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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 1/4] block: rename blk_io_plug_call() API to defer_call()
Prepare to move the blk_io_plug_call() API out of the block layer so
that other subsystems call use this deferred call mechanism. Rename it
to defer_call() but leave the code in block/plug.c.
The next commit will move the code out of the block layer.
Suggested-by: Ilya Maximets <i.maximets@xxxxxxx>
Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
Reviewed-by: Paul Durrant <paul@xxxxxxx>
Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
---
include/sysemu/block-backend-io.h | 6 +-
block/blkio.c | 8 +--
block/io_uring.c | 4 +-
block/linux-aio.c | 4 +-
block/nvme.c | 4 +-
block/plug.c | 109 +++++++++++++++---------------
hw/block/dataplane/xen-block.c | 10 +--
hw/block/virtio-blk.c | 4 +-
hw/scsi/virtio-scsi.c | 6 +-
9 files changed, 76 insertions(+), 79 deletions(-)
diff --git a/include/sysemu/block-backend-io.h
b/include/sysemu/block-backend-io.h
index be4dcef59d..cfcfd85c1d 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -100,9 +100,9 @@ void blk_iostatus_set_err(BlockBackend *blk, int error);
int blk_get_max_iov(BlockBackend *blk);
int blk_get_max_hw_iov(BlockBackend *blk);
-void blk_io_plug(void);
-void blk_io_unplug(void);
-void blk_io_plug_call(void (*fn)(void *), void *opaque);
+void defer_call_begin(void);
+void defer_call_end(void);
+void defer_call(void (*fn)(void *), void *opaque);
AioContext *blk_get_aio_context(BlockBackend *blk);
BlockAcctStats *blk_get_stats(BlockBackend *blk);
diff --git a/block/blkio.c b/block/blkio.c
index 1dd495617c..7cf6d61f47 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -312,10 +312,10 @@ static void blkio_detach_aio_context(BlockDriverState *bs)
}
/*
- * Called by blk_io_unplug() or immediately if not plugged. Called without
- * blkio_lock.
+ * Called by defer_call_end() or immediately if not in a deferred section.
+ * Called without blkio_lock.
*/
-static void blkio_unplug_fn(void *opaque)
+static void blkio_deferred_fn(void *opaque)
{
BDRVBlkioState *s = opaque;
@@ -332,7 +332,7 @@ static void blkio_submit_io(BlockDriverState *bs)
{
BDRVBlkioState *s = bs->opaque;
- blk_io_plug_call(blkio_unplug_fn, s);
+ defer_call(blkio_deferred_fn, s);
}
static int coroutine_fn
diff --git a/block/io_uring.c b/block/io_uring.c
index 69d9820928..8429f341be 100644
--- a/block/io_uring.c
+++ b/block/io_uring.c
@@ -306,7 +306,7 @@ static void ioq_init(LuringQueue *io_q)
io_q->blocked = false;
}
-static void luring_unplug_fn(void *opaque)
+static void luring_deferred_fn(void *opaque)
{
LuringState *s = opaque;
trace_luring_unplug_fn(s, s->io_q.blocked, s->io_q.in_queue,
@@ -367,7 +367,7 @@ static int luring_do_submit(int fd, LuringAIOCB *luringcb,
LuringState *s,
return ret;
}
- blk_io_plug_call(luring_unplug_fn, s);
+ defer_call(luring_deferred_fn, s);
}
return 0;
}
diff --git a/block/linux-aio.c b/block/linux-aio.c
index 1a51503271..49a37174c2 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -353,7 +353,7 @@ static uint64_t laio_max_batch(LinuxAioState *s, uint64_t
dev_max_batch)
return max_batch;
}
-static void laio_unplug_fn(void *opaque)
+static void laio_deferred_fn(void *opaque)
{
LinuxAioState *s = opaque;
@@ -393,7 +393,7 @@ static int laio_do_submit(int fd, struct qemu_laiocb
*laiocb, off_t offset,
if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch)) {
ioq_submit(s);
} else {
- blk_io_plug_call(laio_unplug_fn, s);
+ defer_call(laio_deferred_fn, s);
}
}
diff --git a/block/nvme.c b/block/nvme.c
index b6e95f0b7e..dfbd1085fd 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -476,7 +476,7 @@ static void nvme_trace_command(const NvmeCmd *cmd)
}
}
-static void nvme_unplug_fn(void *opaque)
+static void nvme_deferred_fn(void *opaque)
{
NVMeQueuePair *q = opaque;
@@ -503,7 +503,7 @@ static void nvme_submit_command(NVMeQueuePair *q,
NVMeRequest *req,
q->need_kick++;
qemu_mutex_unlock(&q->lock);
- blk_io_plug_call(nvme_unplug_fn, q);
+ defer_call(nvme_deferred_fn, q);
}
static void nvme_admin_cmd_sync_cb(void *opaque, int ret)
diff --git a/block/plug.c b/block/plug.c
index 98a155d2f4..f26173559c 100644
--- a/block/plug.c
+++ b/block/plug.c
@@ -1,24 +1,21 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
- * Block I/O plugging
+ * Deferred calls
*
* Copyright Red Hat.
*
- * This API defers a function call within a blk_io_plug()/blk_io_unplug()
+ * This API defers a function call within a defer_call_begin()/defer_call_end()
* section, allowing multiple calls to batch up. This is a performance
* optimization that is used in the block layer to submit several I/O requests
* at once instead of individually:
*
- * blk_io_plug(); <-- start of plugged region
+ * defer_call_begin(); <-- start of section
* ...
- * blk_io_plug_call(my_func, my_obj); <-- deferred my_func(my_obj) call
- * blk_io_plug_call(my_func, my_obj); <-- another
- * blk_io_plug_call(my_func, my_obj); <-- another
+ * defer_call(my_func, my_obj); <-- deferred my_func(my_obj) call
+ * defer_call(my_func, my_obj); <-- another
+ * defer_call(my_func, my_obj); <-- another
* ...
- * blk_io_unplug(); <-- end of plugged region, my_func(my_obj) is called once
- *
- * This code is actually generic and not tied to the block layer. If another
- * subsystem needs this functionality, it could be renamed.
+ * defer_call_end(); <-- end of section, my_func(my_obj) is called once
*/
#include "qemu/osdep.h"
@@ -27,66 +24,66 @@
#include "qemu/thread.h"
#include "sysemu/block-backend.h"
-/* A function call that has been deferred until unplug() */
+/* A function call that has been deferred until defer_call_end() */
typedef struct {
void (*fn)(void *);
void *opaque;
-} UnplugFn;
+} DeferredCall;
/* Per-thread state */
typedef struct {
- unsigned count; /* how many times has plug() been called? */
- GArray *unplug_fns; /* functions to call at unplug time */
-} Plug;
+ unsigned nesting_level;
+ GArray *deferred_call_array;
+} DeferCallThreadState;
-/* Use get_ptr_plug() to fetch this thread-local value */
-QEMU_DEFINE_STATIC_CO_TLS(Plug, plug);
+/* Use get_ptr_defer_call_thread_state() to fetch this thread-local value */
+QEMU_DEFINE_STATIC_CO_TLS(DeferCallThreadState, defer_call_thread_state);
/* Called at thread cleanup time */
-static void blk_io_plug_atexit(Notifier *n, void *value)
+static void defer_call_atexit(Notifier *n, void *value)
{
- Plug *plug = get_ptr_plug();
- g_array_free(plug->unplug_fns, TRUE);
+ DeferCallThreadState *thread_state = get_ptr_defer_call_thread_state();
+ g_array_free(thread_state->deferred_call_array, TRUE);
}
/* This won't involve coroutines, so use __thread */
-static __thread Notifier blk_io_plug_atexit_notifier;
+static __thread Notifier defer_call_atexit_notifier;
/**
- * blk_io_plug_call:
+ * defer_call:
* @fn: a function pointer to be invoked
* @opaque: a user-defined argument to @fn()
*
- * Call @fn(@opaque) immediately if not within a blk_io_plug()/blk_io_unplug()
- * section.
