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linux-aio: share one LinuxAioState within an AioContext 

This has better performance because it executes fewer system calls
and does not use a bottom half per disk.

Originally proposed by Ming Lei.

[Changed #include "raw-aio.h" to "block/raw-aio.h" in win32-aio.c to fix
build error as reported by Peter Maydell <peter.maydell@linaro.org>.
--Stefan]

Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1467650000-51385-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

squash! linux-aio: share one LinuxAioState within an AioContext
pull/42/head
Paolo Bonzini 10 years ago
committed by Stefan Hajnoczi
parent
4e90ccc28e
commit
0187f5c9cb
7 changed files with 58 additions and 111 deletions
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  1. 23
      async.c
  2. 10
      block/linux-aio.c
  3. 119
      block/raw-posix.c
  4. 2
      block/raw-win32.c
  5. 2
      block/win32-aio.c
  6. 13
      include/block/aio.h
  7. 0
      include/block/raw-aio.h

23
async.c
View File

@ -29,6 +29,7 @@
#include "block/thread-pool.h"
#include "qemu/main-loop.h"
#include "qemu/atomic.h"
#include "block/raw-aio.h"
/***********************************************************/
/* bottom halves (can be seen as timers which expire ASAP) */
@ -242,6 +243,14 @@ aio_ctx_finalize(GSource *source)
qemu_bh_delete(ctx->notify_dummy_bh);
thread_pool_free(ctx->thread_pool);
#ifdef CONFIG_LINUX_AIO
if (ctx->linux_aio) {
laio_detach_aio_context(ctx->linux_aio, ctx);
laio_cleanup(ctx->linux_aio);
ctx->linux_aio = NULL;
}
#endif
qemu_mutex_lock(&ctx->bh_lock);
while (ctx->first_bh) {
QEMUBH *next = ctx->first_bh->next;
@ -282,6 +291,17 @@ ThreadPool *aio_get_thread_pool(AioContext *ctx)
return ctx->thread_pool;
}
#ifdef CONFIG_LINUX_AIO
LinuxAioState *aio_get_linux_aio(AioContext *ctx)
{
if (!ctx->linux_aio) {
ctx->linux_aio = laio_init();
laio_attach_aio_context(ctx->linux_aio, ctx);
}
return ctx->linux_aio;
}
#endif
void aio_notify(AioContext *ctx)
{
/* Write e.g. bh->scheduled before reading ctx->notify_me. Pairs
@ -345,6 +365,9 @@ AioContext *aio_context_new(Error **errp)
false,
(EventNotifierHandler *)
event_notifier_dummy_cb);
#ifdef CONFIG_LINUX_AIO
ctx->linux_aio = NULL;
#endif
ctx->thread_pool = NULL;
qemu_mutex_init(&ctx->bh_lock);
rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);

10
block/linux-aio.c
View File

@ -50,6 +50,8 @@ typedef struct {
} LaioQueue;
struct LinuxAioState {
AioContext *aio_context;
io_context_t ctx;
EventNotifier e;
@ -227,15 +229,14 @@ static void ioq_submit(LinuxAioState *s)
void laio_io_plug(BlockDriverState *bs, LinuxAioState *s)
{
assert(!s->io_q.plugged);
s->io_q.plugged = 1;
s->io_q.plugged++;
}
void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s)
{
assert(s->io_q.plugged);
s->io_q.plugged = 0;
if (!s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
if (--s->io_q.plugged == 0 &&
!s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
ioq_submit(s);
}
}
@ -325,6 +326,7 @@ void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
{
s->aio_context = new_context;
s->completion_bh = aio_bh_new(new_context, qemu_laio_completion_bh, s);
aio_set_event_notifier(new_context, &s->e, false,
qemu_laio_completion_cb);

