#include <unistd.h>
#include <errno.h>
#include <assert.h>
+#include <malloc.h>
#include <asm/unistd.h>
#include "../fio.h"
+#include "../indirect.h"
+#include "../syslet.h"
#ifdef FIO_HAVE_SYSLET
#define __NR_fio_pwrite __NR_pwrite
#endif
-#define ATOM_TO_IOU(p) ((struct io_u *) (unsigned long) (p))
-
struct syslet_data {
struct io_u **events;
unsigned int nr_events;
- struct async_head_user ahu;
- struct syslet_uatom **ring;
-
- struct syslet_uatom *head, *tail;
+ struct syslet_ring *ring;
+ void *stack;
};
-static void fio_syslet_complete_atom(struct thread_data *td,
- struct syslet_uatom *atom)
+static void fio_syslet_complete(struct thread_data *td, struct io_u *io_u)
{
struct syslet_data *sd = td->io_ops->data;
- struct syslet_uatom *last;
- struct io_u *io_u;
-
- /*
- * complete from the beginning of the sequence up to (and
- * including) this atom
- */
- last = atom;
- io_u = ATOM_TO_IOU(atom);
- atom = io_u->req.head;
-
- /*
- * now complete in right order
- */
- do {
- long ret;
- io_u = ATOM_TO_IOU(atom);
- ret = *(long *) (unsigned long) atom->ret_ptr;
- if (ret >= 0)
- io_u->resid = io_u->xfer_buflen - ret;
- else if (ret < 0)
- io_u->error = ret;
-
- assert(sd->nr_events < td->o.iodepth);
- sd->events[sd->nr_events++] = io_u;
+ assert(sd->nr_events < td->o.iodepth);
+ sd->events[sd->nr_events++] = io_u;
+}
- if (atom == last)
- break;
+static void syslet_complete_nr(struct thread_data *td, unsigned int nr)
+{
+ struct syslet_data *sd = td->io_ops->data;
+ unsigned int i;
- atom = (struct syslet_uatom *) (unsigned long) atom->next;
- } while (1);
+ for (i = 0; i < nr; i++) {
+ unsigned int idx = (i + sd->ring->user_tail) % td->o.iodepth;
+ struct syslet_completion *comp = &sd->ring->comp[idx];
+ struct io_u *io_u = (struct io_u *) (long) comp->caller_data;
- assert(!last->next);
+ io_u->resid = io_u->xfer_buflen - comp->status;
+ fio_syslet_complete(td, io_u);
+ }
}
-/*
- * Inspect the ring to see if we have completed events
- */
-static void fio_syslet_complete(struct thread_data *td)
+
+static void fio_syslet_wait_for_events(struct thread_data *td)
{
struct syslet_data *sd = td->io_ops->data;
+ struct syslet_ring *ring = sd->ring;
+ unsigned int events;
+ events = 0;
do {
- struct syslet_uatom *atom;
+ unsigned int kh = ring->kernel_head;
+ int ret;
- atom = sd->ring[sd->ahu.user_ring_idx];
- if (!atom)
- break;
+ /*
+ * first reap events that are already completed
+ */
+ if (ring->user_tail != kh) {
+ unsigned int nr = kh - ring->user_tail;
- sd->ring[sd->ahu.user_ring_idx] = NULL;
- if (++sd->ahu.user_ring_idx == td->o.iodepth)
- sd->ahu.user_ring_idx = 0;
+ syslet_complete_nr(td, nr);
+ events += nr;
+ ring->user_tail = kh;
+ continue;
+ }
- fio_syslet_complete_atom(td, atom);
- } while (1);
+ /*
+ * block waiting for at least one event
+ */
+ ret = syscall(__NR_syslet_ring_wait, ring, ring->user_tail);
+ assert(!ret);
+ } while (!events);
}
static int fio_syslet_getevents(struct thread_data *td, int min,
long ret;
do {
- fio_syslet_complete(td);
-
/*
* do we have enough immediate completions?
*/
if (sd->nr_events >= (unsigned int) min)
break;
- /*
- * OK, we need to wait for some events...
- */
- ret = async_wait(1, sd->ahu.user_ring_idx, &sd->ahu);
- if (ret < 0)
- return -errno;
+ fio_syslet_wait_for_events(td);
} while (1);
ret = sd->nr_events;
return sd->events[event];
}
-static void init_atom(struct syslet_uatom *atom, int nr, void *arg0,
- void *arg1, void *arg2, void *arg3, void *ret_ptr,
- unsigned long flags, void *priv)
-{
- atom->flags = flags;
- atom->nr = nr;
- atom->ret_ptr = (uint64_t) (unsigned long) ret_ptr;
- atom->next = 0;
- atom->arg_ptr[0] = (uint64_t) (unsigned long) arg0;
- atom->arg_ptr[1] = (uint64_t) (unsigned long) arg1;
- atom->arg_ptr[2] = (uint64_t) (unsigned long) arg2;
- atom->arg_ptr[3] = (uint64_t) (unsigned long) arg3;
- atom->arg_ptr[4] = 0;
- atom->arg_ptr[5] = 0;
- atom->private = (uint64_t) (unsigned long) priv;
-}
-
-/*
- * Use seek atom for sync
- */
-static void fio_syslet_prep_sync(struct io_u *io_u, struct fio_file *f)
+static void fio_syslet_prep_sync(struct fio_file *f,
+ struct indirect_registers *regs)
{
- init_atom(&io_u->req.atom, __NR_fsync, &f->fd, NULL, NULL, NULL,
- &io_u->req.ret, 0, io_u);
+ FILL_IN(*regs, __NR_fsync, (long) f->fd);
}
-static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f)
+static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f,
+ struct indirect_registers *regs)
{
- int nr;
+ long nr;
/*
* prepare rw
else
nr = __NR_fio_pwrite;
- init_atom(&io_u->req.atom, nr, &f->fd, &io_u->xfer_buf,
- &io_u->xfer_buflen, &io_u->offset, &io_u->req.ret, 0, io_u);
+ FILL_IN(*regs, nr, (long) f->fd, (long) io_u->xfer_buf,
+ (long) io_u->xfer_buflen, (long) io_u->offset);
}
-static int fio_syslet_prep(struct thread_data fio_unused *td, struct io_u *io_u)
+static void fio_syslet_prep(struct io_u *io_u, struct indirect_registers *regs)
{
struct fio_file *f = io_u->file;
if (io_u->ddir == DDIR_SYNC)
- fio_syslet_prep_sync(io_u, f);
+ fio_syslet_prep_sync(f, regs);
else
- fio_syslet_prep_rw(io_u, f);
-
- return 0;
-}
-
-static void cachemiss_thread_start(void)
-{
- while (1)
- async_thread(NULL, NULL);
-}
-
-#define THREAD_STACK_SIZE (16384)
-
-static unsigned long thread_stack_alloc()
-{
- return (unsigned long) malloc(THREAD_STACK_SIZE) + THREAD_STACK_SIZE;
-}
-
-static void fio_syslet_queued(struct thread_data *td, struct syslet_data *sd)
-{
- struct syslet_uatom *atom;
- struct timeval now;
-
- fio_gettime(&now, NULL);
-
- atom = sd->head;
- while (atom) {
- struct io_u *io_u = ATOM_TO_IOU(atom);
-
- memcpy(&io_u->issue_time, &now, sizeof(now));
- io_u_queued(td, io_u);
- atom = (struct syslet_uatom *) (unsigned long) atom->next;
- }
+ fio_syslet_prep_rw(io_u, f, regs);
}
-static int fio_syslet_commit(struct thread_data *td)
+static void ret_func(void)
{
- struct syslet_data *sd = td->io_ops->data;
- struct syslet_uatom *done;
-
- if (!sd->head)
- return 0;
-
- assert(!sd->tail->next);
-
- if (!sd->ahu.new_thread_stack)
- sd->ahu.new_thread_stack = thread_stack_alloc();
-
- fio_syslet_queued(td, sd);
-
- /*
- * On sync completion, the atom is returned. So on NULL return
- * it's queued asynchronously.
