| Message ID | 1452599056-27357-9-git-send-email-berrange@redhat.com |
|---|---|
| State | New |
| Headers | show |
* Daniel P. Berrange (berrange@redhat.com) wrote: > The post-copy code does some I/O to/from an intermediate > in-memory buffer rather than direct to the underlying > I/O channel. Switch this code to use QIOChannelBuffer > instead of QEMUSizedBuffer. > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > docs/migration.txt | 4 ++-- > include/sysemu/sysemu.h | 2 +- > migration/migration.c | 15 +++++++-------- > migration/savevm.c | 41 +++++++++++++---------------------------- > 4 files changed, 23 insertions(+), 39 deletions(-) > > diff --git a/docs/migration.txt b/docs/migration.txt > index fda8d61..11703de 100644 > --- a/docs/migration.txt > +++ b/docs/migration.txt > @@ -403,8 +403,8 @@ listen thread: --- page -- page -- page -- page -- page -- > > On receipt of CMD_PACKAGED (1) > All the data associated with the package - the ( ... ) section in the > -diagram - is read into memory (into a QEMUSizedBuffer), and the main thread > -recurses into qemu_loadvm_state_main to process the contents of the package (2) > +diagram - is read into memory, and the main thread recurses into > +qemu_loadvm_state_main to process the contents of the package (2) > which contains commands (3,6) and devices (4...) > > On receipt of 'postcopy listen' - 3 -(i.e. the 1st command in the package) > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > index 3bb8897..0f59912 100644 > --- a/include/sysemu/sysemu.h > +++ b/include/sysemu/sysemu.h > @@ -120,7 +120,7 @@ void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, > uint16_t len, uint8_t *data); > void qemu_savevm_send_ping(QEMUFile *f, uint32_t value); > void qemu_savevm_send_open_return_path(QEMUFile *f); > -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb); > +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len); > void qemu_savevm_send_postcopy_advise(QEMUFile *f); > void qemu_savevm_send_postcopy_listen(QEMUFile *f); > void qemu_savevm_send_postcopy_run(QEMUFile *f); > diff --git a/migration/migration.c b/migration/migration.c > index 715f069..e921b20 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -33,6 +33,7 @@ > #include "qom/cpu.h" > #include "exec/memory.h" > #include "exec/address-spaces.h" > +#include "io/channel-buffer.h" > > #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ > > @@ -1401,7 +1402,8 @@ static int await_return_path_close_on_source(MigrationState *ms) > static int postcopy_start(MigrationState *ms, bool *old_vm_running) > { > int ret; > - const QEMUSizedBuffer *qsb; > + QIOChannelBuffer *bioc; > + QEMUFile *fb; > int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > migrate_set_state(ms, MIGRATION_STATUS_ACTIVE, > MIGRATION_STATUS_POSTCOPY_ACTIVE); > @@ -1456,11 +1458,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) > * So we wrap the device state up in a package with a length at the start; > * to do this we use a qemu_buf to hold the whole of the device state. > */ > - QEMUFile *fb = qemu_bufopen("w", NULL); > - if (!fb) { > - error_report("Failed to create buffered file"); > - goto fail; > - } > + bioc = qio_channel_buffer_new(4096); > + fb = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); Why is that _input ? Also, what's your naming converntion; my 'qsb' was just an abbreviation of (Q)EMU(S)ized(B)uffer; what's a bioc? > + object_unref(OBJECT(bioc)); > > /* > * Make sure the receiver can get incoming pages before we send the rest > @@ -1474,10 +1474,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) > qemu_savevm_send_postcopy_run(fb); > > /* <><> end of stuff going into the package */ > - qsb = qemu_buf_get(fb); > > /* Now send that blob */ > - if (qemu_savevm_send_packaged(ms->file, qsb)) { > + if (qemu_savevm_send_packaged(ms->file, bioc->data, bioc->usage)) { > goto fail_closefb; > } > qemu_fclose(fb); > diff --git a/migration/savevm.c b/migration/savevm.c > index 0ad1b93..f2e1880 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -50,6 +50,7 @@ > #include "qemu/iov.h" > #include "block/snapshot.h" > #include "block/qapi.h" > +#include "io/channel-buffer.h" > > > #ifndef ETH_P_RARP > @@ -760,10 +761,8 @@ void qemu_savevm_send_open_return_path(QEMUFile *f) > * 