+ * Call @fn(@opaque) immediately if not within a
+ * defer_call_begin()/defer_call_end() section.
*
* Otherwise defer the call until the end of the outermost
- * blk_io_plug()/blk_io_unplug() section in this thread. If the same
+ * defer_call_begin()/defer_call_end() section in this thread. If the same
* @fn/@opaque pair has already been deferred, it will only be called once upon
- * blk_io_unplug() so that accumulated calls are batched into a single call.
+ * defer_call_end() so that accumulated calls are batched into a single call.
*
* The caller must ensure that @opaque is not freed before @fn() is invoked.
*/
-void blk_io_plug_call(void (*fn)(void *), void *opaque)
+void defer_call(void (*fn)(void *), void *opaque)
{
- Plug *plug = get_ptr_plug();
+ DeferCallThreadState *thread_state = get_ptr_defer_call_thread_state();
- /* Call immediately if we're not plugged */
- if (plug->count == 0) {
+ /* Call immediately if we're not deferring calls */
+ if (thread_state->nesting_level == 0) {
fn(opaque);
return;
}
- GArray *array = plug->unplug_fns;
+ GArray *array = thread_state->deferred_call_array;
if (!array) {
- array = g_array_new(FALSE, FALSE, sizeof(UnplugFn));
- plug->unplug_fns = array;
- blk_io_plug_atexit_notifier.notify = blk_io_plug_atexit;
- qemu_thread_atexit_add(&blk_io_plug_atexit_notifier);
+ array = g_array_new(FALSE, FALSE, sizeof(DeferredCall));
+ thread_state->deferred_call_array = array;
+ defer_call_atexit_notifier.notify = defer_call_atexit;
+ qemu_thread_atexit_add(&defer_call_atexit_notifier);
}
- UnplugFn *fns = (UnplugFn *)array->data;
- UnplugFn new_fn = {
+ DeferredCall *fns = (DeferredCall *)array->data;
+ DeferredCall new_fn = {
.fn = fn,
.opaque = opaque,
};
@@ -106,46 +103,46 @@ void blk_io_plug_call(void (*fn)(void *), void *opaque)
}
/**
- * blk_io_plug: Defer blk_io_plug_call() functions until blk_io_unplug()
+ * defer_call_begin: Defer defer_call() functions until defer_call_end()
*
- * blk_io_plug/unplug are thread-local operations. This means that multiple
- * threads can simultaneously call plug/unplug, but the caller must ensure that
- * each unplug() is called in the same thread of the matching plug().
+ * defer_call_begin() and defer_call_end() are thread-local operations. The
+ * caller must ensure that each defer_call_begin() has a matching
+ * defer_call_end() in the same thread.
*
- * Nesting is supported. blk_io_plug_call() functions are only called at the
- * outermost blk_io_unplug().
+ * Nesting is supported. defer_call() functions are only called at the
+ * outermost defer_call_end().
*/
-void blk_io_plug(void)
+void defer_call_begin(void)
{
- Plug *plug = get_ptr_plug();
+ DeferCallThreadState *thread_state = get_ptr_defer_call_thread_state();
- assert(plug->count < UINT32_MAX);
+ assert(thread_state->nesting_level < UINT32_MAX);
- plug->count++;
+ thread_state->nesting_level++;
}
/**
- * blk_io_unplug: Run any pending blk_io_plug_call() functions
+ * defer_call_end: Run any pending defer_call() functions
*
- * There must have been a matching blk_io_plug() call in the same thread prior
- * to this blk_io_unplug() call.
+ * There must have been a matching defer_call_begin() call in the same thread
+ * prior to this defer_call_end() call.
