ref: 88ccea37f65b87312292b2b1a107c39927c6a2c3
dir: /sys/src/cmd/venti/srv/icachewrite.c/
/*
* Write the dirty icache entries to disk. Random seeks are
* so expensive that it makes sense to wait until we have
* a lot and then just make a sequential pass over the disk.
*/
#include "stdinc.h"
#include "dat.h"
#include "fns.h"
static void icachewriteproc(void*);
static void icachewritecoord(void*);
static IEntry *iesort(IEntry*);
int icachesleeptime = 1000; /* milliseconds */
int minicachesleeptime = 0;
enum
{
Bufsize = 8*1024*1024
};
typedef struct IWrite IWrite;
struct IWrite
{
Round round;
AState as;
};
static IWrite iwrite;
void
initicachewrite(void)
{
int i;
Index *ix;
initround(&iwrite.round, "icache", 120*60*1000);
ix = mainindex;
for(i=0; i<ix->nsects; i++){
ix->sects[i]->writechan = chancreate(sizeof(ulong), 1);
ix->sects[i]->writedonechan = chancreate(sizeof(ulong), 1);
vtproc(icachewriteproc, ix->sects[i]);
}
vtproc(icachewritecoord, nil);
vtproc(delaykickroundproc, &iwrite.round);
}
static u64int
ie2diskaddr(Index *ix, ISect *is, IEntry *ie)
{
u64int bucket, addr;
bucket = hashbits(ie->score, 32)/ix->div;
addr = is->blockbase + ((bucket - is->start) << is->blocklog);
return addr;
}
static IEntry*
nextchunk(Index *ix, ISect *is, IEntry **pie, u64int *paddr, uint *pnbuf)
{
u64int addr, naddr;
uint nbuf;
int bsize;
IEntry *iefirst, *ie, **l;
bsize = 1<<is->blocklog;
iefirst = *pie;
addr = ie2diskaddr(ix, is, iefirst);
nbuf = 0;
for(l = &iefirst->nextdirty; (ie = *l) != nil; l = &(*l)->nextdirty){
naddr = ie2diskaddr(ix, is, ie);
if(naddr - addr >= Bufsize)
break;
nbuf = naddr - addr;
}
nbuf += bsize;
*l = nil;
*pie = ie;
*paddr = addr;
*pnbuf = nbuf;
return iefirst;
}
static int
icachewritesect(Index *ix, ISect *is, u8int *buf)
{
int err, i, werr, h, bsize, t;
u32int lo, hi;
u64int addr, naddr;
uint nbuf, off;
DBlock *b;
IBucket ib;
IEntry *ie, *iedirty, **l, *chunk;
lo = is->start * ix->div;
if(TWID32/ix->div < is->stop)
hi = TWID32;
else
hi = is->stop * ix->div - 1;
trace(TraceProc, "icachewritesect enter %ud %ud %llud",
lo, hi, iwrite.as.aa);
iedirty = icachedirty(lo, hi, iwrite.as.aa);
iedirty = iesort(iedirty);
bsize = 1 << is->blocklog;
err = 0;
while(iedirty){
disksched();
while((t = icachesleeptime) == SleepForever){
sleep(1000);
disksched();
}
if(t < minicachesleeptime)
t = minicachesleeptime;
if(t > 0)
sleep(t);
trace(TraceProc, "icachewritesect nextchunk");
chunk = nextchunk(ix, is, &iedirty, &addr, &nbuf);
trace(TraceProc, "icachewritesect readpart 0x%llux+0x%ux",
addr, nbuf);
if(readpart(is->part, addr, buf, nbuf) < 0){
fprint(2, "%s: part %s addr 0x%llux: icachewritesect "
"readpart: %r\n", argv0, is->part->name, addr);
err = -1;
continue;
}
trace(TraceProc, "icachewritesect updatebuf");
addstat(StatIsectReadBytes, nbuf);
addstat(StatIsectRead, 1);
for(l=&chunk; (ie=*l)!=nil; l=&ie->nextdirty){
again:
naddr = ie2diskaddr(ix, is, ie);
off = naddr - addr;
if(off+bsize > nbuf){
fprint(2, "%s: whoops! addr=0x%llux nbuf=%ud "
"addr+nbuf=0x%llux naddr=0x%llux\n",
argv0, addr, nbuf, addr+nbuf, naddr);
assert(off+bsize <= nbuf);
}
unpackibucket(&ib, buf+off, is->bucketmagic);
if(okibucket(&ib, is) < 0){
fprint(2, "%s: bad bucket XXX\n", argv0);
goto skipit;
}
trace(TraceProc, "icachewritesect add %V at 0x%llux",
ie->score, naddr);
h = bucklook(ie->score, ie->ia.type, ib.data, ib.n);
if(h & 1){
h ^= 1;
packientry(ie, &ib.data[h]);
}else if(ib.n < is->buckmax){
memmove(&ib.data[h + IEntrySize], &ib.data[h],
ib.n*IEntrySize - h);
