diff options
Diffstat (limited to 'src/pkg/runtime/sema.goc')
| -rw-r--r-- | src/pkg/runtime/sema.goc | 137 |
1 files changed, 117 insertions, 20 deletions
diff --git a/src/pkg/runtime/sema.goc b/src/pkg/runtime/sema.goc index 4df01fc4e..57f32a0dd 100644 --- a/src/pkg/runtime/sema.goc +++ b/src/pkg/runtime/sema.goc @@ -20,23 +20,25 @@ package sync #include "runtime.h" #include "arch_GOARCH.h" +#include "../../cmd/ld/textflag.h" -typedef struct Sema Sema; -struct Sema +typedef struct SemaWaiter SemaWaiter; +struct SemaWaiter { uint32 volatile* addr; G* g; int64 releasetime; - Sema* prev; - Sema* next; + int32 nrelease; // -1 for acquire + SemaWaiter* prev; + SemaWaiter* next; }; typedef struct SemaRoot SemaRoot; struct SemaRoot { Lock; - Sema* head; - Sema* tail; + SemaWaiter* head; + SemaWaiter* tail; // Number of waiters. Read w/o the lock. uint32 volatile nwait; }; @@ -49,7 +51,7 @@ struct semtable SemaRoot; uint8 pad[CacheLineSize-sizeof(SemaRoot)]; }; -#pragma dataflag 16 /* mark semtable as 'no pointers', hiding from garbage collector */ +#pragma dataflag NOPTR /* mark semtable as 'no pointers', hiding from garbage collector */ static struct semtable semtable[SEMTABLESZ]; static SemaRoot* @@ -59,7 +61,7 @@ semroot(uint32 *addr) } static void -semqueue(SemaRoot *root, uint32 volatile *addr, Sema *s) +semqueue(SemaRoot *root, uint32 volatile *addr, SemaWaiter *s) { s->g = g; s->addr = addr; @@ -73,7 +75,7 @@ semqueue(SemaRoot *root, uint32 volatile *addr, Sema *s) } static void -semdequeue(SemaRoot *root, Sema *s) +semdequeue(SemaRoot *root, SemaWaiter *s) { if(s->next) s->next->prev = s->prev; @@ -98,10 +100,10 @@ cansemacquire(uint32 *addr) return 0; } -static void -semacquireimpl(uint32 volatile *addr, int32 profile) +void +runtime·semacquire(uint32 volatile *addr, bool profile) { - Sema s; // Needs to be allocated on stack, otherwise garbage collector could deallocate it + SemaWaiter s; // Needs to be allocated on stack, otherwise garbage collector could deallocate it SemaRoot *root; int64 t0; @@ -145,15 +147,9 @@ semacquireimpl(uint32 volatile *addr, int32 profile) } void -runtime·semacquire(uint32 volatile *addr) -{ - semacquireimpl(addr, 0); -} - -void runtime·semrelease(uint32 volatile *addr) { - Sema *s; + SemaWaiter *s; SemaRoot *root; root = semroot(addr); @@ -188,10 +184,111 @@ runtime·semrelease(uint32 volatile *addr) } } +// TODO(dvyukov): move to netpoll.goc once it's used by all OSes. +void net·runtime_Semacquire(uint32 *addr) +{ + runtime·semacquire(addr, true); +} + +void net·runtime_Semrelease(uint32 *addr) +{ + runtime·semrelease(addr); +} + func runtime_Semacquire(addr *uint32) { - semacquireimpl(addr, 1); + runtime·semacquire(addr, true); } func runtime_Semrelease(addr *uint32) { runtime·semrelease(addr); } + +typedef struct SyncSema SyncSema; +struct SyncSema +{ + Lock; + SemaWaiter* head; + SemaWaiter* tail; +}; + +func runtime_Syncsemcheck(size uintptr) { + if(size != sizeof(SyncSema)) { + runtime·printf("bad SyncSema size: sync:%D runtime:%D\n", (int64)size, (int64)sizeof(SyncSema)); + runtime·throw("bad SyncSema size"); + } +} + +// Syncsemacquire waits for a pairing Syncsemrelease on the same semaphore s. +func runtime_Syncsemacquire(s *SyncSema) { + SemaWaiter w, *wake; + int64 t0; + + w.g = g; + w.nrelease = -1; + w.next = nil; + w.releasetime = 0; + t0 = 0; + if(runtime·blockprofilerate > 0) { + t0 = runtime·cputicks(); + w.releasetime = -1; + } + + runtime·lock(s); + if(s->head && s->head->nrelease > 0) { + // have pending release, consume it + wake = nil; + s->head->nrelease--; + if(s->head->nrelease == 0) { + wake = s->head; + s->head = wake->next; + if(s->head == nil) + s->tail = nil; + } + runtime·unlock(s); + if(wake) + runtime·ready(wake->g); + } else { + // enqueue itself + if(s->tail == nil) + s->head = &w; + else + s->tail->next = &w; + s->tail = &w; + runtime·park(runtime·unlock, s, "semacquire"); + if(t0) + runtime·blockevent(w.releasetime - t0, 2); + } +} + +// Syncsemrelease waits for n pairing Syncsemacquire on the same semaphore s. +func runtime_Syncsemrelease(s *SyncSema, n uint32) { + SemaWaiter w, *wake; + + w.g = g; + w.nrelease = (int32)n; + w.next = nil; + w.releasetime = 0; + + runtime·lock(s); + while(w.nrelease > 0 && s->head && s->head->nrelease < 0) { + // have pending acquire, satisfy it + wake = s->head; + s->head = wake->next; + if(s->head == nil) + s->tail = nil; + if(wake->releasetime) + wake->releasetime = runtime·cputicks(); + runtime·ready(wake->g); + w.nrelease--; + } + if(w.nrelease > 0) { + // enqueue itself + if(s->tail == nil) + s->head = &w; + else + s->tail->next = &w; + s->tail = &w; + runtime·park(runtime·unlock, s, "semarelease"); + } else + runtime·unlock(s); +} |