mirror of
https://github.com/golang/go
synced 2024-11-20 04:34:41 -07:00
1064 lines
18 KiB
C
1064 lines
18 KiB
C
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "runtime.h"
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#include "type.h"
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static int32 debug = 0;
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enum
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{
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Wclosed = 0x0001, // writer has closed
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Rclosed = 0x0002, // reader has seen close
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Eincr = 0x0004, // increment errors
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Emax = 0x0800, // error limit before throw
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};
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typedef struct Link Link;
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typedef struct WaitQ WaitQ;
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typedef struct SudoG SudoG;
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typedef struct Select Select;
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typedef struct Scase Scase;
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struct SudoG
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{
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G* g; // g and selgen constitute
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uint32 selgen; // a weak pointer to g
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int16 offset; // offset of case number
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int8 isfree; // offset of case number
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SudoG* link;
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byte elem[8]; // synch data element (+ more)
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};
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struct WaitQ
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{
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SudoG* first;
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SudoG* last;
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};
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struct Hchan
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{
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uint32 qcount; // total data in the q
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uint32 dataqsiz; // size of the circular q
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uint16 elemsize;
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uint16 closed; // Wclosed Rclosed errorcount
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uint8 elemalign;
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Alg* elemalg; // interface for element type
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Link* senddataq; // pointer for sender
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Link* recvdataq; // pointer for receiver
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WaitQ recvq; // list of recv waiters
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WaitQ sendq; // list of send waiters
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SudoG* free; // freelist
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Lock;
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};
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struct Link
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{
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Link* link; // asynch queue circular linked list
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byte elem[8]; // asynch queue data element (+ more)
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};
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struct Scase
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{
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Hchan* chan; // chan
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byte* pc; // return pc
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uint16 send; // 0-recv 1-send 2-default
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uint16 so; // vararg of selected bool
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union {
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byte elem[8]; // element (send)
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byte* elemp; // pointer to element (recv)
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} u;
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};
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struct Select
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{
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uint16 tcase; // total count of scase[]
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uint16 ncase; // currently filled scase[]
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Select* link; // for freelist
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Scase* scase[1]; // one per case
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};
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static void dequeueg(WaitQ*, Hchan*);
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static SudoG* dequeue(WaitQ*, Hchan*);
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static void enqueue(WaitQ*, SudoG*);
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static SudoG* allocsg(Hchan*);
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static void freesg(Hchan*, SudoG*);
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static uint32 gcd(uint32, uint32);
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static uint32 fastrand1(void);
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static uint32 fastrand2(void);
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static void destroychan(Hchan*);
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Hchan*
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makechan(Type *elem, int64 hint)
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{
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Hchan *c;
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int32 i;
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if(hint < 0 || (int32)hint != hint || hint > ((uintptr)-1) / elem->size)
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panicstring("makechan: size out of range");
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if(elem->alg >= nelem(algarray)) {
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printf("chan(alg=%d)\n", elem->alg);
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throw("runtime.makechan: unsupported elem type");
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}
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c = mal(sizeof(*c));
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addfinalizer(c, destroychan, 0);
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c->elemsize = elem->size;
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c->elemalg = &algarray[elem->alg];
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c->elemalign = elem->align;
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if(hint > 0) {
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Link *d, *b, *e;
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// make a circular q
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b = nil;
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e = nil;
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for(i=0; i<hint; i++) {
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d = mal(sizeof(*d) + c->elemsize - sizeof(d->elem));
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if(e == nil)
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e = d;
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d->link = b;
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b = d;
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}
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e->link = b;
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c->recvdataq = b;
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c->senddataq = b;
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c->qcount = 0;
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c->dataqsiz = hint;
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}
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if(debug)
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printf("makechan: chan=%p; elemsize=%D; elemalg=%d; elemalign=%d; dataqsiz=%d\n",
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c, (int64)elem->size, elem->alg, elem->align, c->dataqsiz);
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return c;
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}
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static void
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destroychan(Hchan *c)
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{
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destroylock(&c->Lock);
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}
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// makechan(elem *Type, hint int64) (hchan *chan any);
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void
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·makechan(Type *elem, int64 hint, Hchan *ret)
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{
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ret = makechan(elem, hint);
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FLUSH(&ret);
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}
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static void
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incerr(Hchan* c)
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{
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c->closed += Eincr;
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if(c->closed & Emax) {
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// Note that channel locks may still be held at this point.
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throw("too many operations on a closed channel");
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}
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}
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/*
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* generic single channel send/recv
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* if the bool pointer is nil,
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* then the full exchange will
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* occur. if pres is not nil,
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* then the protocol will not
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* sleep but return if it could
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* not complete.
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*
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* sleep can wake up with g->param == nil
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* when a channel involved in the sleep has
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* been closed. it is easiest to loop and re-run
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* the operation; we'll see that it's now closed.
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*/
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void
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chansend(Hchan *c, byte *ep, bool *pres)
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{
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SudoG *sg;
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G* gp;
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if(c == nil)
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panicstring("send to nil channel");
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if(gcwaiting)
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gosched();
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if(debug) {
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printf("chansend: chan=%p; elem=", c);
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c->elemalg->print(c->elemsize, ep);
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prints("\n");
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}
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lock(c);
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loop:
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if(c->closed & Wclosed)
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goto closed;
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if(c->dataqsiz > 0)
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goto asynch;
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sg = dequeue(&c->recvq, c);
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if(sg != nil) {
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if(ep != nil)
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c->elemalg->copy(c->elemsize, sg->elem, ep);
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gp = sg->g;
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gp->param = sg;
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unlock(c);
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ready(gp);
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if(pres != nil)
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*pres = true;
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return;
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}
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if(pres != nil) {
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unlock(c);
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*pres = false;
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return;
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}
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sg = allocsg(c);
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if(ep != nil)
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c->elemalg->copy(c->elemsize, sg->elem, ep);
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g->param = nil;
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g->status = Gwaiting;
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enqueue(&c->sendq, sg);
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unlock(c);
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gosched();
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lock(c);
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sg = g->param;
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if(sg == nil)
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goto loop;
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freesg(c, sg);
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unlock(c);
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return;
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asynch:
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if(c->closed & Wclosed)
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goto closed;
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if(c->qcount >= c->dataqsiz) {
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if(pres != nil) {
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unlock(c);
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*pres = false;
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return;
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}
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sg = allocsg(c);
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g->status = Gwaiting;
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enqueue(&c->sendq, sg);
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unlock(c);
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gosched();
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lock(c);
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goto asynch;
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}
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if(ep != nil)
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c->elemalg->copy(c->elemsize, c->senddataq->elem, ep);
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c->senddataq = c->senddataq->link;
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c->qcount++;
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sg = dequeue(&c->recvq, c);
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if(sg != nil) {
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gp = sg->g;
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freesg(c, sg);
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unlock(c);
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ready(gp);
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} else
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unlock(c);
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if(pres != nil)
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*pres = true;
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return;
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closed:
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incerr(c);
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if(pres != nil)
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*pres = true;
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unlock(c);
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}
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void
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chanrecv(Hchan* c, byte *ep, bool* pres)
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{
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SudoG *sg;
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G *gp;
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if(c == nil)
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panicstring("receive from nil channel");
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if(gcwaiting)
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gosched();
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if(debug)
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printf("chanrecv: chan=%p\n", c);
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lock(c);
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loop:
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if(c->dataqsiz > 0)
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goto asynch;
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if(c->closed & Wclosed)
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goto closed;
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sg = dequeue(&c->sendq, c);
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if(sg != nil) {
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c->elemalg->copy(c->elemsize, ep, sg->elem);
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c->elemalg->copy(c->elemsize, sg->elem, nil);
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gp = sg->g;
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gp->param = sg;
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unlock(c);
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ready(gp);
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if(pres != nil)
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*pres = true;
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return;
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}
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if(pres != nil) {
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unlock(c);
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c->elemalg->copy(c->elemsize, ep, nil);
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*pres = false;
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return;
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}
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sg = allocsg(c);
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g->param = nil;
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g->status = Gwaiting;
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enqueue(&c->recvq, sg);
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unlock(c);
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gosched();
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lock(c);
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sg = g->param;
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if(sg == nil)
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goto loop;
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c->elemalg->copy(c->elemsize, ep, sg->elem);
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c->elemalg->copy(c->elemsize, sg->elem, nil);
