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提交 4e6609e5 创建 作者: Nickolai Zeldovich's avatar Nickolai Zeldovich
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no memory allocation in gc.cc, but a bug somewhere

上级 7ff543f9
隐藏空白字符变更
内嵌 并排
正在显示 包含 140 行增加 和 140 行删除
bio.cc
浏览文件 @ 4e6609e5
......@@ -104,7 +104,7 @@ bget(u32 dev, u64 sector, int *writer)
bufns->remove(mkpair(victim->dev, victim->sector), &victim);
release(&victim->lock);
destroylock(&victim->lock);
gc_delayed(victim, kmfree);
gc_delayed(victim);
b = (buf*) kmalloc(sizeof(*b));
b->dev = dev;
......@@ -117,7 +117,7 @@ bget(u32 dev, u64 sector, int *writer)
gc_begin_epoch();
if (bufns->insert(mkpair(b->dev, b->sector), b) < 0) {
destroylock(&b->lock);
gc_delayed(b, kmfree);
gc_delayed(b);
goto loop;
}
// rcu_end_read() happens in brelse
......
buf.hh
浏览文件 @ 4e6609e5
struct buf {
#include "gc.hh"
struct buf : public rcu_freed {
int flags;
u32 dev;
u64 sector;
......
crange.cc
浏览文件 @ 4e6609e5
......@@ -9,6 +9,8 @@ extern "C" {
#include "cpu.h"
}
#include "gc.hh"
//
// Concurrent atomic range operations using skip lists. An insert may split an
// existing range in several ranges. A delete may remove a sequence of ranges
......@@ -54,6 +56,17 @@ extern "C" {
enum { crange_debug = 0 };
enum { crange_checking = 0 };
struct range {
u64 key;
u64 size;
void *value;
int curlevel; // the current levels it appears on
int nlevel; // the number of levels this range should appear
struct crange *cr; // the crange this range is part of
struct range** next; // one next pointer per level
struct spinlock *lock; // on separate cache line?
} __mpalign__;
struct crange {
int nlevel; // number of levels in the crange skip list
struct range crange_head; // a crange skip list starts with a sentinel range (key 0, sz 0)
......@@ -108,6 +121,17 @@ range_free(void *p)
kmalignfree(e);
}
class range_delayed : public rcu_freed {
private:
struct range *_e;
public:
range_delayed(range *e) : _e(e) {}
virtual ~range_delayed() {
range_free(_e);
}
};
static void
range_free_delayed(struct range *e)
{
......@@ -115,7 +139,9 @@ range_free_delayed(struct range *e)
cprintf("%d: range_free_delayed: 0x%lx 0x%lx-0x%lx(%lu) %lu\n", myproc()->pid, (long) e, e->key, e->key + (e)->size, e->size, myproc()->epoch);
crange_check(e->cr, e);
assert(e->curlevel == -1);
gc_delayed(e, range_free);
range_delayed *rd = new range_delayed(e);
gc_delayed(rd);
}
static void
......
file.hh
浏览文件 @ 4e6609e5
#include "cpputil.hh"
#include "ns.hh"
#include "gc.hh"
u64 namehash(const strbuf<DIRSIZ>&);
......@@ -18,7 +19,7 @@ struct file {
// in-core file system types
struct inode {
struct inode : public rcu_freed {
u32 dev; // Device number
u32 inum; // Inode number
u32 gen; // Generation number
......@@ -36,6 +37,9 @@ struct inode {
short nlink;
u32 size;
u32 addrs[NDIRECT+1];
inode();
virtual ~inode();
};
#define I_BUSYR 0x1
......
fs.cc
浏览文件 @ 4e6609e5
......@@ -220,20 +220,21 @@ iupdate(struct inode *ip)
// But it has a ref count, so it won't be freed or reused.
// Though unlocked, all fields will be present,
// so looking a ip->inum and ip->gen are OK even w/o lock.
static void
ifree(void *arg)
inode::inode()
{
struct inode *ip = (inode*) arg;
dir = 0;
}
if (ip->dir) {
ip->dir->remove(strbuf<DIRSIZ>("."));
ip->dir->remove(strbuf<DIRSIZ>(".."));
gc_delayed(ip->dir, del_rcu_freed);
ip->dir = 0;
inode::~inode()
{
if (dir) {
dir->remove(strbuf<DIRSIZ>("."));
dir->remove(strbuf<DIRSIZ>(".."));
gc_delayed(dir);
dir = 0;
}
destroylock(&ip->lock);
kmfree(ip);
destroylock(&lock);
}
struct inode*
......@@ -295,13 +296,13 @@ iget(u32 dev, u32 inum)
}
release(&victim->lock);
ins->remove(mkpair(victim->dev, victim->inum), &victim);
gc_delayed(victim, ifree);
gc_delayed(victim);
} else {
if (!__sync_bool_compare_and_swap(&icache_free[mycpu()->id].x, cur_free, cur_free-1))
goto retry_evict;
}
ip = (inode*) kmalloc(sizeof(*ip));
ip = new inode();
ip->dev = dev;
ip->inum = inum;
ip->ref = 1;
......@@ -310,10 +311,8 @@ iget(u32 dev, u32 inum)
snprintf(ip->lockname, sizeof(ip->lockname), "cv:ino:%d", ip->inum);
initlock(&ip->lock, ip->lockname+3, LOCKSTAT_FS);
initcondvar(&ip->cv, ip->lockname);
ip->dir = 0;
if (ins->insert(mkpair(ip->dev, ip->inum), ip) < 0) {
destroylock(&ip->lock);
gc_delayed(ip, kmfree);
gc_delayed(ip);
goto retry;
}
......@@ -419,7 +418,7 @@ iput(struct inode *ip)
iupdate(ip);
ins->remove(mkpair(ip->dev, ip->inum), &ip);
gc_delayed(ip, ifree);
gc_delayed(ip);
__sync_fetch_and_add(&icache_free[mycpu()->id].x, 1);
return;
}
......@@ -478,6 +477,18 @@ bmap(struct inode *ip, u32 bn)
// Truncate inode (discard contents).
// Only called after the last dirent referring
// to this inode has been erased on disk.
class diskblock : public rcu_freed {
private:
int _dev;
u64 _block;
public:
diskblock(int dev, u64 block) : _dev(dev), _block(block) {}
virtual ~diskblock() {
bfree(_dev, _block);
}
};
static void
itrunc(struct inode *ip)
{
......@@ -487,7 +498,8 @@ itrunc(struct inode *ip)
for(i = 0; i < NDIRECT; i++){
if(ip->addrs[i]){
gc_delayed2(ip->dev, ip->addrs[i], bfree);
diskblock *db = new diskblock(ip->dev, ip->addrs[i]);
gc_delayed(db);
ip->addrs[i] = 0;
}
}
......@@ -496,11 +508,15 @@ itrunc(struct inode *ip)
bp = bread(ip->dev, ip->addrs[NDIRECT], 0);
a = (u32*)bp->data;
for(j = 0; j < NINDIRECT; j++){
if(a[j])
gc_delayed2(ip->dev, a[j], bfree);
if(a[j]) {
diskblock *db = new diskblock(ip->dev, a[j]);
gc_delayed(db);
}
}
brelse(bp, 0);
gc_delayed2(ip->dev, ip->addrs[NDIRECT], bfree);
diskblock *db = new diskblock(ip->dev, ip->addrs[NDIRECT]);
gc_delayed(db);
ip->addrs[NDIRECT] = 0;
}
......
gc.cc
浏览文件 @ 4e6609e5
......@@ -32,28 +32,15 @@ enum { gc_debug = 0 };
#define NGC 10000
struct gc {
struct headinfo {
rcu_freed *head;
u64 epoch;
struct gc *next;
union {
struct {
void (*dofree)(void *);
void *item;
} f1;
struct {
void (*dofree)(int, u64);
int arg1;
u64 arg2;
} f2;
};
int type;
} __mpalign__;
};
static struct gc_state {
struct condvar cv;
struct gc delayed[NEPOCH];
struct gc tofree[NEPOCH];
headinfo delayed[NEPOCH];
headinfo tofree[NEPOCH];
int ndelayed;
int min_epoch;
int nrun;
......@@ -64,44 +51,21 @@ static struct gc_state {
static struct { struct spinlock l __mpalign__; } gc_lock;
u64 global_epoch __mpalign__;
struct gc *
gc_alloc()
{
struct gc *r = (gc*) kmalloc(sizeof(struct gc));
assert(r);
__sync_fetch_and_add(&gc_state[mycpu()->id].ndelayed, 1);
return r;
}
static void
gc_free_elem(struct gc *r)
{
switch (r->type) {
