* [Qemu-devel] [PATCH v3 1/3] raw-posix: warn about BDRV_O_NATIVE_AIO if libaio is unavailable
2015-07-23 12:48 [Qemu-devel] [PATCH v3 0/3] block: warn about aio=native if libaio is unavailable Stefan Hajnoczi
@ 2015-07-23 12:48 ` Stefan Hajnoczi
2015-07-23 12:48 ` [Qemu-devel] [PATCH v3 2/3] blockdev: always compile in -drive aio= parsing Stefan Hajnoczi
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Hajnoczi @ 2015-07-23 12:48 UTC (permalink / raw)
To: qemu-devel; +Cc: Kevin Wolf, Stefan Hajnoczi, Markus Armbruster, qemu-block
raw-posix.c silently ignores BDRV_O_NATIVE_AIO if libaio is unavailable.
It is confusing when aio=native performance is identical to aio=threads
because the binary was accidentally built without libaio.
Print a deprecation warning if -drive aio=native is used with a binary
that does not support libaio. There are probably users using aio=native
who would be inconvenienced if QEMU suddenly refused to start their
guests. In the future this will become an error.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
block/raw-posix.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 855febe..e09019c 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -519,7 +519,16 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
"future QEMU versions.\n",
bs->filename);
}
-#endif
+#else
+ if (bdrv_flags & BDRV_O_NATIVE_AIO) {
+ error_printf("WARNING: aio=native was specified for '%s', but "
+ "is not supported in this build. Falling back to "
+ "aio=threads.\n"
+ " This will become an error condition in "
+ "future QEMU versions.\n",
+ bs->filename);
+ }
+#endif /* !defined(CONFIG_LINUX_AIO) */
s->has_discard = true;
s->has_write_zeroes = true;
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH v3 2/3] blockdev: always compile in -drive aio= parsing
2015-07-23 12:48 [Qemu-devel] [PATCH v3 0/3] block: warn about aio=native if libaio is unavailable Stefan Hajnoczi
2015-07-23 12:48 ` [Qemu-devel] [PATCH v3 1/3] raw-posix: warn about BDRV_O_NATIVE_AIO " Stefan Hajnoczi
@ 2015-07-23 12:48 ` Stefan Hajnoczi
2015-07-23 12:48 ` [Qemu-devel] [PATCH v3 3/3] qemu-nbd: always compile in --aio=MODE option Stefan Hajnoczi
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Hajnoczi @ 2015-07-23 12:48 UTC (permalink / raw)
To: qemu-devel; +Cc: Kevin Wolf, Stefan Hajnoczi, Markus Armbruster, qemu-block
CONFIG_LINUX_AIO is an implementation detail of raw-posix.c. Don't
mention CONFIG_LINUX_AIO in blockdev.c. Let block drivers decide what
to do with BDRV_O_NATIVE_AIO. They may print an error if it is
unsupported.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockdev.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 62a4586..37b91c8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -405,7 +405,6 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
bdrv_flags |= BDRV_O_NO_FLUSH;
}
-#ifdef CONFIG_LINUX_AIO
if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
if (!strcmp(buf, "native")) {
bdrv_flags |= BDRV_O_NATIVE_AIO;
@@ -416,7 +415,6 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
goto early_err;
}
}
-#endif
if ((buf = qemu_opt_get(opts, "format")) != NULL) {
if (is_help_option(buf)) {
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH v3 3/3] qemu-nbd: always compile in --aio=MODE option
2015-07-23 12:48 [Qemu-devel] [PATCH v3 0/3] block: warn about aio=native if libaio is unavailable Stefan Hajnoczi
2015-07-23 12:48 ` [Qemu-devel] [PATCH v3 1/3] raw-posix: warn about BDRV_O_NATIVE_AIO " Stefan Hajnoczi
2015-07-23 12:48 ` [Qemu-devel] [PATCH v3 2/3] blockdev: always compile in -drive aio= parsing Stefan Hajnoczi
@ 2015-07-23 12:48 ` Stefan Hajnoczi
2015-07-23 14:45 ` [Qemu-devel] [PATCH v3 0/3] block: warn about aio=native if libaio is unavailable Markus Armbruster
2015-07-24 13:21 ` Kevin Wolf
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Hajnoczi @ 2015-07-23 12:48 UTC (permalink / raw)
To: qemu-devel; +Cc: Kevin Wolf, Stefan Hajnoczi, Markus Armbruster, qemu-block
The --aio=MODE option enables Linux AIO or Windows overlapped I/O.
The #ifdef CONFIG_LINUX_AIO was a layering violation that also prevented
Windows overlapped I/O from being used.
Now that raw-posix.c prints an error when Linux AIO has not been
compiled in, we can unconditionally compile the option into qemu-nbd.
After this patch qemu-nbd --aio=native works on Windows.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
qemu-nbd.c | 8 --------
1 file changed, 8 deletions(-)
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 5106b80..a36f0f5 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -98,9 +98,7 @@ static void usage(const char *name)
" '[ID_OR_NAME]'\n"
" -n, --nocache disable host cache\n"
" --cache=MODE set cache mode (none, writeback, ...)\n"
-#ifdef CONFIG_LINUX_AIO
" --aio=MODE set AIO mode (native or threads)\n"
-#endif
" --discard=MODE set discard mode (ignore, unmap)\n"
" --detect-zeroes=MODE set detect-zeroes mode (off, on, discard)\n"
"\n"
@@ -429,9 +427,7 @@ int main(int argc, char **argv)
{ "load-snapshot", 1, NULL, 'l' },
{ "nocache", 0, NULL, 'n' },
{ "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
-#ifdef CONFIG_LINUX_AIO
{ "aio", 1, NULL, QEMU_NBD_OPT_AIO },
-#endif
{ "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
{ "detect-zeroes", 1, NULL, QEMU_NBD_OPT_DETECT_ZEROES },
{ "shared", 1, NULL, 'e' },
@@ -450,9 +446,7 @@ int main(int argc, char **argv)
int fd;
bool seen_cache = false;
bool seen_discard = false;
-#ifdef CONFIG_LINUX_AIO
bool seen_aio = false;
-#endif
pthread_t client_thread;
const char *fmt = NULL;
Error *local_err = NULL;
@@ -485,7 +479,6 @@ int main(int argc, char **argv)
errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
}
break;
-#ifdef CONFIG_LINUX_AIO
case QEMU_NBD_OPT_AIO:
if (seen_aio) {
errx(EXIT_FAILURE, "--aio can only be specified once");
@@ -499,7 +492,6 @@ int main(int argc, char **argv)
errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
}
break;
-#endif
case QEMU_NBD_OPT_DISCARD:
if (seen_discard) {
errx(EXIT_FAILURE, "--discard can only be specified once");
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread