Use explicit allspan list instead of
trying to find all the places where
spans might be recorded.
Free can cascade into complicated
span manipulations that move them
from list to list; the old code had the
possibility of accidentally processing
a span twice or jumping to a different
list, causing an infinite loop.
R=r
DELTA=70 (28 added, 25 deleted, 17 changed)
OCL=23704
CL=23710
diff --git a/src/runtime/Makefile b/src/runtime/Makefile
index e9c895a..468a5eb 100644
--- a/src/runtime/Makefile
+++ b/src/runtime/Makefile
@@ -43,7 +43,7 @@
OFILES=$(RT0OFILES) $(LIBOFILES)
OS_H=$(GOARCH)_$(GOOS).h
-HFILES=runtime.h hashmap.h $(OS_H_)
+HFILES=runtime.h hashmap.h malloc.h $(OS_H_)
install: rt0 $(LIB) runtime.acid
cp $(RT0OFILES) $(GOROOT)/lib
diff --git a/src/runtime/malloc.c b/src/runtime/malloc.c
index e518b56..7435435 100644
--- a/src/runtime/malloc.c
+++ b/src/runtime/malloc.c
@@ -272,7 +272,7 @@
if(m->mallocing) {
lock(&stacks);
if(stacks.size == 0)
- FixAlloc_Init(&stacks, n, SysAlloc);
+ FixAlloc_Init(&stacks, n, SysAlloc, nil, nil);
if(stacks.size != n) {
printf("stackalloc: in malloc, size=%D want %d", stacks.size, n);
throw("stackalloc");
diff --git a/src/runtime/malloc.h b/src/runtime/malloc.h
index 1da9f98..d1d9e95 100644
--- a/src/runtime/malloc.h
+++ b/src/runtime/malloc.h
@@ -131,16 +131,20 @@
//
// Memory returned by FixAlloc_Alloc is not zeroed.
// The caller is responsible for locking around FixAlloc calls.
+// Callers can keep state in the object but the first word is
+// smashed by freeing and reallocating.
struct FixAlloc
{
uintptr size;
void *(*alloc)(uintptr);
+ void (*first)(void *arg, byte *p); // called first time p is returned
+ void *arg;
MLink *list;
byte *chunk;
uint32 nchunk;
};
-void FixAlloc_Init(FixAlloc *f, uintptr size, void *(*alloc)(uintptr));
+void FixAlloc_Init(FixAlloc *f, uintptr size, void *(*alloc)(uintptr), void (*first)(void*, byte*), void *arg);
void* FixAlloc_Alloc(FixAlloc *f);
void FixAlloc_Free(FixAlloc *f, void *p);
@@ -203,18 +207,21 @@
enum
{
MSpanInUse = 0,
- MSpanFree
+ MSpanFree,
+ MSpanListHead,
+ MSpanDead,
};
struct MSpan
{
MSpan *next; // in a span linked list
MSpan *prev; // in a span linked list
+ MSpan *allnext; // in the list of all spans
PageID start; // starting page number
uintptr npages; // number of pages in span
MLink *freelist; // list of free objects
uint32 ref; // number of allocated objects in this span
uint32 sizeclass; // size class
- uint32 state; // MSpanInUse or MSpanFree
+ uint32 state; // MSpanInUse etc
union {
uint32 *gcref; // sizeclass > 0
uint32 gcref0; // sizeclass == 0
@@ -349,6 +356,7 @@
Lock;
MSpan free[MaxMHeapList]; // free lists of given length
MSpan large; // free lists length >= MaxMHeapList
+ MSpan *allspans;
// span lookup
MHeapMap map;
diff --git a/src/runtime/mfixalloc.c b/src/runtime/mfixalloc.c
index 904ca7e..dd4f3f2 100644
--- a/src/runtime/mfixalloc.c
+++ b/src/runtime/mfixalloc.c
@@ -12,10 +12,12 @@
// Initialize f to allocate objects of the given size,
// using the allocator to obtain chunks of memory.
void
-FixAlloc_Init(FixAlloc *f, uintptr size, void *(*alloc)(uintptr))
+FixAlloc_Init(FixAlloc *f, uintptr size, void *(*alloc)(uintptr), void (*first)(void*, byte*), void *arg)
{
f->size = size;
f->alloc = alloc;
+ f->first = first;
+ f->arg = arg;
f->list = nil;
f->chunk = nil;
f->nchunk = 0;
@@ -38,6 +40,8 @@
f->nchunk = FixAllocChunk;
}
v = f->chunk;
+ if(f->first)
+ f->first(f->arg, v);
f->chunk += f->size;
f->nchunk -= f->size;
return v;
diff --git a/src/runtime/mgc0.c b/src/runtime/mgc0.c
index 3584bf7..ecb55b5 100644
--- a/src/runtime/mgc0.c
+++ b/src/runtime/mgc0.c
@@ -109,7 +109,7 @@
if(s->state != MSpanInUse)
return;
-
+
p = (byte*)(s->start << PageShift);
if(s->sizeclass == 0) {
// Large block.
