New access method for the buffer manager; write coalescing; runtime bufferManager selection and a few bufferManager bugfixes.

This commit is contained in:
Sears Russell 2007-08-20 16:25:08 +00:00
parent 90f011b049
commit 519bd515f4
3 changed files with 428 additions and 0 deletions

28
src/stasis/flags.c Normal file
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#include <stasis/common.h>
#include <stasis/flags.h>
#include <stasis/constants.h>
#ifdef BUFFER_MANAGER_TYPE
int bufferManagerType = BUFFER_MANAGER_TYPE;
#else
int bufferManagerType = BUFFER_MANAGER_HASH;
#endif
#ifdef BUFFER_MANAGER_O_DIRECT
int bufferManagerO_DIRECT = 1;
#else
int bufferManagerO_DIRECT = 0;
#endif
#ifdef BUFFER_MANAGER_FILE_HANDLE_TYPE
int bufferManagerFileHandleType = BUFFER_MANAGER_FILE_HANDLE_TYPE
#else
int bufferManagerFileHandleType = BUFFER_MANAGER_FILE_HANDLE_NON_BLOCKING;
#endif
#ifdef BUFFER_MANAGER_SLOW_HANDLE_TYPE
int bufferManagerNonBlockingSlowHandleType
= BUFFER_MANAGER_NON_BLOCKING_SLOW_HANDLE_TYPE;
#else
int bufferManagerNonBlockingSlowHandleType = IO_HANDLE_PFILE;
#endif

359
src/stasis/io/pfile.c Normal file
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#include <config.h>
#define _XOPEN_SOURCE 500
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <assert.h>
#include <stasis/common.h>
#include <stasis/io/handle.h>
#include <pthread.h>
/**
@file
Implementation of a file-backed io handle. This implementation uses
pread() and pwrite() to access the handle.
The functions defined here implement interfaces documented in handle.h
@see handle.h
*/
typedef struct pfile_impl {
pthread_mutex_t mut;
lsn_t start_pos;
lsn_t end_pos;
int fd;
int file_flags;
int file_mode;
char * filename;
} pfile_impl;
static int pfile_num_copies(stasis_handle_t *h) { return 0; }
static int pfile_num_copies_buffer(stasis_handle_t *h) { return 0; }
static int pfile_close(stasis_handle_t *h) {
pfile_impl * impl = (pfile_impl*)h->impl;
DEBUG("Closing pfile: end = %lld\n", impl->end_pos);
int fd = impl->fd;
free((void*)impl->filename);
free(impl);
free(h);
int ret = close(fd);
if(!ret) return 0;
else return errno;
}
static lsn_t pfile_start_position(stasis_handle_t *h) {
pfile_impl * impl = (pfile_impl*)h->impl;
return impl->start_pos;
}
static lsn_t pfile_end_position(stasis_handle_t *h) {
pfile_impl * impl = (pfile_impl*)h->impl;
pthread_mutex_lock(&impl->mut);
lsn_t ret = impl->end_pos;
pthread_mutex_unlock(&impl->mut);
return ret;
}
inline static int pfile_write_unlocked(int fd, lsn_t off, const byte * dat,
lsn_t len) {
int error = 0;
ssize_t bytes_written = 0;
while(bytes_written < len) {
ssize_t count = pwrite(fd,
dat + bytes_written,
len - bytes_written,
off + bytes_written);
if(count == -1) {
if(errno == EAGAIN || errno == EINTR) {
// @see file.c for an explanation; basically; we ignore these,
// and try again.
count = 0;
} else {
if(errno == EBADF) {
error = EBADF;
} else {
error = errno;
}
break;
}
}
bytes_written += count;
if(bytes_written != len) {
DEBUG("pwrite spinning\n");
}
}
return error;
}
static int pfile_read(stasis_handle_t * h, lsn_t off, byte * buf, lsn_t len) {
pfile_impl * impl = (pfile_impl*)(h->impl);
int error = 0;
if(off < impl->start_pos) {
error = EDOM;
} else if(off + len > impl->end_pos) {
error = EDOM;
} else {
ssize_t bytes_read = 0;
while(bytes_read < len) {
ssize_t count = pread(impl->fd,
buf + bytes_read,
len - bytes_read,
off + bytes_read - impl->start_pos);
if(count == -1) {
if(errno == EAGAIN || errno == EINTR) {
count = 0;
} else {
if(errno == EBADF) {
h->error = EBADF;
} else {
abort(); // XXX other errors?