- */
- done = async_exec(sd->head, &sd->ahu);
-
- if (done == (void *) -1) {
- log_err("fio: syslets don't appear to work\n");
- return -1;
- }
-
- sd->head = sd->tail = NULL;
-
- if (done)
- fio_syslet_complete_atom(td, done);
-
- return 0;
+ syscall(__NR_exit);
}
static int fio_syslet_queue(struct thread_data *td, struct io_u *io_u)
{
struct syslet_data *sd = td->io_ops->data;
+ union indirect_params params;
+ struct indirect_registers regs;
+ int ret;
fio_ro_check(td, io_u);
- if (sd->tail) {
- sd->tail->next = (uint64_t) (unsigned long) &io_u->req.atom;
- sd->tail = &io_u->req.atom;
- } else
- sd->head = sd->tail = (struct syslet_uatom *)&io_u->req.atom;
-
- io_u->req.head = sd->head;
- return FIO_Q_QUEUED;
-}
-
-static int async_head_init(struct syslet_data *sd, unsigned int depth)
-{
- unsigned long ring_size;
+ memset(¶ms, 0, sizeof(params));
+ fill_syslet_args(¶ms.syslet, sd->ring, (long)io_u, ret_func, sd->stack);
- memset(&sd->ahu, 0, sizeof(struct async_head_user));
+ fio_syslet_prep(io_u, ®s);
- ring_size = sizeof(struct syslet_uatom *) * depth;
- sd->ring = malloc(ring_size);
- memset(sd->ring, 0, ring_size);
-
- sd->ahu.user_ring_idx = 0;
- sd->ahu.completion_ring_ptr = (uint64_t) (unsigned long) sd->ring;
- sd->ahu.ring_size_bytes = ring_size;
- sd->ahu.head_stack = thread_stack_alloc();
- sd->ahu.head_ip = (uint64_t) (unsigned long) cachemiss_thread_start;
- sd->ahu.new_thread_ip = (uint64_t) (unsigned long) cachemiss_thread_start;
- sd->ahu.new_thread_stack = thread_stack_alloc();
-
- return 0;
-}
+ ret = syscall(__NR_indirect, ®s, ¶ms, sizeof(params), 0);
+ if (ret == (int) io_u->xfer_buflen) {
+ /*
+ * completed sync, account. this also catches fsync().
+ */
+ return FIO_Q_COMPLETED;
+ } else if (ret < 0) {
+ /*
+ * queued for async execution
+ */
+ if (errno == ESYSLETPENDING)
+ return FIO_Q_QUEUED;
+ }
-static void async_head_exit(struct syslet_data *sd)
-{
- free(sd->ring);
+ io_u->error = errno;
+ td_verror(td, io_u->error, "xfer");
+ return FIO_Q_COMPLETED;
}
static int check_syslet_support(struct syslet_data *sd)
{
- struct syslet_uatom atom;
- void *ret;
+ union indirect_params params;
+ struct indirect_registers regs;
+ pid_t pid, my_pid = getpid();
- init_atom(&atom, __NR_getpid, NULL, NULL, NULL, NULL, NULL, 0, NULL);
- ret = async_exec(&atom, &sd->ahu);
- if (ret == (void *) -1)
- return 1;
+ memset(¶ms, 0, sizeof(params));
+ fill_syslet_args(¶ms.syslet, sd->ring, 0, ret_func, sd->stack);
- return 0;
+ FILL_IN(regs, __NR_getpid);
+
+ pid = syscall(__NR_indirect, ®s, ¶ms, sizeof(params), 0);
+ if (pid == my_pid)
+ return 0;
+
+ return 1;
}
static void fio_syslet_cleanup(struct thread_data *td)
struct syslet_data *sd = td->io_ops->data;
if (sd) {
- async_head_exit(sd);
free(sd->events);
+ free(sd->ring);
+ free(sd->stack);
free(sd);
td->io_ops->data = NULL;
}
static int fio_syslet_init(struct thread_data *td)
{
struct syslet_data *sd;
+ void *ring, *stack;
sd = malloc(sizeof(*sd));
memset(sd, 0, sizeof(*sd));
+
sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth);
memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth);
-
- /*
- * This will handily fail for kernels where syslet isn't available
- */
- if (async_head_init(sd, td->o.iodepth)) {
- free(sd->events);
- free(sd);
+ if (posix_memalign(&ring, sizeof(uint64_t), sizeof(struct syslet_ring)))
return 1;
- }
+ if (posix_memalign(&stack, page_size, page_size))
+ return 1;
+
+ sd->ring = ring;
+ sd->stack = stack;
+
+ memset(sd->ring, 0, sizeof(*sd->ring));
+ sd->ring->elements = td->o.iodepth;
if (check_syslet_support(sd)) {
log_err("fio: syslets do not appear to work\n");
free(sd->events);
+ free(sd->ring);
+ free(sd->stack);
free(sd);
return 1;
}
.name = "syslet-rw",
.version = FIO_IOOPS_VERSION,
.init = fio_syslet_init,
- .prep = fio_syslet_prep,
.queue = fio_syslet_queue,
- .commit = fio_syslet_commit,
.getevents = fio_syslet_getevents,
.event = fio_syslet_event,
.cleanup = fio_syslet_cleanup,
-#ifndef _LINUX_SYSLET_H
-#define _LINUX_SYSLET_H
-/*
- * The syslet subsystem - asynchronous syscall execution support.
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- *
- * User-space API/ABI definitions:
- */
+#ifndef _SYSLET_H_
+#define _SYSLET_H_
-#ifndef __user
-# define __user
-#endif
+#include "kcompat.h"
-/*
- * This is the 'Syslet Atom' - the basic unit of execution
- * within the syslet framework. A syslet always represents
- * a single system-call plus its arguments, plus has conditions
- * attached to it that allows the construction of larger
- * programs from these atoms. User-space variables can be used
- * (for example a loop index) via the special sys_umem*() syscalls.
- *
- * Arguments are implemented via pointers to arguments. This not
- * only increases the flexibility of syslet atoms (multiple syslets
- * can share the same variable for example), but is also an
- * optimization: copy_uatom() will only fetch syscall parameters
- * up until the point it meets the first NULL pointer. 50% of all
- * syscalls have 2 or less parameters (and 90% of all syscalls have
- * 4 or less parameters).
- *
- * [ Note: since the argument array is at the end of the atom, and the
- * kernel will not touch any argument beyond the final NULL one, atoms
- * might be packed more tightly. (the only special case exception to
- * this rule would be SKIP_TO_NEXT_ON_STOP atoms, where the kernel will
- * jump a full syslet_uatom number of bytes.) ]
- */
-struct syslet_uatom {
- uint32_t flags;
- uint32_t nr;
- uint64_t ret_ptr;
- uint64_t next;
- uint64_t arg_ptr[6];
- /*
- * User-space can put anything in here, kernel will not
- * touch it:
- */
- uint64_t private;
+struct syslet_frame {
+ u64 ip;
+ u64 sp;
};
-/*
- * Flags to modify/control syslet atom behavior:
- */
-
-/*
- * Immediately queue this syslet asynchronously - do not even
- * attempt to execute it synchronously in the user context:
- */
-#define SYSLET_ASYNC 0x00000001
-
-/*
- * Never queue this syslet asynchronously - even if synchronous
- * execution causes a context-switching:
- */
-#define SYSLET_SYNC 0x00000002
-
-/*
- * Do not queue the syslet in the completion ring when done.
