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NetBSD/lib/libc/db/mpool/mpool.libtp
cgd 5fb6a3660e Import of Berkeley DB version 1.85
1996-05-03 21:04:19 +00:00

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/******************************************************************************
VERSION $Id: mpool.libtp,v 1.1.1.1 1996/05/03 21:05:32 cgd Exp $
PACKAGE: User Level Shared Memory Manager
DESCRIPTION:
This package provides a buffer pool interface implemented as
a collection of file pages mapped into shared memory.
Based on Mark's buffer manager
ROUTINES:
External
buf_alloc
buf_flags
buf_get
buf_init
buf_last
buf_open
buf_pin
buf_sync
buf_unpin
Internal
bf_assign_buf
bf_fid_to_fd
bf_newbuf
bf_put_page
******************************************************************************/
#include <sys/types.h>
#include <assert.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <stdio.h>
#include <errno.h>
#include "list.h"
#include "user.h"
#include "txn_sys.h"
#include "buf.h"
#include "semkeys.h"
#include "error.h"
/*
we need to translate between some type of file id that the user
process passes and a file descriptor. For now, it's a nop.
*/
#define GET_MASTER get_sem ( buf_spinlock )
#define RELEASE_MASTER release_sem ( buf_spinlock )
#define LRUID *buf_lru
#define LRUP (bufhdr_table+*buf_lru)
#define MRU bufhdr_table[*buf_lru].lru.prev
/* Global indicator that you have started reusing buffers */
int do_statistics = 0;
/*
Process Statics (pointers into shared memory)
*/
static BUF_T *buf_table = 0;
static BUFHDR_T *bufhdr_table;
static int *buf_hash_table;
static int *buf_lru; /* LRU is the free list */
static int buf_spinlock;
static FINFO_T *buf_fids;
static int *buf_sp; /* Pointer to string free space */
static char *buf_strings;
/* Process Local FID->FD table */
static int fds[NUM_FILE_ENTRIES];
/* Static routines */
static BUFHDR_T *bf_assign_buf();
static int bf_fid_to_fd();
static BUFHDR_T *bf_newbuf();
static int bf_put_page();
/*
Return 0 on success
1 on failure
*/
extern int
buf_init ( )
{
ADDR_T buf_region;
BUFHDR_T *bhp;
int i;
int ref_count;
int *spinlockp;
/*
Initialize Process local structures
*/
for ( i = 0; i < NUM_FILE_ENTRIES; i++ ) {
fds[i] = -1;
}
buf_region = attach_region ( BUF_REGION_NAME, BUF_REGION_NUM,
BUF_REGION_SIZE, &ref_count );
if ( !buf_region ) {
return (1);
}
error_log3 ( "Buf Region: ADDR: %d ID: %d SIZE: %d\n", buf_region,
BUF_REGION_NUM, BUF_REGION_SIZE );
buf_table = (BUF_T *)buf_region;
bufhdr_table = (BUFHDR_T *)(buf_table + NUM_BUFS);
buf_hash_table = (int *)(bufhdr_table + NUM_BUFS);
buf_lru = buf_hash_table + NUMTABLE_ENTRIES;
spinlockp = buf_lru + 1;
buf_fids = (FINFO_T *)(spinlockp+1);
buf_sp = (int *)(buf_fids + NUM_FILE_ENTRIES);
buf_strings = (char *)(buf_sp + 1);
/* Create locking spinlock (gets creating holding the lock) */
buf_spinlock = create_sem ( BUF_SPIN_NAME, BUF_SPIN_NUM, ref_count <= 1 );
if ( buf_spinlock < 0 ) {
return(1);
}
if ( ref_count <= 1 ) {
*spinlockp = buf_spinlock;
/* Now initialize the buffer manager */
/* 1. Free list */
*buf_lru = 0;
/* 2. Buffer headers */
for ( i = 0, bhp = bufhdr_table; i < NUM_BUFS; bhp++, i++ ) {
bhp->lru.next = i+1;
bhp->lru.prev = i-1;
bhp->flags = 0; /* All Flags off */
bhp->refcount = 0;
bhp->wait_proc = -1; /* No sleepers */
LISTPE_INIT ( hash, bhp, i ); /* Hash chains */
}
bufhdr_table[0].lru.prev = NUM_BUFS-1;
bufhdr_table[NUM_BUFS-1].lru.next = 0;
/* 3. Hash Table */
for ( i = 0; i < NUMTABLE_ENTRIES; i++ ) {
buf_hash_table[i] = NUM_BUFS;
}
/* 4. File ID Table */
for ( i = 0; i < NUM_FILE_ENTRIES; i++ ) {
buf_fids[i].offset = -1;
buf_fids[i].npages = -1;
buf_fids[i].refcount = 0;
}
/* 5. Free String Pointer */
*buf_sp = (FILE_NAME_LEN*NUM_FILE_ENTRIES);
if (RELEASE_MASTER) {
return(1);
}
error_log0 ( "Initialized buffer region\n" );
}
return (0);
}
extern void
buf_exit()
{
int ref;
int i;
/* Flush Buffer Pool on Exit */
for ( i = 0; i < NUM_FILE_ENTRIES; i++ ) {
if ( fds[i] != -1 ) {
close ( fds[i] );
}
}
if ( buf_table ) {
detach_region ( buf_table, BUF_REGION_NUM, BUF_REGION_SIZE, &ref );
}
return;
}
/*
We need an empty buffer. Find the LRU unpinned NON-Dirty page.