*/
-void blk_io_unplug(void)
+void defer_call_end(void)
{
- Plug *plug = get_ptr_plug();
+ DeferCallThreadState *thread_state = get_ptr_defer_call_thread_state();
- assert(plug->count > 0);
+ assert(thread_state->nesting_level > 0);
- if (--plug->count > 0) {
+ if (--thread_state->nesting_level > 0) {
return;
}
- GArray *array = plug->unplug_fns;
+ GArray *array = thread_state->deferred_call_array;
if (!array) {
return;
}
- UnplugFn *fns = (UnplugFn *)array->data;
+ DeferredCall *fns = (DeferredCall *)array->data;
for (guint i = 0; i < array->len; i++) {
fns[i].fn(fns[i].opaque);
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index 3b6f2b0aa2..e9dd8f8a99 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -509,7 +509,7 @@ static int xen_block_get_request(XenBlockDataPlane
*dataplane,
/*
* Threshold of in-flight requests above which we will start using
- * blk_io_plug()/blk_io_unplug() to batch requests.
+ * defer_call_begin()/defer_call_end() to batch requests.
*/
#define IO_PLUG_THRESHOLD 1
@@ -537,7 +537,7 @@ static bool xen_block_handle_requests(XenBlockDataPlane
*dataplane)
* is below us.
*/
if (inflight_atstart > IO_PLUG_THRESHOLD) {
- blk_io_plug();
+ defer_call_begin();
}
while (rc != rp) {
/* pull request from ring */
@@ -577,12 +577,12 @@ static bool xen_block_handle_requests(XenBlockDataPlane
*dataplane)
if (inflight_atstart > IO_PLUG_THRESHOLD &&
batched >= inflight_atstart) {
- blk_io_unplug();
+ defer_call_end();
}
xen_block_do_aio(request);
if (inflight_atstart > IO_PLUG_THRESHOLD) {
if (batched >= inflight_atstart) {
- blk_io_plug();
+ defer_call_begin();
batched = 0;
} else {
batched++;
@@ -590,7 +590,7 @@ static bool xen_block_handle_requests(XenBlockDataPlane
*dataplane)
}
}
if (inflight_atstart > IO_PLUG_THRESHOLD) {
- blk_io_unplug();
+ defer_call_end();
}
return done_something;
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 39e7f23fab..6a45033d15 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1134,7 +1134,7 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
bool suppress_notifications = virtio_queue_get_notification(vq);
aio_context_acquire(blk_get_aio_context(s->blk));
- blk_io_plug();
+ defer_call_begin();
do {
if (suppress_notifications) {
@@ -1158,7 +1158,7 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
virtio_blk_submit_multireq(s, &mrb);
}
- blk_io_unplug();
+ defer_call_end();
aio_context_release(blk_get_aio_context(s->blk));
}
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 45b95ea070..c2465e3e88 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -799,7 +799,7 @@ static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI
*s, VirtIOSCSIReq *req)
return -ENOBUFS;
}
scsi_req_ref(req->sreq);
- blk_io_plug();
+ defer_call_begin();
object_unref(OBJECT(d));
return 0;
}
@@ -810,7 +810,7 @@ static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI
*s, VirtIOSCSIReq *req)
if (scsi_req_enqueue(sreq)) {
scsi_req_continue(sreq);
}
- blk_io_unplug();
+ defer_call_end();
scsi_req_unref(sreq);
}
@@ -836,7 +836,7 @@ static void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s,
VirtQueue *vq)
while (!QTAILQ_EMPTY(&reqs)) {
req = QTAILQ_FIRST(&reqs);
QTAILQ_REMOVE(&reqs, req, next);
- blk_io_unplug();
+ defer_call_end();
scsi_req_unref(req->sreq);
virtqueue_detach_element(req->vq, &req->elem, 0);
virtio_scsi_free_req(req);
--
2.41.0
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