ref: ac98922f44c3df8839f1bdd07f23fcccf27d0cba
dir: /sys/src/cmd/venti/srv/sortientry.c/
#include "stdinc.h"
#include "dat.h"
#include "fns.h"
#include <bio.h>
typedef struct IEBuck IEBuck;
typedef struct IEBucks IEBucks;
enum
{
ClumpChunks = 32*1024
};
struct IEBuck
{
u32int head; /* head of chain of chunks on the disk */
u32int used; /* usage of the last chunk */
u64int total; /* total number of bytes in this bucket */
u8int *buf; /* chunk of entries for this bucket */
};
struct IEBucks
{
Part *part;
u64int off; /* offset for writing data in the partition */
u32int chunks; /* total chunks written to fd */
u64int max; /* max bytes entered in any one bucket */
int bits; /* number of bits in initial bucket sort */
int nbucks; /* 1 << bits, the number of buckets */
u32int size; /* bytes in each of the buckets chunks */
u32int usable; /* amount usable for IEntry data */
u8int *buf; /* buffer for all chunks */
u8int *xbuf;
IEBuck *bucks;
};
#define U32GET(p) (((p)[0]<<24)|((p)[1]<<16)|((p)[2]<<8)|(p)[3])
#define U32PUT(p,v) (p)[0]=(v)>>24;(p)[1]=(v)>>16;(p)[2]=(v)>>8;(p)[3]=(v)
static IEBucks *initiebucks(Part *part, int bits, u32int size);
static int flushiebuck(IEBucks *ib, int b, int reset);
static int flushiebucks(IEBucks *ib);
static u32int sortiebuck(IEBucks *ib, int b);
static u64int sortiebucks(IEBucks *ib);
static int sprayientry(IEBucks *ib, IEntry *ie);
static u32int readarenainfo(IEBucks *ib, Arena *arena, u64int a, Bloom *b);
static u32int readiebuck(IEBucks *ib, int b);
static void freeiebucks(IEBucks *ib);
/*
* build a sorted file with all IEntries which should be in ix.
* assumes the arenas' directories are up to date.
* reads each, converts the entries to index entries,
* and sorts them.
*/
u64int
sortrawientries(Index *ix, Part *tmp, u64int *base, Bloom *bloom)
{
IEBucks *ib;
u64int clumps, sorted;
u32int n;
int i, ok;
/* ZZZ should allow configuration of bits, bucket size */
ib = initiebucks(tmp, 8, 64*1024);
if(ib == nil){
seterr(EOk, "can't create sorting buckets: %r");
return TWID64;
}
ok = 0;
clumps = 0;
fprint(2, "constructing entry list\n");
for(i = 0; i < ix->narenas; i++){
n = readarenainfo(ib, ix->arenas[i], ix->amap[i].start, bloom);
if(n == TWID32){
ok = -1;
break;
}
clumps += n;
}
fprint(2, "sorting %lld entries\n", clumps);
if(ok == 0){
sorted = sortiebucks(ib);
*base = (u64int)ib->chunks * ib->size;
if(sorted != clumps){
fprint(2, "sorting messed up: clumps=%lld sorted=%lld\n", clumps, sorted);
ok = -1;
}
}
freeiebucks(ib);
if(ok < 0)
return TWID64;
return clumps;
}
#define CHECK(cis) if(((ulong*)cis)[-4] != 0xA110C09) xabort();
void
xabort(void)
{
int *x;
x = 0;
*x = 0;
}
/*
* read in all of the arena's clump directory,
* convert to IEntry format, and bucket sort based
* on the first few bits.
*/
static u32int
readarenainfo(IEBucks *ib, Arena *arena, u64int a, Bloom *b)
{
IEntry ie;
ClumpInfo *ci, *cis;
u32int clump;
int i, n, ok, nskip;
if(arena->memstats.clumps)
fprint(2, "\tarena %s: %d entries\n", arena->name, arena->memstats.clumps);
else
fprint(2, "[%s] ", arena->name);
cis = MKN(ClumpInfo, ClumpChunks);
ok = 0;
nskip = 0;
memset(&ie, 0, sizeof(IEntry));
for(clump = 0; clump < arena->memstats.clumps; clump += n){
n = ClumpChunks;
if(n > arena->memstats.clumps - clump)
n = arena->memstats.clumps - clump;
if(readclumpinfos(arena, clump, cis, n) != n){
seterr(EOk, "arena directory read failed: %r");
ok = -1;
break;
}
for(i = 0; i < n; i++){
ci = &cis[i];
ie.ia.type = ci->type;
ie.ia.size = ci->uncsize;
ie.ia.addr = a;
a += ci->size + ClumpSize;
ie.ia.blocks = (ci->size + ClumpSize + (1 << ABlockLog) - 1) >> ABlockLog;
scorecp(ie.score, ci->score);
if(ci->type == VtCorruptType){
if(0) print("! %V %22lld %3d %5d %3d\n",
ie.score, ie.ia.addr, ie.ia.type, ie.ia.size, ie.ia.blocks);
nskip++;
}else
sprayientry(ib, &ie);
markbloomfilter(b, ie.score);
}
}
free(cis);
if(ok < 0)
return TWID32;
return clump - nskip;
}
/*
* initialize the external bucket sorting data structures
*/
static IEBucks*