*/
static BUFHDR_T *
bf_newbuf()
{
int fd;
int lruid;
int nbytes;
int ndx;
BUFHDR_T *bhp;
lruid = LRUID;
for ( bhp = LRUP;
bhp->flags & (BUF_PINNED|BUF_IO_IN_PROGRESS);
bhp = LISTP_NEXTP (bufhdr_table, lru, bhp ) ) {
if ( bhp->lru.next == lruid ) {
/* OUT OF BUFFERS */
error_log1 ( "All buffers are pinned. %s\n",
"Unable to grant buffer request" );
return(NULL);
}
}
/* BHP can be used */
if ( bhp->flags & BUF_DIRTY ) {
do_statistics = 1;
/*
MIS Check for log flushed appropriately
*/
fd = bf_fid_to_fd(bhp->id.file_id);
if ( fd == -1 ) {
error_log1 ("Invalid fid %d\n", bhp->id.file_id);
return(NULL);
}
if ( bf_put_page(fd, bhp) < 0 ) {
return(NULL);
}
}
/* Update Hash Pointers */
ndx = BUF_HASH ( bhp->id.file_id, bhp->id.obj_id );
LISTP_REMOVE(bufhdr_table, hash, bhp);
if ( buf_hash_table[ndx] == (bhp-bufhdr_table) ) {
if ( bhp->hash.next != (bhp-bufhdr_table) ) {
buf_hash_table[ndx] = bhp->hash.next;
} else {
buf_hash_table[ndx] = NUM_BUFS;
}
}
INIT_BUF(bhp);
return(bhp);
}
/*
buf_alloc
Add a page to a file and return a buffer for it.
*/
ADDR_T
buf_alloc ( fid, new_pageno )
int fid;
int *new_pageno;
{
BUFHDR_T *bhp;
int fd;
int len;
int ndx;
OBJ_T fobj;
if (GET_MASTER) {
return(NULL);
}
if ( buf_fids[fid].npages == -1 ) {
/* initialize npages field */
fd = bf_fid_to_fd ( fid );
}
assert (fid < NUM_FILE_ENTRIES);
*new_pageno = buf_fids[fid].npages;
if ( *new_pageno == -1 ) {
RELEASE_MASTER;
return ( NULL );
}
buf_fids[fid].npages++;
ndx = BUF_HASH ( fid, *new_pageno );
fobj.file_id = fid;
fobj.obj_id = *new_pageno;
bhp = bf_assign_buf ( ndx, &fobj, BF_PIN|BF_DIRTY|BF_EMPTY, &len );
if ( RELEASE_MASTER ) {
/* Memory leak */
return(NULL);
}
if ( bhp ) {
return ((ADDR_T)(buf_table+(bhp-bufhdr_table)));
} else {
return ( NULL );
}
}
/*
Buffer Flags
BF_DIRTY Mark page as dirty
BF_EMPTY Don't initialize page, just get buffer
BF_PIN Retrieve with pin
MIS
Might want to add a flag that sets an LSN for this buffer is the
DIRTY flag is set
Eventually, you may want a flag that indicates the I/O and lock
request should be shipped off together, but not for now.
*/
extern ADDR_T
buf_get ( file_id, page_id, flags, len )
int file_id;
int page_id;
u_long flags;
int *len; /* Number of bytes read into buffer */
{
BUFHDR_T *bhp;
int bufid;
int fd;
int ndx;
int next_bufid;
int stat;
OBJ_T fobj;
ndx = BUF_HASH ( file_id, page_id );
fobj.file_id = (long) file_id;
fobj.obj_id = (long) page_id;
if ( GET_MASTER ) {
return(NULL);
}
/*
This could be a for loop, but we lose speed
by making all the cases general purpose so we
optimize for the no-collision case.