@@ -158,32 +158,13 @@
}
static void
-sweepspanlist(MSpan *list)
-{
- MSpan *s, *next;
-
- for(s=list->next; s != list; s=next) {
- next = s->next; // in case s gets moved
- sweepspan(s);
- }
-}
-
-static void
sweep(void)
{
- int32 i;
+ MSpan *s;
// Sweep all the spans.
-
- for(i=0; i<nelem(mheap.central); i++) {
- // Sweep nonempty (has some free blocks available)
- // before sweeping empty (is completely allocated),
- // because finding something to free in a span from empty
- // will move it into nonempty, and we must not sweep
- // the same span twice.
- sweepspanlist(&mheap.central[i].nonempty);
- sweepspanlist(&mheap.central[i].empty);
- }
+ for(s = mheap.allspans; s != nil; s = s->allnext)
+ sweepspan(s);
}
// Semaphore, not Lock, so that the goroutine
diff --git a/src/runtime/mheap.c b/src/runtime/mheap.c
index d1b504e..64af8e7 100644
--- a/src/runtime/mheap.c
+++ b/src/runtime/mheap.c
@@ -21,14 +21,26 @@
static MSpan *MHeap_AllocLarge(MHeap*, uintptr);
static MSpan *BestFit(MSpan*, uintptr, MSpan*);
+static void
+RecordSpan(void *vh, byte *p)
+{
+ MHeap *h;
+ MSpan *s;
+
+ h = vh;
+ s = (MSpan*)p;
+ s->allnext = h->allspans;
+ h->allspans = s;
+}
+
// Initialize the heap; fetch memory using alloc.
void
MHeap_Init(MHeap *h, void *(*alloc)(uintptr))
{
uint32 i;
- FixAlloc_Init(&h->spanalloc, sizeof(MSpan), alloc);
- FixAlloc_Init(&h->cachealloc, sizeof(MCache), alloc);
+ FixAlloc_Init(&h->spanalloc, sizeof(MSpan), alloc, RecordSpan, h);
+ FixAlloc_Init(&h->cachealloc, sizeof(MCache), alloc, nil, nil);
MHeapMap_Init(&h->map, alloc);
// h->mapcache needs no init
for(i=0; i<nelem(h->free); i++)
@@ -110,11 +122,6 @@
for(n=0; n<npage; n++)
if(MHeapMapCache_GET(&h->mapcache, s->start+n, tmp) != 0)
MHeapMapCache_SET(&h->mapcache, s->start+n, 0);
-
- // Need a list of large allocated spans.
- // They have sizeclass == 0, so use heap.central[0].empty,
- // since central[0] is otherwise unused.
- MSpanList_Insert(&h->central[0].empty, s);
} else {
// Save cache entries for this span.
// If there's a size class, there aren't that many pages.
@@ -252,12 +259,14 @@
s->npages += t->npages;
MHeapMap_Set(&h->map, s->start, s);
MSpanList_Remove(t);
+ t->state = MSpanDead;
FixAlloc_Free(&h->spanalloc, t);
}
if((t = MHeapMap_Get(&h->map, s->start + s->npages)) != nil && t->state != MSpanInUse) {
s->npages += t->npages;
MHeapMap_Set(&h->map, s->start + s->npages - 1, s);
MSpanList_Remove(t);
+ t->state = MSpanDead;
FixAlloc_Free(&h->spanalloc, t);
}
@@ -395,6 +404,7 @@
void
MSpanList_Init(MSpan *list)
{
+ list->state = MSpanListHead;
list->next = list;
list->prev = list;
}
diff --git a/src/runtime/proc.c b/src/runtime/proc.c
index 349074b..fc011cf 100644
--- a/src/runtime/proc.c
+++ b/src/runtime/proc.c
@@ -548,7 +548,8 @@
gp->status = Grunning;
if(debug > 1) {
lock(&debuglock);
- printf("m%d run g%d\n", m->id, gp->goid);
+ printf("m%d run g%d at %p\n", m->id, gp->goid, gp->sched.PC);
+ traceback(gp->sched.PC, gp->sched.SP+8, gp);
unlock(&debuglock);
}
m->curg = gp;
@@ -598,9 +599,8 @@
notewakeup(&sched.stopped);
}
unlock(&sched);
- // leave SP around for gc; poison PC to make sure it's not used
- g->sched.SP = (byte*)&callerpc;
- g->sched.PC = (byte*)0xdeadbeef;
+ // leave SP around for gc and traceback
+ gosave(&g->sched);
}
// The goroutine g exited its system call.