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freesg(c, sg);
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unlock(c);
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return;
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asynch:
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if(c->qcount <= 0) {
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if(c->closed & Wclosed)
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goto closed;
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if(pres != nil) {
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unlock(c);
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c->elemalg->copy(c->elemsize, ep, nil);
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*pres = false;
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return;
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}
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sg = allocsg(c);
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g->status = Gwaiting;
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enqueue(&c->recvq, sg);
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unlock(c);
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gosched();
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lock(c);
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goto asynch;
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}
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c->elemalg->copy(c->elemsize, ep, c->recvdataq->elem);
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c->elemalg->copy(c->elemsize, c->recvdataq->elem, nil);
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c->recvdataq = c->recvdataq->link;
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c->qcount--;
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sg = dequeue(&c->sendq, c);
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if(sg != nil) {
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gp = sg->g;
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freesg(c, sg);
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unlock(c);
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ready(gp);
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if(pres != nil)
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*pres = true;
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return;
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}
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unlock(c);
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if(pres != nil)
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*pres = true;
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return;
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closed:
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c->elemalg->copy(c->elemsize, ep, nil);
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c->closed |= Rclosed;
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incerr(c);
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if(pres != nil)
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*pres = true;
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unlock(c);
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}
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// chansend1(hchan *chan any, elem any);
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#pragma textflag 7
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void
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·chansend1(Hchan* c, ...)
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{
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int32 o;
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byte *ae;
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o = rnd(sizeof(c), c->elemalign);
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ae = (byte*)&c + o;
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chansend(c, ae, nil);
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}
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// chansend2(hchan *chan any, elem any) (pres bool);
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#pragma textflag 7
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void
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·chansend2(Hchan* c, ...)
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{
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int32 o;
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byte *ae, *ap;
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o = rnd(sizeof(c), c->elemalign);
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ae = (byte*)&c + o;
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o = rnd(o+c->elemsize, Structrnd);
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ap = (byte*)&c + o;
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chansend(c, ae, ap);
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}
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// chanrecv1(hchan *chan any) (elem any);
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#pragma textflag 7
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void
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·chanrecv1(Hchan* c, ...)
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{
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int32 o;
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byte *ae;
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o = rnd(sizeof(c), Structrnd);
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ae = (byte*)&c + o;
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chanrecv(c, ae, nil);
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}
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// chanrecv2(hchan *chan any) (elem any, pres bool);
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#pragma textflag 7
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void
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·chanrecv2(Hchan* c, ...)
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{
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int32 o;
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byte *ae, *ap;
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o = rnd(sizeof(c), Structrnd);
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ae = (byte*)&c + o;
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o = rnd(o+c->elemsize, 1);
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ap = (byte*)&c + o;
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chanrecv(c, ae, ap);
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}
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// newselect(size uint32) (sel *byte);
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#pragma textflag 7
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void
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·newselect(int32 size, ...)
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{
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int32 n, o;
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Select **selp;
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Select *sel;
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o = rnd(sizeof(size), Structrnd);
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selp = (Select**)((byte*)&size + o);
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n = 0;
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if(size > 1)
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n = size-1;
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sel = mal(sizeof(*sel) + n*sizeof(sel->scase[0]));
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sel->tcase = size;
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sel->ncase = 0;
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*selp = sel;
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if(debug)
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printf("newselect s=%p size=%d\n", sel, size);
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}
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// selectsend(sel *byte, hchan *chan any, elem any) (selected bool);
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#pragma textflag 7
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void
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·selectsend(Select *sel, Hchan *c, ...)
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{
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int32 i, eo;
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Scase *cas;
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byte *ae;
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// nil cases do not compete
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if(c == nil)
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return;
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i = sel->ncase;
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if(i >= sel->tcase)
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throw("selectsend: too many cases");
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sel->ncase = i+1;
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cas = mal(sizeof *cas + c->elemsize - sizeof(cas->u.elem));
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sel->scase[i] = cas;
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cas->pc = ·getcallerpc(&sel);
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cas->chan = c;
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eo = rnd(sizeof(sel), sizeof(c));
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eo = rnd(eo+sizeof(c), c->elemsize);
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cas->so = rnd(eo+c->elemsize, Structrnd);
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cas->send = 1;
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ae = (byte*)&sel + eo;
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c->elemalg->copy(c->elemsize, cas->u.elem, ae);
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if(debug)
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printf("selectsend s=%p pc=%p chan=%p so=%d send=%d\n",
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sel, cas->pc, cas->chan, cas->so, cas->send);
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}
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|
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// selectrecv(sel *byte, hchan *chan any, elem *any) (selected bool);
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#pragma textflag 7
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void
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·selectrecv(Select *sel, Hchan *c, ...)