*/
bufid = buf_hash_table[ndx];
if ( bufid < NUM_BUFS ) {
for ( bhp = bufhdr_table+bufid;
!OBJ_EQ (bhp->id, fobj) || !(bhp->flags & BUF_VALID);
bhp = LISTP_NEXTP ( bufhdr_table, hash, bhp ) ) {
if ( bhp->hash.next == bufid ) {
goto not_found;
}
}
/* found */
if ( flags & BF_PIN ) {
bhp->flags |= BUF_PINNED;
bhp->refcount++;
#ifdef PIN_DEBUG
fprintf(stderr, "buf_get: %X PINNED (%d)\n",
buf_table + (bhp-bufhdr_table), bhp->refcount);
#endif
}
if ( flags & BF_DIRTY ) {
bhp->flags |= BUF_DIRTY;
}
while ( bhp->flags & BUF_IO_IN_PROGRESS ) {
/* MIS -- eventually err check here */
#ifdef DEBUG
printf("About to sleep on %d (me: %d\n)\n", bhp->wait_proc,
my_txnp - txn_table);
#endif
#ifdef WAIT_STATS
buf_waits++;
#endif
stat = proc_sleep_on ( &(bhp->wait_proc), buf_spinlock );
if ( stat ) {
/* Memory leak */
return(NULL);
}
if (!( bhp->flags & BUF_IO_IN_PROGRESS) &&
(!OBJ_EQ (bhp->id, fobj) || !(bhp->flags & BUF_VALID))) {
if (RELEASE_MASTER)
return(NULL);
return(buf_get ( file_id, page_id, flags, len ));
}
}
MAKE_MRU( bhp );
*len = BUFSIZE;
} else {
not_found:
/* If you get here, the page isn't in the hash table */
bhp = bf_assign_buf ( ndx, &fobj, flags, len );
}
/* Common code between found and not found */
if ( bhp && bhp->flags & BUF_NEWPAGE ) {
*len = 0;
}
if (RELEASE_MASTER){
/* Memory leak */
return(NULL);
}
if ( bhp ) {
return ((ADDR_T)(buf_table+(bhp-bufhdr_table)));
} else {
return ( NULL );
}
}
/*
MIS - do I want to add file links to buffer pool?
*/
extern int
buf_sync ( fid, close )
int fid;
int close; /* should we dec refcount and possibly
invalidate all the buffers */
{
int i;
int fd;
int invalidate;
BUFHDR_T *bhp;
if ( (fd = bf_fid_to_fd ( fid )) < 0 ) {
return(1);
}
if (GET_MASTER) {
return(1);
}
invalidate = (buf_fids[fid].refcount == 1 && close);
if ( invalidate )
for ( bhp = bufhdr_table, i = 0; i < NUM_BUFS; bhp++, i++ ) {
if (bhp->id.file_id == fid) {
if ((bhp->flags & BF_DIRTY) && (bf_put_page( fd, bhp ) < 0)) {
return(1);
}
bhp->id.file_id = -1;
}
}
if (invalidate || close)
buf_fids[fid].refcount--;
if (RELEASE_MASTER) {
return(1);
}
return(0);
}
extern int
buf_flags ( addr, set_flags, unset_flags )
ADDR_T addr;
u_long set_flags;
u_long unset_flags;
{
int bufid;
BUFHDR_T *bhp;
#ifdef PIN_DEBUG
fprintf(stderr, "buf_flags: %X setting %s%s%s%s%s releasing %s%s%s%s%s\n",
addr,
set_flags&BUF_DIRTY ? "DIRTY " : "",
set_flags&BUF_VALID ? "VALID " : "",
set_flags&BUF_PINNED ? "PINNED " : "",
set_flags&BUF_IO_ERROR ? "IO_ERROR " : "",
set_flags&BUF_IO_IN_PROGRESS ? "IO_IN_PROG " : "",
set_flags&BUF_NEWPAGE ? "NEWPAGE " : "",
unset_flags&BUF_DIRTY ? "DIRTY " : "",
unset_flags&BUF_VALID ? "VALID " : "",
unset_flags&BUF_PINNED ? "PINNED " : "",
unset_flags&BUF_IO_ERROR ? "IO_ERROR " : "",
unset_flags&BUF_IO_IN_PROGRESS ? "IO_IN_PROG " : "",
unset_flags&BUF_NEWPAGE ? "NEWPAGE " : "" );
#endif
if (!ADDR_OK(addr)) {
error_log1 ( "buf_pin: Invalid Buffer Address %x\n", addr );
return(1);
}
bufid = ((BUF_T *)addr) - buf_table;
assert ( bufid < NUM_BUFS);
bhp = &bufhdr_table[bufid];
if (GET_MASTER) {
return(1);
}
bhp->flags |= set_flags;
if ( set_flags & BUF_PINNED ) {
bhp->refcount++;
}
if ( set_flags & BUF_DIRTY ) {
unset_flags |= BUF_NEWPAGE;
}
if ( unset_flags & BUF_PINNED ) {
bhp->refcount--;
if ( bhp->refcount ) {
/* Turn off pin bit so it doesn't get unset */
unset_flags &= ~BUF_PINNED;
}
}
bhp->flags &= ~unset_flags;
MAKE_MRU(bhp);
if (RELEASE_MASTER) {
return(1);
}
return(0);
}
/*
Take a string name and produce an fid.