initiebucks(Part *part, int bits, u32int size)
{
IEBucks *ib;
int i;
ib = MKZ(IEBucks);
if(ib == nil){
seterr(EOk, "out of memory");
return nil;
}
ib->bits = bits;
ib->nbucks = 1 << bits;
ib->size = size;
ib->usable = (size - U32Size) / IEntrySize * IEntrySize;
ib->bucks = MKNZ(IEBuck, ib->nbucks);
if(ib->bucks == nil){
seterr(EOk, "out of memory allocation sorting buckets");
freeiebucks(ib);
return nil;
}
ib->xbuf = MKN(u8int, size * ((1 << bits)+1));
ib->buf = (u8int*)(((uintptr)ib->xbuf+size-1)&~(uintptr)(size-1));
if(ib->buf == nil){
seterr(EOk, "out of memory allocating sorting buckets' buffers");
freeiebucks(ib);
return nil;
}
for(i = 0; i < ib->nbucks; i++){
ib->bucks[i].head = TWID32;
ib->bucks[i].buf = &ib->buf[i * size];
}
ib->part = part;
return ib;
}
static void
freeiebucks(IEBucks *ib)
{
if(ib == nil)
return;
free(ib->bucks);
free(ib->buf);
free(ib);
}
/*
* initial sort: put the entry into the correct bucket
*/
static int
sprayientry(IEBucks *ib, IEntry *ie)
{
u32int n;
int b;
b = hashbits(ie->score, ib->bits);
n = ib->bucks[b].used;
if(n + IEntrySize > ib->usable){
/* should be flushed below, but if flush fails, this can happen */
seterr(EOk, "out of space in bucket");
return -1;
}
packientry(ie, &ib->bucks[b].buf[n]);
n += IEntrySize;
ib->bucks[b].used = n;
if(n + IEntrySize <= ib->usable)
return 0;
return flushiebuck(ib, b, 1);
}
/*
* finish sorting:
* for each bucket, read it in and sort it
* write out the the final file
*/
static u64int
sortiebucks(IEBucks *ib)
{
u64int tot;
u32int n;
int i;
if(flushiebucks(ib) < 0)
return TWID64;
for(i = 0; i < ib->nbucks; i++)
ib->bucks[i].buf = nil;
ib->off = (u64int)ib->chunks * ib->size;
free(ib->xbuf);
ib->buf = MKN(u8int, ib->max + U32Size);
if(ib->buf == nil){
seterr(EOk, "out of memory allocating final sorting buffer; try more buckets");
return TWID64;
}
tot = 0;
for(i = 0; i < ib->nbucks; i++){
n = sortiebuck(ib, i);
if(n == TWID32)
return TWID64;
if(n != ib->bucks[i].total/IEntrySize)
fprint(2, "bucket %d changed count %d => %d\n",
i, (int)(ib->bucks[i].total/IEntrySize), n);
tot += n;
}
return tot;
}
/*
* sort from bucket b of ib into the output file to
*/
static u32int
sortiebuck(IEBucks *ib, int b)
{
u32int n;
n = readiebuck(ib, b);
if(n == TWID32)
return TWID32;
qsort(ib->buf, n, IEntrySize, ientrycmp);
if(writepart(ib->part, ib->off, ib->buf, n*IEntrySize) < 0){
seterr(EOk, "can't write sorted bucket: %r");
return TWID32;
}
ib->off += n * IEntrySize;
return n;
}
/*
* write out a single bucket
*/
static int
flushiebuck(IEBucks *ib, int b, int reset)
{
u32int n;
if(ib->bucks[b].used == 0)
return 0;
n = ib->bucks[b].used;
U32PUT(&ib->bucks[b].buf[n], ib->bucks[b].head);
n += U32Size;
USED(n);
if(writepart(ib->part, (u64int)ib->chunks * ib->size, ib->bucks[b].buf, ib->size) < 0){
seterr(EOk, "can't write sorting bucket to file: %r");
xabort();
return -1;
}
ib->bucks[b].head = ib->chunks++;
ib->bucks[b].total += ib->bucks[b].used;
if(reset)
ib->bucks[b].used = 0;
return 0;
}
/*
* write out all of the buckets, and compute
* the maximum size of any bucket
*/
static int
flushiebucks(IEBucks *ib)
{
int i;
for(i = 0; i < ib->nbucks; i++){
if(flushiebuck(ib, i, 0) < 0)
return -1;
if(ib->bucks[i].total > ib->max)
ib->max = ib->bucks[i].total;
}
return 0;
}
/*
* read in the chained buffers for bucket b,
* and return it's total number of IEntries
*/
static u32int
readiebuck(IEBucks *ib, int b)
{
u32int head, m, n;
head = ib->bucks[b].head;
n = 0;
m = ib->bucks[b].used;
if(m == 0)
m = ib->usable;
if(0) if(ib->bucks[b].total)
fprint(2, "\tbucket %d: %lld entries\n", b, ib->bucks[b].total/IEntrySize);
while(head != TWID32){
if(readpart(ib->part, (u64int)head * ib->size, &ib->buf[n], m+U32Size) < 0){
seterr(EOk, "can't read index sort bucket: %r");
return TWID32;
}
n += m;
head = U32GET(&ib->buf[n]);
m = ib->usable;
}
if(n != ib->bucks[b].total)
fprint(2, "\tbucket %d: expected %d entries, got %d\n",
b, (int)ib->bucks[b].total/IEntrySize, n/IEntrySize);
return n / IEntrySize;
}