     ulong ver     = POOL_(private_vidx_ver)( ver_top );
     658     3664155 :     ulong ele_idx = POOL_(private_vidx_idx)( ver_top );
     659             : 
     660     3664155 :     if( FD_LIKELY( !(ver & 1UL) ) ) { /* opt for unlocked */
     661             : 
     662     3664155 :       if( FD_UNLIKELY( POOL_(idx_is_null)( ele_idx ) ) ) { /* opt for not empty */
     663        3669 :         err = FD_POOL_ERR_EMPTY;
     664        3669 :         break;
     665        3669 :       }
     666             : 
     667     3660486 :       if( FD_UNLIKELY( ele_idx>=ele_max ) ) { /* opt for not corrupt */
     668           0 :         err = FD_POOL_ERR_CORRUPT;
     669           0 :         break;
     670           0 :       }
     671             : 
     672     3660486 :       ulong ele_nxt = POOL_(private_idx)( ele0[ ele_idx ].POOL_NEXT );
     673             : 
     674     3660486 :       if( FD_UNLIKELY( (ele_nxt>=ele_max) & (!POOL_(idx_is_null)( ele_nxt )) ) ) { /* opt for not corrupt */
     675           0 :         err = FD_POOL_ERR_CORRUPT;
     676           0 :         break;
     677           0 :       }
     678             : 
     679     3660486 :       ulong new_ver_top = POOL_(private_vidx)( ver+2UL, ele_nxt );
     680             : 
     681     3660486 :       if( FD_LIKELY( POOL_(private_cas)( _v, ver_top, new_ver_top )==ver_top ) ) { /* opt for low contention */
     682     3660486 :         ele = ele0 + ele_idx;
     683     3660486 :         break;
     684     3660486 :       }
     685             : 
     686     3660486 :     } else if( FD_UNLIKELY( !blocking ) ) { /* opt for blocking */
     687             : 
     688           0 :       err = FD_POOL_ERR_AGAIN;
     689           0 :       break; /* opt for blocking */
     690             : 
     691           0 :     }
     692             : 
     693           0 :     FD_SPIN_PAUSE();
     694           0 :   }
     695             : 
     696     3664155 :   FD_COMPILER_MFENCE();
     697             : 
     698     3664155 :   fd_int_store_if( !!_opt_err, _opt_err, err );
     699     3664155 :   return ele;
     700     3664155 : }
     701             : 
     702             : POOL_STATIC int
     703             : POOL_(release)( POOL_(t) *   join,
     704             :                 POOL_ELE_T * ele,
     705     3661263 :                 int          blocking ) {
     706     3661263 :   ulong            ele_max = join->ele_max;
     707     3661263 :   ulong volatile * _v      = (ulong volatile *)&join->pool->ver_top;
     708             : 
     709     3661263 :   ulong ele_idx = (ulong)(ele - join->ele);
     710             : 
     711     3661263 :   if( FD_UNLIKELY( ele_idx>=ele_max ) ) return FD_POOL_ERR_INVAL; /* opt for valid call */
     712             : 
     713     3660486 :   int err = FD_POOL_SUCCESS;
     714             : 
     715     3660486 :   FD_COMPILER_MFENCE();
     716             : 
     717     3660486 :   for(;;) {
     718     3660486 :     ulong ver_top = *_v;
     719             : 
     720     3660486 :     ulong ver     = POOL_(private_vidx_ver)( ver_top );
     721     3660486 :     ulong ele_nxt = POOL_(private_vidx_idx)( ver_top );
     722             : 
     723     3660486 :     if( FD_LIKELY( !(ver & 1UL) ) ) { /* opt for unlocked */
     724             : 
     725     3660486 :       if( FD_UNLIKELY( (ele_nxt>=ele_max) & (!POOL_(idx_is_null)( ele_nxt )) ) ) { /* opt for not corrupt */
     726           0 :         err = FD_POOL_ERR_CORRUPT;
     727           0 :         break;
     728           0 :       }
     729             : 
     730     3660486 :       ele->POOL_NEXT = POOL_(private_cidx)( ele_nxt );