case 1:
r->f1.dofree(r->f1.item);
break;
case 2:
r->f2.dofree(r->f2.arg1, r->f2.arg2);
break;
default:
panic("rcu type");
}
kmfree(r);
}
static int
gc_free_tofreelist(struct gc **head, u64 epoch)
gc_free_tofreelist(rcu_freed **head, u64 epoch)
{
int nfree = 0;
struct gc *r, *nr;
rcu_freed *r, *nr;
for (r = *head; r != NULL; r = nr) {
if (r->epoch > epoch) {
cprintf("gc_free_tofreelist: r->epoch %ld > epoch %ld\n", r->epoch, epoch);
if (r->_rcu_epoch > epoch) {
cprintf("gc_free_tofreelist: r->epoch %ld > epoch %ld\n", r->_rcu_epoch, epoch);
assert(0);
}
nr = r->next;
gc_free_elem(r);
nr = r->_rcu_next;
cprintf("about to delete %p\n", r);
delete r;
cprintf("delete done\n");
nfree++;
}
*head = r;
......@@ -113,13 +77,13 @@ gc_free_tofreelist(struct gc **head, u64 epoch)
void *
gc_move_to_tofree_cpu(int c, u64 epoch)
{
struct gc *head;
rcu_freed *head;
u32 fe = (epoch - (NEPOCH-2)) % NEPOCH;
int cas;
assert(gc_state[c].delayed[fe].epoch == epoch-(NEPOCH-2)); // XXX race with setting epoch = 0
// unhook list for fe epoch atomically; this shouldn't fail
head = gc_state[c].delayed[fe].next;
cas = __sync_bool_compare_and_swap(&(gc_state[c].delayed[fe].next), head, 0);
head = gc_state[c].delayed[fe].head;
cas = __sync_bool_compare_and_swap(&(gc_state[c].delayed[fe].head), head, 0);
assert(cas);
// insert list into tofree list so that each core can free in parallel and free its elements
......@@ -128,12 +92,12 @@ gc_move_to_tofree_cpu(int c, u64 epoch)
gc_state[c].delayed[fe].epoch);
assert(0);
}
cas = __sync_bool_compare_and_swap(&(gc_state[c].tofree[fe].next), 0, head);
cas = __sync_bool_compare_and_swap(&(gc_state[c].tofree[fe].head), 0, head);
assert(cas);
// move delayed NEPOCH's adhead
gc_state[c].delayed[fe].epoch += NEPOCH;
assert(gc_state[c].delayed[fe].next == 0);
assert(gc_state[c].delayed[fe].head == 0);
return 0;
}
......@@ -191,9 +155,10 @@ gc_delayfreelist(void)
release(&gc_lock.l);
}
static void
gc_delayed_int(struct gc *r)
void
gc_delayed(rcu_freed *e)
{
__sync_fetch_and_add(&gc_state[mycpu()->id].ndelayed, 1);
pushcli();
int c = mycpu()->id;
u64 myepoch = myproc()->epoch;
......@@ -204,39 +169,14 @@ gc_delayed_int(struct gc *r)
cprintf("%d: myepoch %lu minepoch %lu\n", myproc()->pid, myepoch, minepoch);
panic("gc_delayed_int");
}
r->epoch = myepoch;
e->_rcu_epoch = myepoch;
do {
r->next = gc_state[c].delayed[myepoch % NEPOCH].next;
} while (!__sync_bool_compare_and_swap(&(gc_state[c].delayed[myepoch % NEPOCH].next), r->next, r));
e->_rcu_next = gc_state[c].delayed[myepoch % NEPOCH].head;
} while (!__sync_bool_compare_and_swap(&(gc_state[c].delayed[myepoch % NEPOCH].head), e->_rcu_next, e));
popcli();
}
void
gc_delayed(void *e, void (*dofree)(void *))
{
struct gc *r = gc_alloc();
if (r == 0)
panic("gc_delayed");
r->f1.dofree = dofree;
r->f1.item = e;
r->type = 1;
gc_delayed_int(r);
}
void
gc_delayed2(int a1, u64 a2, void (*dofree)(int,u64))
{
struct gc *r = gc_alloc();
if (r == 0)
panic("gc_delayed2");
r->f2.dofree = dofree;
r->f2.arg1 = a1;
r->f2.arg2 = a2;
r->type = 2;
gc_delayed_int(r);
}
void
gc_begin_epoch(void)
{
if (myproc() == NULL) return;
......@@ -286,7 +226,7 @@ gc_worker(void *x)
u64 global = global_epoch;
myproc()->epoch = global_epoch; // move the gc thread to next epoch
for (i = gc_state[mycpu()->id].min_epoch; i < global-2; i++) {