|
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{
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int32 i, eo;
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Scase *cas;
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|
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// nil cases do not compete
|
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if(c == nil)
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return;
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i = sel->ncase;
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if(i >= sel->tcase)
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throw("selectrecv: too many cases");
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sel->ncase = i+1;
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cas = mal(sizeof *cas);
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sel->scase[i] = cas;
|
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cas->pc = ·getcallerpc(&sel);
|
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cas->chan = c;
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|
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eo = rnd(sizeof(sel), sizeof(c));
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eo = rnd(eo+sizeof(c), sizeof(byte*));
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cas->so = rnd(eo+sizeof(byte*), Structrnd);
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cas->send = 0;
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cas->u.elemp = *(byte**)((byte*)&sel + eo);
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|
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if(debug)
|
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printf("selectrecv s=%p pc=%p chan=%p so=%d send=%d\n",
|
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sel, cas->pc, cas->chan, cas->so, cas->send);
|
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}
|
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|
|
|
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// selectdefaul(sel *byte) (selected bool);
|
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#pragma textflag 7
|
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void
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·selectdefault(Select *sel, ...)
|
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{
|
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int32 i;
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Scase *cas;
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|
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i = sel->ncase;
|
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if(i >= sel->tcase)
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throw("selectdefault: too many cases");
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sel->ncase = i+1;
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cas = mal(sizeof *cas);
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sel->scase[i] = cas;
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cas->pc = ·getcallerpc(&sel);
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cas->chan = nil;
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|
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cas->so = rnd(sizeof(sel), Structrnd);
|
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cas->send = 2;
|
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cas->u.elemp = nil;
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|
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if(debug)
|
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printf("selectdefault s=%p pc=%p so=%d send=%d\n",
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sel, cas->pc, cas->so, cas->send);
|
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}
|
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|
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static void
|
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freesel(Select *sel)
|
|
{
|
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uint32 i;
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|
|
for(i=0; i<sel->ncase; i++)
|
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free(sel->scase[i]);
|
|
free(sel);
|
|
}
|
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|
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static void
|
|
sellock(Select *sel)
|
|
{
|
|
uint32 i;
|
|
Hchan *c;
|
|
|
|
c = nil;
|
|
for(i=0; i<sel->ncase; i++) {
|
|
if(sel->scase[i]->chan != c) {
|
|
c = sel->scase[i]->chan;
|
|
lock(c);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
selunlock(Select *sel)
|
|
{
|
|
uint32 i;
|
|
Hchan *c;
|
|
|
|
c = nil;
|
|
for(i=sel->ncase; i>0; i--) {
|
|
if(sel->scase[i-1]->chan && sel->scase[i-1]->chan != c) {
|
|
c = sel->scase[i-1]->chan;
|
|
unlock(c);
|
|
}
|
|
}
|
|
}
|
|
|
|
// selectgo(sel *byte);
|
|
void
|
|
·selectgo(Select *sel)
|
|
{
|
|
uint32 p, o, i, j;
|
|
Scase *cas, *dfl;
|
|
Hchan *c;
|
|
SudoG *sg;
|
|
G *gp;
|
|
byte *as;
|
|
|
|
if(gcwaiting)
|
|
gosched();
|
|
|
|
if(debug)
|
|
printf("select: sel=%p\n", sel);
|
|
|
|
if(sel->ncase < 2) {
|
|
if(sel->ncase < 1)
|
|
throw("select: no cases");
|
|
// make special case of one.
|
|
}
|
|
|
|
// select a (relative) prime
|
|
for(i=0;; i++) {
|
|
p = fastrand1();
|
|
if(gcd(p, sel->ncase) == 1)
|
|
break;
|
|
if(i > 1000)
|
|
throw("select: failed to select prime");
|
|
}
|
|
|
|
// select an initial offset
|
|
o = fastrand2();
|
|
|
|
p %= sel->ncase;
|
|
o %= sel->ncase;
|
|
|
|
// sort the cases by Hchan address to get the locking order.