}
error = errno;
break;
}
}
bytes_read += count;
if(bytes_read != len) {
DEBUG("pread spinning\n");
}
}
assert(bytes_read == len);
}
return error;
}
static int pfile_write(stasis_handle_t *h, lsn_t off, const byte *dat, lsn_t len) {
pfile_impl *impl = (pfile_impl*)(h->impl);
int error = 0;
lsn_t phys_off;
if(impl->start_pos > off) {
error = EDOM;
} else {
pthread_mutex_lock(&impl->mut);
if(impl->end_pos < off+len) {
impl->end_pos = off+len;
}
pthread_mutex_unlock(&impl->mut);
phys_off = off - impl->start_pos;
error = pfile_write_unlocked(impl->fd, phys_off, dat, len);
}
return error;
}
static int pfile_append(stasis_handle_t *h, lsn_t *off, const byte *dat, lsn_t len) {
pfile_impl *impl = (pfile_impl*)(h->impl);
pthread_mutex_lock(&impl->mut);
*off = impl->end_pos;
impl->end_pos += len;
pthread_mutex_unlock(&impl->mut);
lsn_t phys_off = *off - impl->start_pos;
int error = pfile_write_unlocked(impl->fd, phys_off, dat,len);
return error;
}
static stasis_write_buffer_t * pfile_write_buffer(stasis_handle_t * h,
lsn_t off, lsn_t len) {
stasis_write_buffer_t * ret = malloc(sizeof(stasis_write_buffer_t));
if(!ret) {
h->error = ENOMEM;
return NULL;
}
pfile_impl * impl = (pfile_impl*)h->impl;
int error = 0;
if(impl->start_pos > off) {
error = EDOM;
}
pthread_mutex_lock(&impl->mut);
if(off + len > impl->end_pos) {
impl->end_pos = off+len;
}
pthread_mutex_unlock(&impl->mut);
byte * buf;
if(!error) {
buf = malloc(len);
if(!buf) { error = ENOMEM; }
}
if(error) {
ret->h = h;
ret->off = 0;
ret->buf = 0;
ret->len = 0;
ret->impl = 0;
ret->error = error;
} else {
ret->h = h;
ret->off = off;
ret->buf = buf;
ret->len = len;
ret->impl = 0;
ret->error = 0;
}
return ret;
}
static stasis_write_buffer_t *pfile_append_buffer(stasis_handle_t * h,
lsn_t len) {
// Allocate the handle
stasis_write_buffer_t * ret = malloc(sizeof(stasis_write_buffer_t));
if(!ret) { return NULL; }
pfile_impl * impl = (pfile_impl*)h->impl;
// Obtain an appropriate offset
pthread_mutex_lock(&(impl->mut));
off_t off = impl->end_pos;
impl->end_pos += len;
pthread_mutex_unlock(&(impl->mut));
// Allocate the buffer
byte * buf = malloc(len);
int error = 0;
if(!buf) {
error = ENOMEM;
}
if(error) {
ret->h = h;
ret->off = 0;
ret->buf = 0;
ret->len = 0;
ret->impl = 0;
ret->error = error;
} else {
ret->h = h;
ret->off = off;
ret->buf = buf;
ret->len = len;
ret->impl = 0;
ret->error = 0;
}
return ret;
}
static int pfile_release_write_buffer(stasis_write_buffer_t * w) {
pfile_impl * impl = (pfile_impl*)(w->h->impl);
pthread_mutex_lock(&(impl->mut));
int error = 0;
if(impl->end_pos < w->off + w->len ||
impl->start_pos > w->off) {
error = EDOM;
}
pthread_mutex_unlock(&(impl->mut));
if(!error) {
error = pfile_write_unlocked(impl->fd, w->off-impl->start_pos, w->buf, w->len);
}
free(w->buf);
free(w);
return error;
}
static stasis_read_buffer_t * pfile_read_buffer(stasis_handle_t * h,
lsn_t off, lsn_t len) {
stasis_read_buffer_t * ret = malloc(sizeof(stasis_read_buffer_t));
if(!ret) { return NULL; }
byte * buf = malloc(len);
int error = 0;
if(!buf) { error = ENOMEM; }
if(!error) {
error = pfile_read(h, off, buf, len);
}
if(error) {
ret->h = h;
ret->buf = 0;
ret->off = 0;
ret->len = 0;
ret->impl = 0;
ret->error = error;
if(buf) { free(buf); }
} else {