returns -1 on error
MIS -- this is a potential problem -- you keep actual names
here -- what if people run from different directories?
*/
extern int
buf_name_lookup ( fname )
char *fname;
{
int i;
int fid;
int ndx;
fid = -1;
if (GET_MASTER) {
return(-1);
}
for ( i = 0; i < NUM_FILE_ENTRIES; i++ ) {
if ( buf_fids[i].offset == -1 ) {
fid = i;
} else {
if (!strcmp (fname, buf_strings+buf_fids[i].offset)) {
if (RELEASE_MASTER) {
return(-1);
}
buf_fids[i].refcount++;
return(i);
}
}
}
if ( fid == -1 ) {
error_log0 ( "No more file ID's\n" );
} else {
ndx = *buf_sp - strlen(fname) - 1;
if ( ndx < 0 ) {
error_log0 ( "Out of string space\n" );
fid = -1;
} else {
*buf_sp = ndx;
strcpy ( buf_strings+ndx, fname );
buf_fids[fid].offset = ndx;
}
buf_fids[fid].refcount = 1;
}
if (RELEASE_MASTER) {
return(-1);
}
return(fid);
}
static int
bf_fid_to_fd ( fid )
int fid;
{
struct stat sbuf;
assert ( (fid < NUM_FILE_ENTRIES) && (buf_fids[fid].offset != -1) );
if ( fds[fid] != -1 ) {
return(fds[fid]);
}
fds[fid] = open ( buf_strings+buf_fids[fid].offset, O_RDWR|O_CREAT,
0666 );
if ( fds[fid] < 0 ) {
error_log3 ( "Error Opening File %s FID: %d FD: %d. Errno = %d\n",
buf_strings+buf_fids[fid].offset, fid, fds[fid],
errno );
return(-1);
}
error_log3 ( "Opening File %s FID: %d FD: %d\n",
buf_strings+buf_fids[fid].offset, fid, fds[fid] );
if ( buf_fids[fid].npages == -1 ) {
/* Initialize the npages field */
if ( fstat ( fds[fid], &sbuf ) ) {
error_log3 ( "Error Fstating %s FID: %d. Errno = %d\n",
buf_strings+buf_fids[fid].offset, fid, errno );
} else {
buf_fids[fid].npages = ( sbuf.st_size / BUFSIZE );
}
}
return ( fds[fid] );
}
static int
bf_put_page ( fd, bhp )
int fd;
BUFHDR_T *bhp;
{
int nbytes;
assert ( (bhp-bufhdr_table) < NUM_BUFS );
if ( lseek ( fd, bhp->id.obj_id << BUFSHIFT, L_SET ) < 0 ) {
return(-1);
}
bhp->flags |= BUF_IO_IN_PROGRESS;
if (RELEASE_MASTER) {
return(-1);
}
nbytes = write(fd, buf_table[bhp-bufhdr_table], BUFSIZE);
if (GET_MASTER) {
return(-2);
}
if ( nbytes < 0 ) {
error_log1 ("Write failed with error code %d\n", errno);
return(-1);
} else if ( nbytes != BUFSIZE ) {
error_log1 ("Short write: %d bytes of %d\n", nbytes, BUFSIZE );
}
bhp->flags &= ~(BUF_DIRTY|BUF_IO_IN_PROGRESS);
return (0);
}
static BUFHDR_T *
bf_assign_buf ( ndx, obj, flags, len )
int ndx;
OBJ_T *obj;
u_long flags;
int *len; /* Number of bytes read */
{
BUFHDR_T *bhp;
int fd;
assert ( obj->file_id < NUM_FILE_ENTRIES );
bhp = bf_newbuf();
if ( !bhp ) {
return(NULL);
}
OBJ_ASSIGN ( (*obj), bhp->id );
if ( buf_hash_table[ndx] >= NUM_BUFS ) {
buf_hash_table[ndx] = bhp-bufhdr_table;
} else {
LISTPE_INSERT ( bufhdr_table, hash, bhp, buf_hash_table[ndx] );
}
bhp->flags |= BUF_VALID;