|
|
for(i=1; i<sel->ncase; i++) {
|
|
cas = sel->scase[i];
|
|
for(j=i; j>0 && sel->scase[j-1]->chan >= cas->chan; j--)
|
|
sel->scase[j] = sel->scase[j-1];
|
|
sel->scase[j] = cas;
|
|
}
|
|
|
|
sellock(sel);
|
|
|
|
loop:
|
|
// pass 1 - look for something already waiting
|
|
dfl = nil;
|
|
for(i=0; i<sel->ncase; i++) {
|
|
cas = sel->scase[o];
|
|
c = cas->chan;
|
|
|
|
switch(cas->send) {
|
|
case 0: // recv
|
|
if(c->dataqsiz > 0) {
|
|
if(c->qcount > 0)
|
|
goto asyncrecv;
|
|
} else {
|
|
sg = dequeue(&c->sendq, c);
|
|
if(sg != nil)
|
|
goto syncrecv;
|
|
}
|
|
if(c->closed & Wclosed)
|
|
goto rclose;
|
|
break;
|
|
|
|
case 1: // send
|
|
if(c->closed & Wclosed)
|
|
goto sclose;
|
|
if(c->dataqsiz > 0) {
|
|
if(c->qcount < c->dataqsiz)
|
|
goto asyncsend;
|
|
} else {
|
|
sg = dequeue(&c->recvq, c);
|
|
if(sg != nil)
|
|
goto syncsend;
|
|
}
|
|
break;
|
|
|
|
case 2: // default
|
|
dfl = cas;
|
|
break;
|
|
}
|
|
|
|
o += p;
|
|
if(o >= sel->ncase)
|
|
o -= sel->ncase;
|
|
}
|
|
|
|
if(dfl != nil) {
|
|
cas = dfl;
|
|
goto retc;
|
|
}
|
|
|
|
|
|
// pass 2 - enqueue on all chans
|
|
for(i=0; i<sel->ncase; i++) {
|
|
cas = sel->scase[o];
|
|
c = cas->chan;
|
|
sg = allocsg(c);
|
|
sg->offset = o;
|
|
|
|
switch(cas->send) {
|
|
case 0: // recv
|
|
if(c->dataqsiz > 0) {
|
|
if(c->qcount > 0)
|
|
throw("select: pass 2 async recv");
|
|
} else {
|
|
if(dequeue(&c->sendq, c))
|
|
throw("select: pass 2 sync recv");
|
|
}
|
|
enqueue(&c->recvq, sg);
|
|
break;
|
|
|
|
case 1: // send
|
|
if(c->dataqsiz > 0) {
|
|
if(c->qcount < c->dataqsiz)
|
|
throw("select: pass 2 async send");
|
|
} else {
|
|
if(dequeue(&c->recvq, c))
|
|
throw("select: pass 2 sync send");
|
|
c->elemalg->copy(c->elemsize, sg->elem, cas->u.elem);
|
|
}
|
|
enqueue(&c->sendq, sg);
|
|
break;
|
|
}
|
|
|
|
o += p;
|
|
if(o >= sel->ncase)
|
|
o -= sel->ncase;
|
|
}
|
|
|
|
g->param = nil;
|
|
g->status = Gwaiting;
|
|
selunlock(sel);
|
|
gosched();
|
|
|
|
sellock(sel);
|
|
sg = g->param;
|
|
|
|
// pass 3 - dequeue from unsuccessful chans
|
|
// otherwise they stack up on quiet channels
|
|
for(i=0; i<sel->ncase; i++) {
|
|
if(sg == nil || o != sg->offset) {
|
|
cas = sel->scase[o];
|
|
c = cas->chan;
|
|
if(cas->send)
|
|
dequeueg(&c->sendq, c);
|
|
else
|
|
dequeueg(&c->recvq, c);
|
|
}
|
|
|
|
o += p;
|
|
if(o >= sel->ncase)
|
|
o -= sel->ncase;
|
|
}
|
|
|
|
if(sg == nil)
|
|
goto loop;
|
|
|
|
o = sg->offset;
|
|
cas = sel->scase[o];
|
|
c = cas->chan;
|
|
|
|
if(c->dataqsiz > 0) {
|
|
// prints("shouldnt happen\n");