     731             : 
     732     3660486 :       ulong new_ver_top = POOL_(private_vidx)( ver+2UL, ele_idx );
     733             : 
     734     3660486 :       if( FD_LIKELY( POOL_(private_cas)( _v, ver_top, new_ver_top )==ver_top ) ) break; /* opt for low contention */
     735             : 
     736     3660486 :     } else if( FD_UNLIKELY( !blocking ) ) { /* opt for blocking */
     737             : 
     738           0 :       err = FD_POOL_ERR_AGAIN;
     739           0 :       break;
     740             : 
     741           0 :     }
     742             : 
     743           0 :     FD_SPIN_PAUSE();
     744           0 :   }
     745             : 
     746     3660486 :   FD_COMPILER_MFENCE();
     747             : 
     748     3660486 :   return err;
     749     3661263 : }
     750             : 
     751             : POOL_STATIC int
     752             : POOL_(lock)( POOL_(t) * join,
     753           6 :              int        blocking ) {
     754           6 :   ulong volatile * _v = (ulong volatile *)&join->pool->ver_top;
     755             : 
     756           6 :   int err = FD_POOL_SUCCESS;
     757             : 
     758           6 :   FD_COMPILER_MFENCE();
     759             : 
     760           6 :   for(;;) {
     761             : 
     762             :     /* use a test-and-test-and-set style for reduced contention */
     763             : 
     764           6 :     ulong ver_top = *_v;
     765           6 :     if( FD_LIKELY( !(ver_top & (1UL<<POOL_IDX_WIDTH)) ) ) { /* opt for low contention */
     766           3 :       ver_top = POOL_(private_fetch_and_or)( _v, 1UL<<POOL_IDX_WIDTH );
     767           3 :       if( FD_LIKELY( !(ver_top & (1UL<<POOL_IDX_WIDTH)) ) ) break; /* opt for low contention */
     768           3 :     }
     769             : 
     770           3 :     if( FD_UNLIKELY( !blocking ) ) { /* opt for blocking */
     771           3 :       err = FD_POOL_ERR_AGAIN;
     772           3 :       break;
     773           3 :     }
     774             : 
     775           0 :     FD_SPIN_PAUSE();
     776           0 :   }
     777             : 
     778           6 :   FD_COMPILER_MFENCE();
     779             : 
     780           6 :   return err;
     781           6 : }
     782             : 
     783             : POOL_STATIC void
     784             : POOL_(reset)( POOL_(t) * join,
     785          15 :               ulong      sentinel_cnt ) {
     786          15 :   POOL_(shmem_t) * pool    = join->pool;
     787          15 :   POOL_ELE_T *     ele     = join->ele;
     788          15 :   ulong            ele_max = join->ele_max;
     789             : 
     790             :   /* Insert all but the leading sentinel_cnt elements in increasing
     791             :      order */
     792             : 
     793          15 :   ulong ele_top;
     794             : 
     795          15 :   if( FD_UNLIKELY( sentinel_cnt>=ele_max ) ) ele_top = POOL_(idx_null)(); /* All items are sentinels */
     796           9 :   else { /* Note: ele_max at least 1 here */
     797           9 :     ele_top = sentinel_cnt;
     798        9213 :     for( ulong ele_idx=ele_top; ele_idx<(ele_max-1UL); ele_idx++ )
     799        9204 :       ele[ ele_idx ].POOL_NEXT = POOL_(private_cidx)( ele_idx+1UL );
     800           9 :     ele[ ele_max-1UL ].POOL_NEXT = POOL_(private_cidx)( POOL_(idx_null)() );
     801           9 :   }
     802             : 
     803          15 :   ulong ver_top = pool->ver_top;
     804          15 :   ulong ver     = POOL_(private_vidx_ver)( ver_top );
     805          15 :   pool->ver_top = POOL_(private_vidx)( ver, ele_top );
     806          15 : }