- *
- * ( the default is that the final atom of a syslet is queued
- * in the completion ring. )
- *
- * Some syscalls generate implicit completion events of their
- * own.
- */
-#define SYSLET_NO_COMPLETE 0x00000004
-
-/*
- * Execution control: conditions upon the return code
- * of the just executed syslet atom. 'Stop' means syslet
- * execution is stopped and the atom is put into the
- * completion ring:
- */
-#define SYSLET_STOP_ON_NONZERO 0x00000008
-#define SYSLET_STOP_ON_ZERO 0x00000010
-#define SYSLET_STOP_ON_NEGATIVE 0x00000020
-#define SYSLET_STOP_ON_NON_POSITIVE 0x00000040
-
-#define SYSLET_STOP_MASK \
- ( SYSLET_STOP_ON_NONZERO | \
- SYSLET_STOP_ON_ZERO | \
- SYSLET_STOP_ON_NEGATIVE | \
- SYSLET_STOP_ON_NON_POSITIVE )
+struct syslet_args {
+ u64 ring_ptr;
+ u64 caller_data;
+ struct syslet_frame frame;
+};
-/*
- * Special modifier to 'stop' handling: instead of stopping the
- * execution of the syslet, the linearly next syslet is executed.
- * (Normal execution flows along atom->next, and execution stops
- * if atom->next is NULL or a stop condition becomes true.)
- *
- * This is what allows true branches of execution within syslets.
- */
-#define SYSLET_SKIP_TO_NEXT_ON_STOP 0x00000080
+struct syslet_completion {
+ u64 status;
+ u64 caller_data;
+};
-/*
- * This is the (per-user-context) descriptor of the async completion
- * ring. This gets passed in to sys_async_exec():
- */
-struct async_head_user {
- /*
- * Current completion ring index - managed by the kernel:
- */
- uint64_t kernel_ring_idx;
- /*
- * User-side ring index:
- */
- uint64_t user_ring_idx;
+struct syslet_ring {
+ u32 kernel_head;
+ u32 user_tail;
+ u32 elements;
+ u32 wait_group;
+ struct syslet_completion comp[0];
+};
- /*
- * Ring of pointers to completed async syslets (i.e. syslets that
- * generated a cachemiss and went async, returning -EASYNCSYSLET
- * to the user context by sys_async_exec()) are queued here.
- * Syslets that were executed synchronously (cached) are not
- * queued here.
- *
- * Note: the final atom that generated the exit condition is
- * queued here. Normally this would be the last atom of a syslet.
- */
- uint64_t completion_ring_ptr;
+#ifdef __x86_64__
+#define __NR_syslet_ring_wait 287
+#elif defined __i386__
+#define __NR_syslet_ring_wait 326
+#endif
- /*
- * Ring size in bytes:
- */
- uint64_t ring_size_bytes;
+#define ESYSLETPENDING 132
- /*
- * The head task can become a cachemiss thread later on
- * too, if it blocks - so it needs its separate thread
- * stack and start address too:
- */
- uint64_t head_stack;
- uint64_t head_ip;
+typedef void (*syslet_return_func_t)(void);
- /*
- * Newly started async kernel threads will take their
- * user stack and user start address from here. User-space
- * code has to check for new_thread_stack going to NULL
- * and has to refill it with a new stack if that happens.
- */
- uint64_t new_thread_stack;
- uint64_t new_thread_ip;
-};
+void fill_syslet_args(struct syslet_args *args, struct syslet_ring *ring,
+ uint64_t caller_data, syslet_return_func_t func,
+ void *stack)
+{
+ args->ring_ptr = (u64)(unsigned long)ring;
+ args->caller_data = caller_data;
+ args->frame.ip = (u64)(unsigned long)func;
+ args->frame.sp = (u64)(unsigned long)stack;
+}
#endif
projects / fio.git / commitdiff