|
|
goto loop;
|
|
}
|
|
|
|
if(debug)
|
|
printf("wait-return: sel=%p c=%p cas=%p send=%d o=%d\n",
|
|
sel, c, cas, cas->send, o);
|
|
|
|
if(!cas->send) {
|
|
if(cas->u.elemp != nil)
|
|
c->elemalg->copy(c->elemsize, cas->u.elemp, sg->elem);
|
|
c->elemalg->copy(c->elemsize, sg->elem, nil);
|
|
}
|
|
|
|
freesg(c, sg);
|
|
goto retc;
|
|
|
|
asyncrecv:
|
|
// can receive from buffer
|
|
if(cas->u.elemp != nil)
|
|
c->elemalg->copy(c->elemsize, cas->u.elemp, c->recvdataq->elem);
|
|
c->elemalg->copy(c->elemsize, c->recvdataq->elem, nil);
|
|
c->recvdataq = c->recvdataq->link;
|
|
c->qcount--;
|
|
sg = dequeue(&c->sendq, c);
|
|
if(sg != nil) {
|
|
gp = sg->g;
|
|
freesg(c, sg);
|
|
ready(gp);
|
|
}
|
|
goto retc;
|
|
|
|
asyncsend:
|
|
// can send to buffer
|
|
if(cas->u.elem != nil)
|
|
c->elemalg->copy(c->elemsize, c->senddataq->elem, cas->u.elem);
|
|
c->senddataq = c->senddataq->link;
|
|
c->qcount++;
|
|
sg = dequeue(&c->recvq, c);
|
|
if(sg != nil) {
|
|
gp = sg->g;
|
|
freesg(c, sg);
|
|
ready(gp);
|
|
}
|
|
goto retc;
|
|
|
|
syncrecv:
|
|
// can receive from sleeping sender (sg)
|
|
if(debug)
|
|
printf("syncrecv: sel=%p c=%p o=%d\n", sel, c, o);
|
|
if(cas->u.elemp != nil)
|
|
c->elemalg->copy(c->elemsize, cas->u.elemp, sg->elem);
|
|
c->elemalg->copy(c->elemsize, sg->elem, nil);
|
|
gp = sg->g;
|
|
gp->param = sg;
|
|
ready(gp);
|
|
goto retc;
|
|
|
|
rclose:
|
|
// read at end of closed channel
|
|
if(cas->u.elemp != nil)
|
|
c->elemalg->copy(c->elemsize, cas->u.elemp, nil);
|
|
c->closed |= Rclosed;
|
|
incerr(c);
|
|
goto retc;
|
|
|
|
syncsend:
|
|
// can send to sleeping receiver (sg)
|
|
if(debug)
|
|
printf("syncsend: sel=%p c=%p o=%d\n", sel, c, o);
|
|
if(c->closed & Wclosed)
|
|
goto sclose;
|
|
c->elemalg->copy(c->elemsize, sg->elem, cas->u.elem);
|
|
gp = sg->g;
|
|
gp->param = sg;
|
|
ready(gp);
|
|
goto retc;
|
|
|
|
sclose:
|
|
// send on closed channel
|
|
incerr(c);
|
|
goto retc;
|
|
|
|
retc:
|
|
selunlock(sel);
|
|
|
|
// return to pc corresponding to chosen case
|
|
·setcallerpc(&sel, cas->pc);
|
|
as = (byte*)&sel + cas->so;
|
|
freesel(sel);
|
|
*as = true;
|
|
}
|
|
|
|
// closechan(sel *byte);
|
|
void
|
|
·closechan(Hchan *c)
|
|
{
|
|
SudoG *sg;
|
|
G* gp;
|
|
|
|
if(gcwaiting)
|
|
gosched();
|
|
|
|
lock(c);
|
|
incerr(c);
|
|
c->closed |= Wclosed;
|
|
|
|
// release all readers
|
|
for(;;) {
|
|
sg = dequeue(&c->recvq, c);
|
|
if(sg == nil)
|
|
break;
|
|
gp = sg->g;
|
|
gp->param = nil;
|
|
freesg(c, sg);
|
|
ready(gp);
|
|
}
|
|
|
|
