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[Qemu-devel] [PATCH v3 7/7] curl: do not do aio_poll when waiting for a
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH v3 7/7] curl: do not do aio_poll when waiting for a free CURLState |
Date: |
Mon, 15 May 2017 12:00:59 +0200 |
Instead, put the CURLAIOCB on a wait list and yield; curl_clean_state will
wake the corresponding coroutine.
Because of CURL's callback-based structure, we cannot easily convert
everything to CoMutex/CoQueue; keeping the QemuMutex is simpler. However,
CoQueue is a simple wrapper around a linked list, so we can easily
use QSIMPLEQ and open-code a CoQueue, protected by the BDRVCURLState
QemuMutex instead of a CoMutex.
Reviewed-by: Jeff Cody <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/curl.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/block/curl.c b/block/curl.c
index 86a4a73834..630c6e5187 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -98,6 +98,8 @@ typedef struct CURLAIOCB {
size_t start;
size_t end;
+
+ QSIMPLEQ_ENTRY(CURLAIOCB) next;
} CURLAIOCB;
typedef struct CURLSocket {
@@ -133,6 +135,7 @@ typedef struct BDRVCURLState {
bool accept_range;
AioContext *aio_context;
QemuMutex mutex;
+ QSIMPLEQ_HEAD(, CURLAIOCB) free_state_waitq;
char *username;
char *password;
char *proxyusername;
@@ -532,6 +535,7 @@ static int curl_init_state(BDRVCURLState *s, CURLState
*state)
/* Called with s->mutex held. */
static void curl_clean_state(CURLState *s)
{
+ CURLAIOCB *next;
int j;
for (j=0; j < CURL_NUM_ACB; j++) {
assert(!s->acb[j]);
@@ -548,6 +552,14 @@ static void curl_clean_state(CURLState *s)
}
s->in_use = 0;
+
+ next = QSIMPLEQ_FIRST(&s->s->free_state_waitq);
+ if (next) {
+ QSIMPLEQ_REMOVE_HEAD(&s->s->free_state_waitq, next);
+ qemu_mutex_unlock(&s->s->mutex);
+ aio_co_wake(next->co);
+ qemu_mutex_lock(&s->s->mutex);
+ }
}
static void curl_parse_filename(const char *filename, QDict *options,
@@ -744,6 +756,7 @@ static int curl_open(BlockDriverState *bs, QDict *options,
int flags,
}
DPRINTF("CURL: Opening %s\n", file);
+ QSIMPLEQ_INIT(&s->free_state_waitq);
s->aio_context = bdrv_get_aio_context(bs);
s->url = g_strdup(file);
qemu_mutex_lock(&s->mutex);
@@ -844,8 +857,9 @@ static void curl_setup_preadv(BlockDriverState *bs,
CURLAIOCB *acb)
if (state) {
break;
}
+ QSIMPLEQ_INSERT_TAIL(&s->free_state_waitq, acb, next);
qemu_mutex_unlock(&s->mutex);
- aio_poll(bdrv_get_aio_context(bs), true);
+ qemu_coroutine_yield();
qemu_mutex_lock(&s->mutex);
}
--
2.12.2
- [Qemu-devel] [PATCH v3 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 1/7] curl: strengthen assertion in curl_clean_state, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 4/7] curl: split curl_find_state/curl_init_state, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 2/7] curl: never invoke callbacks with s->mutex held, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 5/7] curl: convert CURLAIOCB to byte values, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 3/7] curl: avoid recursive locking of BDRVCURLState mutex, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 6/7] curl: convert readv to coroutines, Paolo Bonzini, 2017/05/15
- [Qemu-devel] [PATCH v3 7/7] curl: do not do aio_poll when waiting for a free CURLState,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH v3 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, no-reply, 2017/05/15
- Re: [Qemu-devel] [Qemu-block] [PATCH v3 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, Max Reitz, 2017/05/15
- Re: [Qemu-devel] [PATCH v3 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, Jeff Cody, 2017/05/16
- Re: [Qemu-devel] [PATCH v3 0/7] curl: locking cleanups/fixes, coroutine conversion, remove aio_poll, Richard W.M. Jones, 2017/05/18