     807             : 
     808             : POOL_STATIC int
     809          12 : POOL_(verify)( POOL_(t) const * join ) {
     810             : 
     811        3177 : # define POOL_TEST(c) do {                                                                        \
     812        3177 :     if( FD_UNLIKELY( !(c) ) ) { FD_LOG_WARNING(( "FAIL: %s", #c )); return FD_POOL_ERR_CORRUPT; } \
     813        3177 :   } while(0)
     814             : 
     815             :   /* Validate join */
     816             : 
     817          12 :   POOL_TEST( join );
     818          12 :   POOL_TEST( fd_ulong_is_aligned( (ulong)join, alignof(POOL_(t)) ) );
     819             : 
     820          12 :   POOL_(shmem_t) const * pool    = join->pool;
     821          12 :   POOL_ELE_T const *     ele     = join->ele;
     822          12 :   ulong                  ele_max = join->ele_max;
     823             : 
     824          12 :   POOL_TEST( pool );
     825          12 :   POOL_TEST( fd_ulong_is_aligned( (ulong)pool, POOL_(align)() ) );
     826             : 
     827          12 :   POOL_TEST( (!!ele)| (!ele_max) );
     828          12 :   POOL_TEST( fd_ulong_is_aligned( (ulong)ele, alignof(POOL_ELE_T) ) );
     829             : 
     830          12 :   POOL_TEST( ele_max<=POOL_(ele_max_max)() );
     831             : 
     832             :   /* Validate pool metadata */
     833             : 
     834          12 :   ulong magic   = pool->magic;
     835          12 :   ulong ver_top = pool->ver_top;
     836             : 
     837             :   /* version arbitrary as far as verify is concerned */
     838          12 :   ulong ele_idx = POOL_(private_vidx_idx)( ver_top );
     839             : 
     840          12 :   POOL_TEST( magic==POOL_MAGIC );
     841             : 
     842             :   /*  Validate pool elements */
     843             : 
     844          12 :   ulong ele_rem = ele_max;
     845        3081 :   while( ele_idx<ele_max ) {
     846        3069 :     POOL_TEST( ele_rem ); ele_rem--; /* no cycles */
     847        3069 :     ele_idx = POOL_(private_idx)( ele[ ele_idx ].POOL_NEXT );
     848        3069 :   }
     849             : 
     850          12 :   POOL_TEST( POOL_(idx_is_null)( ele_idx ) );
     851             : 
     852          12 : # undef POOL_TEST
     853             : 
     854          12 :   return FD_POOL_SUCCESS;
     855          12 : }
     856             : 
     857             : POOL_STATIC char const *
     858          18 : POOL_(strerror)( int err ) {
     859          18 :   switch( err ) {
     860           3 :   case FD_POOL_SUCCESS:     return "success";
     861           3 :   case FD_POOL_ERR_INVAL:   return "bad input";
     862           3 :   case FD_POOL_ERR_AGAIN:   return "try again";
     863           3 :   case FD_POOL_ERR_CORRUPT: return "corruption detected";
     864           3 :   case FD_POOL_ERR_EMPTY:   return "pool empty";
     865           3 :   default: break;
     866          18 :   }
     867           3 :   return "unknown";
     868          18 : }
     869             : 
     870             : #endif
     871             : 
     872             : #undef POOL_
     873             : #undef POOL_STATIC
     874             : #undef POOL_VER_WIDTH
     875             : 
     876             : #undef POOL_IMPL_STYLE
     877             : #undef POOL_MAGIC
     878             : #undef POOL_IDX_WIDTH
     879             : #undef POOL_ALIGN
     880             : #undef POOL_NEXT
     881             : #undef POOL_IDX_T
     882             : #undef POOL_ELE_T
     883             : #undef POOL_NAME

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