ret->h = h;
ret->buf = buf;
ret->off = off;
ret->len = len;
ret->impl = 0;
ret->error = 0;
}
return ret;
}
static int pfile_release_read_buffer(stasis_read_buffer_t * r) {
free((void*)r->buf);
free(r);
return 0;
}
static int pfile_truncate_start(stasis_handle_t * h, lsn_t new_start) {
static int truncate_warned = 0;
if(!truncate_warned) {
printf("\nWarning: pfile doesn't support truncation; ignoring truncation request\n");
truncate_warned = 1;
}
return 0;
}
struct stasis_handle_t pfile_func = {
.num_copies = pfile_num_copies,
.num_copies_buffer = pfile_num_copies_buffer,
.close = pfile_close,
.start_position = pfile_start_position,
.end_position = pfile_end_position,
.write = pfile_write,
.append = pfile_append,
.write_buffer = pfile_write_buffer,
.append_buffer = pfile_append_buffer,
.release_write_buffer = pfile_release_write_buffer,
.read = pfile_read,
.read_buffer = pfile_read_buffer,
.release_read_buffer = pfile_release_read_buffer,
.truncate_start = pfile_truncate_start,
.error = 0
};
stasis_handle_t * stasis_handle(open_pfile)(lsn_t start_offset, char * filename, int flags, int mode) {
stasis_handle_t * ret = malloc(sizeof(stasis_handle_t));
if(!ret) { return NULL; }
*ret = pfile_func;
pfile_impl * impl = malloc(sizeof(pfile_impl));
ret->impl = impl;
pthread_mutex_init(&(impl->mut), 0);
impl->fd = open(filename, flags, mode);
assert(sizeof(off_t) >= (64/8));
if(impl->fd == -1) {
ret->error = errno;
}
impl->start_pos = start_offset;
off_t file_len = lseek(impl->fd,0,SEEK_END);
if(file_len == (off_t)-1) {
ret->error = errno;
}
impl->end_pos = file_len + start_offset;
DEBUG("file len = %lld, start_off = %lld, end = %lld\n", file_len, start_offset, impl->end_pos);
impl->filename = strdup(filename);
impl->file_flags = flags;
impl->file_mode = mode;
assert(!ret->error);
return ret;
}

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stasis/flags.h Normal file
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#ifndef _STASIS_FLAGS_H__
#define _STASIS_FLAGS_H__
/**
This is the type of buffer manager that is being used.
Before Stasis is intialized it will be set to a default value.
It may be changed before Tinit() is called, or overridden at
compile time by defining USE_BUFFER_MANAGER.
(eg: gcc ... -DUSE_BUFFER_MANAGER=BUFFER_MANAGER_FOO)
@see constants.h for a list of recognized buffer manager implementations.
(The constants are named BUFFER_MANAGER_*)
*/
extern int bufferManagerType;
/**
This determines which type of file handle the buffer manager will use.
It defaults to BUFFER_MANAGER_FILE_HANDLE_NON_BLOCKING for a
non-blocking handle. It can be overridden at compile time by defining
BUFFER_MANAGER_FILE_HANDLE_TYPE.
@see constants.h for potential values. (The constants are named
BUFFER_MANAGER_FILE_HANDLE_*)
*/
extern int bufferManagerFileHandleType;
/**
Determines which type of slow handle non_blocking will use for the
buffer manager. Override at compile time by defining
BUFFER_MANAGER_NON_BLOCKING_SLOW_TYPE.
@see constants.h: Constants named IO_HANDLE_* are potential values.
*/
extern int bufferManagerNonBlockingSlowHandleType;
/**
If true, the buffer manager will use O_DIRECT. Set at compile time by
#defining BUFFER_MANAGER_O_DIRECT.
*/
extern int bufferManagerO_DIRECT;
#endif