int nfree = gc_free_tofreelist(&(gc_state[mycpu()->id].tofree[i%NEPOCH].next), i);
int nfree = gc_free_tofreelist(&(gc_state[mycpu()->id].tofree[i%NEPOCH].head), i);
gc_state[mycpu()->id].tofree[i%NEPOCH].epoch += NEPOCH;
__sync_fetch_and_sub(&gc_state[mycpu()->id].ndelayed, nfree);
if (0 && nfree > 0) {
......@@ -337,10 +277,3 @@ initgc(void)
release(&gcp->lock);
}
}
void
del_rcu_freed(void *arg)
{
rcu_freed *rf = (rcu_freed*) arg;
delete rf;
}
gc.hh
浏览文件 @ 4e6609e5
#pragma once
class rcu_freed {
private:
public:
u64 _rcu_epoch;
rcu_freed *_rcu_next;
public:
virtual ~rcu_freed() {}
};
void del_rcu_freed(void*);
} __mpalign__;
kernel.h
浏览文件 @ 4e6609e5
......@@ -56,17 +56,7 @@ void consoleintr(int(*)(void));
#define assert(c) if (!(c)) { cprintf("%s:%d: ", __FILE__, __LINE__); panic("assertion failure"); }
// crange.c
struct range {
u64 key;
u64 size;
void *value;
int curlevel; // the current levels it appears on
int nlevel; // the number of levels this range should appear
struct crange *cr; // the crange this range is part of
struct range** next; // one next pointer per level
struct spinlock *lock; // on separate cache line?
} __mpalign__;
struct range;
struct crange* crange_alloc(int nlevel);
void crange_free(struct crange *cr);
......@@ -120,10 +110,13 @@ void initgc(void);
void initprocgc(struct proc *);
void gc_begin_epoch();
void gc_end_epoch();
void gc_delayed(void*, void (*dofree)(void*));
void gc_delayed2(int, u64, void (*dofree)(int, u64));
void gc_start(void);
#ifdef __cplusplus
class rcu_freed;
void gc_delayed(rcu_freed *);
#endif
// hwvm.c
void freevm(pml4e_t*);
pml4e_t* setupkvm(void);
......
ns.hh
浏览文件 @ 4e6609e5
......@@ -76,7 +76,7 @@ class xns : public rcu_freed {
if (!allowdup) {
for (auto x = root; x; x = x->next) {
if (x->key == key) {
gc_delayed(e, del_rcu_freed);
gc_delayed(e);
return -1;
}
}
......@@ -131,7 +131,7 @@ class xns : public rcu_freed {
}
*pelock = 0;
gc_delayed(e, del_rcu_freed);
gc_delayed(e);
return true;
}
......
proc.cc
浏览文件 @ 4e6609e5
......@@ -179,11 +179,24 @@ exit(void)
panic("zombie exit");
}
class delayedfree : public rcu_freed {
private:
proc *_p;
public:
delayedfree(proc *p) : _p(p) {}
virtual ~delayedfree() {
kmfree(_p);
}
};
static void
freeproc(struct proc *p)
{
destroylock(&p->lock);
gc_delayed(p, kmfree);
delayedfree *df = new delayedfree(p);
gc_delayed(df);
}
// Look in the process table for an UNUSED proc.
......
vm.cc
浏览文件 @ 4e6609e5
......@@ -13,6 +13,8 @@ extern "C" {
#include "vm.h"
}
#include "gc.hh"
static void vmap_free(void *p);
enum { vm_debug = 0 };
......@@ -47,6 +49,17 @@ vma_free(void *p)
kmfree(e);
}
class vma_delayed : public rcu_freed {
private:
vma *_e;
public:
vma_delayed(vma *e) : _e(e) {}
virtual ~vma_delayed() {
vma_free(_e);
}
};
static int
vmn_doallocpg(struct vmnode *n)
{
......@@ -469,7 +482,9 @@ vmap_remove(struct vmap *m, uptr va_start, u64 len)
return -1;
}
crange_del(m->cr, va_start, len);
gc_delayed(e, vma_free);
vma_delayed *vd = new vma_delayed(e);
gc_delayed(vd);
release(&m->lock);
return 0;
}
......@@ -601,7 +616,8 @@ vmap_remove(struct vmap *m, uptr va_start, u64 len)
cprintf("vmap_remove: partial unmap unsupported\n");
return -1;
}
gc_delayed(m->e[i], vma_free);
vma_delayed *vd = new vma_delayed(m->e[i]);
gc_delayed(vd);
m->e[i] = 0;
}
}
......
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