ib.n++;
packientry(ie, &ib.data[h]);
}else{
fprint(2, "%s: bucket overflow XXX\n", argv0);
skipit:
err = -1;
*l = ie->nextdirty;
ie = *l;
if(ie)
goto again;
else
break;
}
packibucket(&ib, buf+off, is->bucketmagic);
}
diskaccess(1);
trace(TraceProc, "icachewritesect writepart", addr, nbuf);
werr = 0;
if(writepart(is->part, addr, buf, nbuf) < 0 || flushpart(is->part) < 0)
werr = -1;
for(i=0; i<nbuf; i+=bsize){
if((b = _getdblock(is->part, addr+i, ORDWR, 0)) != nil){
memmove(b->data, buf+i, bsize);
putdblock(b);
}
}
if(werr < 0){
fprint(2, "%s: part %s addr 0x%llux: icachewritesect "
"writepart: %r\n", argv0, is->part->name, addr);
err = -1;
continue;
}
addstat(StatIsectWriteBytes, nbuf);
addstat(StatIsectWrite, 1);
icacheclean(chunk);
}
trace(TraceProc, "icachewritesect done");
return err;
}
static void
icachewriteproc(void *v)
{
int ret;
uint bsize;
ISect *is;
Index *ix;
u8int *buf;
ix = mainindex;
is = v;
threadsetname("icachewriteproc:%s", is->part->name);
bsize = 1<<is->blocklog;
buf = emalloc(Bufsize+bsize);
buf = (u8int*)(((uintptr)buf+bsize-1)&~(uintptr)(bsize-1));
for(;;){
trace(TraceProc, "icachewriteproc recv");
recv(is->writechan, 0);
trace(TraceWork, "start");
ret = icachewritesect(ix, is, buf);
trace(TraceProc, "icachewriteproc send");
trace(TraceWork, "finish");
sendul(is->writedonechan, ret);
}
}
static void
icachewritecoord(void *v)
{
int i, err;
Index *ix;
AState as;
USED(v);
threadsetname("icachewritecoord");
ix = mainindex;
iwrite.as = icachestate();
for(;;){
trace(TraceProc, "icachewritecoord sleep");
waitforkick(&iwrite.round);
trace(TraceWork, "start");
as = icachestate();
if(as.arena==iwrite.as.arena && as.aa==iwrite.as.aa){
/* will not be able to do anything more than last flush - kick disk */
trace(TraceProc, "icachewritecoord kick dcache");
kickdcache();
trace(TraceProc, "icachewritecoord kicked dcache");
goto SkipWork; /* won't do anything; don't bother rewriting bloom filter */
}
iwrite.as = as;
trace(TraceProc, "icachewritecoord start flush");
if(iwrite.as.arena){
for(i=0; i<ix->nsects; i++)
send(ix->sects[i]->writechan, 0);
if(ix->bloom)
send(ix->bloom->writechan, 0);
err = 0;
for(i=0; i<ix->nsects; i++)
err |= recvul(ix->sects[i]->writedonechan);
if(ix->bloom)
err |= recvul(ix->bloom->writedonechan);
trace(TraceProc, "icachewritecoord donewrite err=%d", err);
if(err == 0){
setatailstate(&iwrite.as);
}
}
SkipWork:
icacheclean(nil); /* wake up anyone waiting */
trace(TraceWork, "finish");
addstat(StatIcacheFlush, 1);
}
}
void
flushicache(void)
{
trace(TraceProc, "flushicache enter");
kickround(&iwrite.round, 1);
trace(TraceProc, "flushicache exit");
}
void
kickicache(void)
{
kickround(&iwrite.round, 0);
}
void
delaykickicache(void)
{
delaykickround(&iwrite.round);
}
static IEntry*
iesort(IEntry *ie)
{
int cmp;
IEntry **l;
IEntry *ie1, *ie2, *sorted;
if(ie == nil || ie->nextdirty == nil)
return ie;
/* split the lists */
ie1 = ie;
ie2 = ie;
if(ie2)
ie2 = ie2->nextdirty;
if(ie2)
ie2 = ie2->nextdirty;
while(ie1 && ie2){
ie1 = ie1->nextdirty;
ie2 = ie2->nextdirty;
if(ie2)
ie2 = ie2->nextdirty;
}
if(ie1){
ie2 = ie1->nextdirty;
ie1->nextdirty = nil;
}
/* sort the lists */
ie1 = iesort(ie);
ie2 = iesort(ie2);
/* merge the lists */
sorted = nil;
l = &sorted;
cmp = 0;
while(ie1 || ie2){
if(ie1 && ie2)
cmp = scorecmp(ie1->score, ie2->score);
if(ie1==nil || (ie2 && cmp > 0)){
*l = ie2;
l = &ie2->nextdirty;
ie2 = ie2->nextdirty;
}else{
*l = ie1;
l = &ie1->nextdirty;
ie1 = ie1->nextdirty;
}
}
*l = nil;
return sorted;
}