// release all writers
|
|
for(;;) {
|
|
sg = dequeue(&c->sendq, c);
|
|
if(sg == nil)
|
|
break;
|
|
gp = sg->g;
|
|
gp->param = nil;
|
|
freesg(c, sg);
|
|
ready(gp);
|
|
}
|
|
|
|
unlock(c);
|
|
}
|
|
|
|
void
|
|
chanclose(Hchan *c)
|
|
{
|
|
·closechan(c);
|
|
}
|
|
|
|
bool
|
|
chanclosed(Hchan *c)
|
|
{
|
|
return (c->closed & Rclosed) != 0;
|
|
}
|
|
|
|
int32
|
|
chanlen(Hchan *c)
|
|
{
|
|
return c->qcount;
|
|
}
|
|
|
|
int32
|
|
chancap(Hchan *c)
|
|
{
|
|
return c->dataqsiz;
|
|
}
|
|
|
|
|
|
// closedchan(sel *byte) bool;
|
|
void
|
|
·closedchan(Hchan *c, bool closed)
|
|
{
|
|
closed = chanclosed(c);
|
|
FLUSH(&closed);
|
|
}
|
|
|
|
static SudoG*
|
|
dequeue(WaitQ *q, Hchan *c)
|
|
{
|
|
SudoG *sgp;
|
|
|
|
loop:
|
|
sgp = q->first;
|
|
if(sgp == nil)
|
|
return nil;
|
|
q->first = sgp->link;
|
|
|
|
// if sgp is stale, ignore it
|
|
if(!cas(&sgp->g->selgen, sgp->selgen, sgp->selgen + 1)) {
|
|
//prints("INVALID PSEUDOG POINTER\n");
|
|
freesg(c, sgp);
|
|
goto loop;
|
|
}
|
|
|
|
return sgp;
|
|
}
|
|
|
|
static void
|
|
dequeueg(WaitQ *q, Hchan *c)
|
|
{
|
|
SudoG **l, *sgp;
|
|
|
|
for(l=&q->first; (sgp=*l) != nil; l=&sgp->link) {
|
|
if(sgp->g == g) {
|
|
*l = sgp->link;
|
|
freesg(c, sgp);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
enqueue(WaitQ *q, SudoG *sgp)
|
|
{
|
|
sgp->link = nil;
|
|
if(q->first == nil) {
|
|
q->first = sgp;
|
|
q->last = sgp;
|
|
return;
|
|
}
|
|
q->last->link = sgp;
|
|
q->last = sgp;
|
|
}
|
|
|
|
static SudoG*
|
|
allocsg(Hchan *c)
|
|
{
|
|
SudoG* sg;
|
|
|
|
sg = c->free;
|
|
if(sg != nil) {
|
|
c->free = sg->link;
|
|
} else
|
|
sg = mal(sizeof(*sg) + c->elemsize - sizeof(sg->elem));
|
|
sg->selgen = g->selgen;
|
|
sg->g = g;
|
|
sg->offset = 0;
|
|
sg->isfree = 0;
|
|
|
|
return sg;
|
|
}
|
|
|
|
static void
|
|
freesg(Hchan *c, SudoG *sg)
|
|
{
|
|
if(sg != nil) {
|
|
if(sg->isfree)
|
|
throw("chan.freesg: already free");
|
|
sg->isfree = 1;
|
|
sg->link = c->free;
|
|
c->free = sg;
|
|
}
|
|
}
|
|
|
|
static uint32
|
|
gcd(uint32 u, uint32 v)
|
|
{
|
|
for(;;) {
|
|
if(u > v) {
|
|
if(v == 0)
|
|
return u;
|
|
u = u%v;
|
|
continue;
|
|
}
|
|
if(u == 0)
|
|
return v;
|
|
v = v%u;
|
|
}
|
|
}
|
|
|
|
static uint32
|
|
fastrand1(void)
|
|
{
|
|
static uint32 x = 0x49f6428aUL;
|
|
|
|
x += x;
|
|
if(x & 0x80000000L)
|
|
x ^= 0x88888eefUL;
|
|
return x;
|
|
}
|
|
|
|
static uint32
|
|
fastrand2(void)
|
|
{
|
|
static uint32 x = 0x49f6428aUL;
|
|
|
|
x += x;
|
|
if(x & 0x80000000L)
|
|
x ^= 0xfafd871bUL;
|
|
return x;
|
|
}
|