if ( flags & BF_PIN ) {
bhp->flags |= BUF_PINNED;
bhp->refcount++;
#ifdef PIN_DEBUG
fprintf(stderr, "bf_assign_buf: %X PINNED (%d)\n",
buf_table + (bhp-bufhdr_table), bhp->refcount);
#endif
}
fd = bf_fid_to_fd(obj->file_id);
if ( fd == -1 ) {
error_log1 ("Invalid fid %d\n", obj->file_id);
bhp->flags |= ~BUF_IO_ERROR;
return(NULL);
}
if ( obj->obj_id >= buf_fids[obj->file_id].npages) {
buf_fids[obj->file_id].npages = obj->obj_id+1;
*len = 0;
} else if ( flags & BF_EMPTY ) {
*len = 0;
} else {
bhp->flags |= BUF_IO_IN_PROGRESS;
if (RELEASE_MASTER) {
return(NULL);
}
if ( lseek ( fd, obj->obj_id << BUFSHIFT, L_SET ) < -1 ) {
error_log2 ("Unable to perform seek on file: %d to page %d",
obj->file_id, obj->obj_id );
bhp->flags &= ~BUF_IO_IN_PROGRESS;
bhp->flags |= ~BUF_IO_ERROR;
return(NULL);
}
*len = read(fd, buf_table[bhp-bufhdr_table], BUFSIZE);
if ( *len < 0 ) {
error_log2 ("Unable to perform read on file: %d to page %d",
obj->file_id, obj->obj_id );
bhp->flags &= ~BUF_IO_IN_PROGRESS;
bhp->flags |= ~BUF_IO_ERROR;
return(NULL);
}
if (GET_MASTER) {
return(NULL);
}
bhp->flags &= ~BUF_IO_IN_PROGRESS;
if ( bhp->wait_proc != -1 ) {
/* wake up waiter and anyone waiting on it */
#ifdef DEBUG
printf("Waking transaction %d due to completed I/O\n",
bhp->wait_proc);
#endif
proc_wake_id ( bhp->wait_proc );
bhp->wait_proc = -1;
}
MAKE_MRU(bhp);
}
if ( flags & BF_DIRTY ) {
bhp->flags |= BUF_DIRTY;
} else if ( *len < BUFSIZE ) {
bhp->flags |= BUF_NEWPAGE;
}
return ( bhp );
}
int
buf_last ( fid )
int fid;
{
int val;
if (GET_MASTER) {
return(-1);
}
assert ( fid < NUM_FILE_ENTRIES );
if ( buf_fids[fid].npages == -1 ) {
/* initialize npages field */
(void) bf_fid_to_fd ( fid );
}
val = buf_fids[fid].npages;
if ( val ) {
val--; /* Convert to page number */
}
if (RELEASE_MASTER) {
return(-1);
}
return(val);
}
#ifdef DEBUG
extern void
buf_dump ( id, all )
int id;
int all;
{
int i;
BUFHDR_T *bhp;
printf ( "LRU + %d\n", *buf_lru );
if ( all ) {
printf("ID\tFID\tPID\tLNEXT\tLPREV\tHNEXT\tHPREV\tSLEEP\tFLAG\tREFS\n");
for ( bhp = bufhdr_table, i = 0; i < NUM_BUFS; bhp++, i++ ) {
printf ( "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%x\t%d\n", i,
bhp->id.file_id, bhp->id.obj_id,
bhp->lru.next, bhp->lru.prev,
bhp->hash.next, bhp->hash.prev,
bhp->wait_proc, bhp->flags, bhp->refcount );
}
} else {
if ( id >= NUM_BUFS ) {
printf ( "Buffer ID (%d) too high\n", id );
return;
}
bhp = bufhdr_table+id;
printf ( "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%x\t%d\n", i,
bhp->id.file_id, bhp->id.obj_id,
bhp->lru.next, bhp->lru.prev,
bhp->hash.next, bhp->hash.prev,
bhp->wait_proc, bhp->flags, bhp->refcount );
}
return;
}
#endif
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