119
block/raw-posix.c
View File

@ -32,7 +32,7 @@
#include "trace.h"
#include "block/thread-pool.h"
#include "qemu/iov.h"
#include "raw-aio.h"
#include "block/raw-aio.h"
#include "qapi/util.h"
#include "qapi/qmp/qstring.h"
@ -137,10 +137,6 @@ typedef struct BDRVRawState {
int open_flags;
size_t buf_align;
#ifdef CONFIG_LINUX_AIO
int use_aio;
LinuxAioState *aio_ctx;
#endif
#ifdef CONFIG_XFS
bool is_xfs:1;
#endif
@ -154,9 +150,6 @@ typedef struct BDRVRawState {
typedef struct BDRVRawReopenState {
int fd;
int open_flags;
#ifdef CONFIG_LINUX_AIO
int use_aio;
#endif
} BDRVRawReopenState;
static int fd_open(BlockDriverState *bs);
@ -374,58 +367,15 @@ static void raw_parse_flags(int bdrv_flags, int *open_flags)
}
}
static void raw_detach_aio_context(BlockDriverState *bs)
{
#ifdef CONFIG_LINUX_AIO
BDRVRawState *s = bs->opaque;
if (s->use_aio) {
laio_detach_aio_context(s->aio_ctx, bdrv_get_aio_context(bs));
}
#endif
}
static void raw_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
static bool raw_use_aio(int bdrv_flags)
{
#ifdef CONFIG_LINUX_AIO
BDRVRawState *s = bs->opaque;
if (s->use_aio) {
laio_attach_aio_context(s->aio_ctx, new_context);
}
#endif
}
#ifdef CONFIG_LINUX_AIO
static int raw_set_aio(LinuxAioState **aio_ctx, int *use_aio, int bdrv_flags)
{
int ret = -1;
assert(aio_ctx != NULL);
assert(use_aio != NULL);
/*
* Currently Linux do AIO only for files opened with O_DIRECT
* specified so check NOCACHE flag too
*/
if ((bdrv_flags & (BDRV_O_NOCACHE|BDRV_O_NATIVE_AIO)) ==
(BDRV_O_NOCACHE|BDRV_O_NATIVE_AIO)) {
/* if non-NULL, laio_init() has already been run */
if (*aio_ctx == NULL) {
*aio_ctx = laio_init();
if (!*aio_ctx) {
goto error;
}
}
*use_aio = 1;
} else {
*use_aio = 0;
}
ret = 0;
error:
return ret;
return (bdrv_flags & (BDRV_O_NOCACHE|BDRV_O_NATIVE_AIO)) ==
(BDRV_O_NOCACHE|BDRV_O_NATIVE_AIO);
}
#endif
@ -494,13 +444,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
s->fd = fd;
#ifdef CONFIG_LINUX_AIO
if (raw_set_aio(&s->aio_ctx, &s->use_aio, bdrv_flags)) {
qemu_close(fd);
ret = -errno;
error_setg_errno(errp, -ret, "Could not set AIO state");
goto fail;
}
if (!s->use_aio && (bdrv_flags & BDRV_O_NATIVE_AIO)) {
if (!raw_use_aio(bdrv_flags) && (bdrv_flags & BDRV_O_NATIVE_AIO)) {
error_setg(errp, "aio=native was specified, but it requires "
"cache.direct=on, which was not specified.");
ret = -EINVAL;
@ -567,8 +511,6 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
}
#endif
raw_attach_aio_context(bs, bdrv_get_aio_context(bs));
ret = 0;
fail:
if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) {
@ -603,18 +545,6 @@ static int raw_reopen_prepare(BDRVReopenState *state,
state->opaque = g_new0(BDRVRawReopenState, 1);
raw_s = state->opaque;
#ifdef CONFIG_LINUX_AIO
raw_s->use_aio = s->use_aio;
/* we can use s->aio_ctx instead of a copy, because the use_aio flag is
* valid in the 'false' condition even if aio_ctx is set, and raw_set_aio()
* won't override aio_ctx if aio_ctx is non-NULL */
if (raw_set_aio(&s->aio_ctx, &raw_s->use_aio, state->flags)) {
error_setg(errp, "Could not set AIO state");
return -1;
}
#endif
if (s->type == FTYPE_CD) {
raw_s->open_flags |= O_NONBLOCK;
}
@ -689,9 +619,6 @@ static void raw_reopen_commit(BDRVReopenState *state)
qemu_close(s->fd);
s->fd = raw_s->fd;
#ifdef CONFIG_LINUX_AIO
s->use_aio = raw_s->use_aio;
#endif
g_free(state->opaque);
state->opaque = NULL;
@ -1329,9 +1256,10 @@ static int coroutine_fn raw_co_prw(BlockDriverState *bs, uint64_t offset,
if (!bdrv_qiov_is_aligned(bs, qiov)) {
type |= QEMU_AIO_MISALIGNED;
#ifdef CONFIG_LINUX_AIO
} else if (s->use_aio) {
} else if (bs->open_flags & BDRV_O_NATIVE_AIO) {
LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
assert(qiov->size == bytes);
return laio_co_submit(bs, s->aio_ctx, s->fd, offset, qiov, type);
return laio_co_submit(bs, aio, s->fd, offset, qiov, type);
#endif
}
}
@ -1357,9 +1285,9 @@ static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
static void raw_aio_plug(BlockDriverState *bs)
{
#ifdef CONFIG_LINUX_AIO
BDRVRawState *s = bs->opaque;
if (s->use_aio) {
laio_io_plug(bs, s->aio_ctx);
if (bs->open_flags & BDRV_O_NATIVE_AIO) {
LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
laio_io_plug(bs, aio);
}
#endif
}
@ -1367,9 +1295,9 @@ static void raw_aio_plug(BlockDriverState *bs)
static void raw_aio_unplug(BlockDriverState *bs)
{
#ifdef CONFIG_LINUX_AIO
BDRVRawState *s = bs->opaque;
if (s->use_aio) {
laio_io_unplug(bs, s->aio_ctx);
if (bs->open_flags & BDRV_O_NATIVE_AIO) {
LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
laio_io_unplug(bs, aio);
}
#endif
}
@ -1389,13 +1317,6 @@ static void raw_close(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
raw_detach_aio_context(bs);
#ifdef CONFIG_LINUX_AIO
if (s->use_aio) {
laio_cleanup(s->aio_ctx);
}
#endif
if (s->fd >= 0) {
qemu_close(s->fd);
s->fd = -1;
@ -1954,9 +1875,6 @@ BlockDriver bdrv_file = {
.bdrv_get_allocated_file_size
= raw_get_allocated_file_size,
.bdrv_detach_aio_context = raw_detach_aio_context,
.bdrv_attach_aio_context = raw_attach_aio_context,
.create_opts = &raw_create_opts,
};
@ -2402,9 +2320,6 @@ static BlockDriver bdrv_host_device = {
.bdrv_probe_blocksizes = hdev_probe_blocksizes,
.bdrv_probe_geometry = hdev_probe_geometry,
.bdrv_detach_aio_context = raw_detach_aio_context,
.bdrv_attach_aio_context = raw_attach_aio_context,
/* generic scsi device */
#ifdef __linux__
.bdrv_aio_ioctl = hdev_aio_ioctl,
@ -2524,9 +2439,6 @@ static BlockDriver bdrv_host_cdrom = {
.bdrv_get_allocated_file_size
= raw_get_allocated_file_size,
.bdrv_detach_aio_context = raw_detach_aio_context,
.bdrv_attach_aio_context = raw_attach_aio_context,
/* removable device support */
.bdrv_is_inserted = cdrom_is_inserted,
.bdrv_eject = cdrom_eject,
@ -2657,9 +2569,6 @@ static BlockDriver bdrv_host_cdrom = {
.bdrv_get_allocated_file_size
= raw_get_allocated_file_size,
.bdrv_detach_aio_context = raw_detach_aio_context,
.bdrv_attach_aio_context = raw_attach_aio_context,
/* removable device support */
.bdrv_is_inserted = cdrom_is_inserted,
.bdrv_eject = cdrom_eject,

2
block/raw-win32.c
View File

@ -27,7 +27,7 @@
#include "qemu/timer.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "raw-aio.h"
#include "block/raw-aio.h"
#include "trace.h"
#include "block/thread-pool.h"
#include "qemu/iov.h"

2
block/win32-aio.c
View File

@ -27,7 +27,7 @@
#include "block/block_int.h"
#include "qemu/module.h"
#include "block/aio.h"
#include "raw-aio.h"
#include "block/raw-aio.h"
#include "qemu/event_notifier.h"
#include "qemu/iov.h"
#include <windows.h>

13
include/block/aio.h
View File

@ -47,6 +47,9 @@ typedef struct AioHandler AioHandler;
typedef void QEMUBHFunc(void *opaque);
typedef void IOHandler(void *opaque);
struct ThreadPool;
struct LinuxAioState;
struct AioContext {
GSource source;
@ -119,6 +122,13 @@ struct AioContext {
/* Thread pool for performing work and receiving completion callbacks */
struct ThreadPool *thread_pool;
#ifdef CONFIG_LINUX_AIO
/* State for native Linux AIO. Uses aio_context_acquire/release for
* locking.
*/
struct LinuxAioState *linux_aio;
#endif
/* TimerLists for calling timers - one per clock type */
QEMUTimerListGroup tlg;
@ -335,6 +345,9 @@ GSource *aio_get_g_source(AioContext *ctx);
/* Return the ThreadPool bound to this AioContext */
struct ThreadPool *aio_get_thread_pool(AioContext *ctx);
/* Return the LinuxAioState bound to this AioContext */
struct LinuxAioState *aio_get_linux_aio(AioContext *ctx);
/**
* aio_timer_new:
* @ctx: the aio context

0
block/raw-aio.h → include/block/raw-aio.h
View File

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