0 on success > * -ve on error > */ > -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) > +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len) > { > - size_t cur_iov; > - size_t len = qsb_get_length(qsb); > uint32_t tmp; > > if (len > MAX_VM_CMD_PACKAGED_SIZE) { > @@ -777,18 +776,7 @@ int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) > trace_qemu_savevm_send_packaged(); > qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); > > - /* all the data follows (concatinating the iov's) */ > - for (cur_iov = 0; cur_iov < qsb->n_iov; cur_iov++) { > - /* The iov entries are partially filled */ > - size_t towrite = MIN(qsb->iov[cur_iov].iov_len, len); > - len -= towrite; > - > - if (!towrite) { > - break; > - } > - > - qemu_put_buffer(f, qsb->iov[cur_iov].iov_base, towrite); > - } > + qemu_put_buffer(f, (const uint8_t *)buf, len); > > return 0; > } > @@ -1548,9 +1536,8 @@ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) > static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) > { > int ret; > - uint8_t *buffer; > uint32_t length; > - QEMUSizedBuffer *qsb; > + QIOChannelBuffer *bioc; > > length = qemu_get_be32(mis->from_src_file); > trace_loadvm_handle_cmd_packaged(length); > @@ -1559,28 +1546,26 @@ static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) > error_report("Unreasonably large packaged state: %u", length); > return -1; > } > - buffer = g_malloc0(length); > - ret = qemu_get_buffer(mis->from_src_file, buffer, (int)length); > + > + bioc = qio_channel_buffer_new(length); > + ret = qemu_get_buffer(mis->from_src_file, > + (uint8_t *)bioc->data, > + (int)length); Actually, qemu_get_buffer takes a size_t now; so you can fix that at the same time. > if (ret != length) { > - g_free(buffer); > + object_unref(OBJECT(bioc)); > error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%d\n", > ret, length); > return (ret < 0) ? ret : -EAGAIN; > } > + bioc->usage += length; I'm a bit surprised you've not wrapped feeding the data into the qio_channel_buffer up a bit rather than having the callers prod at it's buffer/usage elements directly. Dave > trace_loadvm_handle_cmd_packaged_received(ret); > > - /* Setup a dummy QEMUFile that actually reads from the buffer */ > - qsb = qsb_create(buffer, length); > - g_free(buffer); /* Because qsb_create copies */ > - if (!qsb) { > - error_report("Unable to create qsb"); > - } > - QEMUFile *packf = qemu_bufopen("r", qsb); > + QEMUFile *packf = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); > > ret = qemu_loadvm_state_main(packf, mis); > trace_loadvm_handle_cmd_packaged_main(ret); > qemu_fclose(packf); > - qsb_free(qsb); > + object_unref(OBJECT(bioc)); > > return ret; > } > -- > 2.5.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Mon, Jan 25, 2016 at 07:38:59PM +0000, Dr. David Alan Gilbert wrote: > * Daniel P. Berrange (berrange@redhat.com) wrote: > > The post-copy code does some I/O to/from an intermediate > > in-memory buffer rather than direct to the underlying > > I/O channel. Switch this code to use QIOChannelBuffer > > instead of QEMUSizedBuffer. > > > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > > --- > > docs/migration.txt | 4 ++-- > > include/sysemu/sysemu.h | 2 +- > > migration/migration.c | 15 +++++++-------- > > migration/savevm.c | 41 +++++++++++++---------------------------- > > 4 files changed, 23 insertions(+), 39 deletions(-) > > > > diff --git a/docs/migration.txt b/docs/migration.txt > > index fda8d61..11703de 100644 > > --- a/docs/migration.txt > > +++ b/docs/migration.txt > > @@ -403,8 +403,8 @@ listen thread: --- page -- page -- page -- page -- page -- > > > > On receipt of CMD_PACKAGED (1) > > All the data associated with the package - the ( ... ) section in the > > -diagram - is read into memory (into a QEMUSizedBuffer), and the main thread > > -recurses into qemu_loadvm_state_main to process the contents of the package (2) > > +diagram - is read into memory, and the main thread recurses into > > +qemu_loadvm_state_main to process the contents of the package (2) > > which contains commands (3,6) and devices (4...) > > > > On receipt of 'postcopy listen' - 3 -(i.e. the 1st command in the package) > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > > index 3bb8897..0f59912 100644 > > --- a/include/sysemu/sysemu.h > > +++ b/include/sysemu/sysemu.h > > @@ -120,7 +120,7 @@ void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, > > uint16_t len, uint8_t *data); > > void qemu_savevm_send_ping(QEMUFile *f, uint32_t value); > > void qemu_savevm_send_open_return_path(QEMUFile *f); > > -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb); > > +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len); > > void qemu_savevm_send_postcopy_advise(QEMUFile *f); > > void qemu_savevm_send_postcopy_listen(QEMUFile *f); > > void qemu_savevm_send_postcopy_run(QEMUFile *f); > > diff --git a/migration/migration.c b/migration/migration.c > > index 715f069..e921b20 100644 > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -33,6 +33,7 @@ > > #include "qom/cpu.h" > > #include "exec/memory.h" > > #include "exec/address-spaces.h" > > +#include "io/channel-buffer.h" > > > > #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ > > > > @@ -1401,7 +1402,8 @@ static int await_return_path_close_on_source(MigrationState *ms) > > static int postcopy_start(MigrationState *ms, bool *old_vm_running) > > { > > int ret; > > - const QEMUSizedBuffer *qsb; > > + QIOChannelBuffer *bioc; > > + QEMUFile *fb; > > int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > > migrate_set_state(ms, MIGRATION_STATUS_ACTIVE, > > MIGRATION_STATUS_POSTCOPY_ACTIVE); > > @@ -1456,11 +1458,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) > > * So we wrap the device state up in a package with a length at the start; > > * to do this we use a qemu_buf to hold the whole of the device state. > > */ > > - QEMUFile *fb = qemu_bufopen("w", NULL); > > - if (!fb) { > > - error_report("Failed to create buffered file"); > > - goto fail; > > - } > > + bioc = qio_channel_buffer_new(4096); > > + fb = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); > > Why is that _input ? A mistake - should be output given that the old code used "w". > Also, what's your naming converntion; my 'qsb' was just an > abbreviation of (Q)EMU(S)ized(B)uffer; what's a bioc? In the vast majority of cases where you just have a pointer to the generic base class QIOChannel, then I'll use 'ioc' as the standard variable name - ie 'io' and 'c' for channel. If I have a specialized subtype, I prefix a single letter reflecting the name of the subtype. eg 's' for QIOChannelSocket giving "sioc" and 'b' for QIOChannelBuffer giving "bioc" etc. > > + object_unref(OBJECT(bioc)); > > > > /* > > * Make sure the receiver can get incoming pages before we send the rest > > @@ -1474,10 +1474,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) > > qemu_savevm_send_postcopy_run(fb); > > > > /* <><> end of stuff going into the package */ > > - qsb = qemu_buf_get(fb); > > > > /* Now send that blob */ > > - if (qemu_savevm_send_packaged(ms->file, qsb)) { > > + if (qemu_savevm_send_packaged(ms->file, bioc->data, bioc->usage)) { > > goto fail_closefb; > > } > > qemu_fclose(fb); > > diff --git a/migration/savevm.c b/migration/savevm.c > > index 0ad1b93..f2e1880 100644 > > --- a/migration/savevm.c > > +++ b/migration/savevm.c > > @@ -50,6 +50,7 @@ > > #include "qemu/iov.h" > > #include "block/snapshot.h" > > #include "block/qapi.h" > > +#include "io/channel-buffer.h" > > > > > > #ifndef ETH_P_RARP > > @@ -760,10 +761,8 @@ void qemu_savevm_send_open_return_path(QEMUFile *f) > > * 0 on success > > * -ve on error > > */ > > -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) > > +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len) > > { > > - size_t cur_iov; > > - size_t len = qsb_get_length(qsb); > > uint32_t tmp; > > > > if (len > MAX_VM_CMD_PACKAGED_SIZE) { > > @@ -777,18 +776,7 @@ int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) > > trace_qemu_savevm_send_packaged(); > > qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); > > > > - /* all the data follows (concatinating the iov's) */ > > - for (cur_iov = 0; cur_iov < qsb->n_iov; cur_iov++) { > > - /* The iov entries are partially filled */ > > - size_t towrite = MIN(qsb->iov[cur_iov].iov_len, len); > > - len -= towrite; > > - > > - if (!towrite) { > > - break; > > - } > > - > > - qemu_put_buffer(f, qsb->iov[cur_iov].iov_base, towrite); > > - } > > + qemu_put_buffer(f, (const uint8_t *)buf, len); > > > > return 0; > > } > > @@ -1548,9 +1536,8 @@ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) > > static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) > > { > > int ret; > > - uint8_t *buffer; > > uint32_t length; > > - QEMUSizedBuffer *qsb; > > + QIOChannelBuffer *bioc; > > > > length = qemu_get_be32(mis->from_src_file); > > trace_loadvm_handle_cmd_packaged(length); > > @@ -1559,28 +1546,26 @@ static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) > > error_report("Unreasonably large packaged state: %u", length); > > return -1; > > } > > - buffer = g_malloc0(length); > > - ret = qemu_get_buffer(mis->from_src_file, buffer, (int)length); > > + > > + bioc = qio_channel_buffer_new(length); > > + ret = qemu_get_buffer(mis->from_src_file, > > + (uint8_t *)bioc->data, > > + (int)length); > > Actually, qemu_get_buffer takes a size_t now; so you can fix that at the same time. Great. > > > if (ret != length) { > > - g_free(buffer); > > + object_unref(OBJECT(bioc)); > > error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%d\n", > > ret, length); > > return (ret < 0) ? ret : -EAGAIN; > > } > > + bioc->usage += length; > > I'm a bit surprised you've not wrapped feeding the data > into the qio_channel_buffer up a bit rather than having the callers > prod at it's buffer/usage elements directly. I figured it was better to avoid extra memcpy's in the migration code, so decided to directly pass the internal buffer to get_qemu_buffer(). Regards, Daniel
* Daniel P. Berrange (berrange@redhat.com) wrote: > On Mon, Jan 25, 2016 at 07:38:59PM +0000, Dr. David Alan Gilbert wrote: > > * Daniel P. Berrange (berrange@redhat.com) wrote: > > > The post-copy code does some I/O to/from an intermediate > > > in-memory buffer rather than direct to the underlying > > > I/O channel. Switch this code to use QIOChannelBuffer > > > instead of QEMUSizedBuffer. > > > > > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > > > --- > > > docs/migration.txt | 4 ++-- > > > include/sysemu/sysemu.h | 2 +- > > > migration/migration.c | 15 +++++++-------- > > > migration/savevm.c | 41 +++++++++++++---------------------------- > > > 4 files changed, 23 insertions(+), 39 deletions(-) > > > > > > diff --git a/docs/migration.txt b/docs/migration.txt > > > index fda8d61..11703de 100644 > > > --- a/docs/migration.txt > > > +++ b/docs/migration.txt > > > @@ -403,8 +403,8 @@ listen thread: --- page -- page -- page -- page -- page -- > > > > > > On receipt of CMD_PACKAGED (1) > > > All the data associated with the package - the ( ... ) section in the > > > -diagram - is read into memory (into a QEMUSizedBuffer), and the main thread > > > -recurses into qemu_loadvm_state_main to process the contents of the package (2) > > > +diagram - is read into memory, and the main thread recurses into > > > +qemu_loadvm_state_main to process the contents of the package (2) > > > which contains commands (3,6) and devices (4...) > > > > > > On receipt of 'postcopy listen' - 3 -(i.e. the 1st command in the package) > > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > > > index 3bb8897..0f59912 100644 > > > --- a/include/sysemu/sysemu.h > > > +++ b/include/sysemu/sysemu.h > > > @@ -120,7 +120,7 @@ void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, > > > uint16_t len, uint8_t *data); > > > void qemu_savevm_send_ping(QEMUFile *f, uint32_t value); > > > void qemu_savevm_send_open_return_path(QEMUFile *f); > > > -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb); > > > +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len); > > > void qemu_savevm_send_postcopy_advise(QEMUFile *f); > > > void qemu_savevm_send_postcopy_listen(QEMUFile *f); > > > void qemu_savevm_send_postcopy_run(QEMUFile *f); > > > diff --git a/migration/migration.c b/migration/migration.c > > > index 715f069..e921b20 100644 > > > --- a/migration/migration.c > > > +++ b/migration/migration.c > > > @@ -33,6 +33,7 @@ > > > #include "qom/cpu.h" > > > #include "exec/memory.h" > > > #include "exec/address-spaces.h" > > > +#include "io/channel-buffer.h" > > > > > > #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ > > > > > > @@ -1401,7 +1402,8 @@ static int await_return_path_close_on_source(MigrationState *ms) > > > static int postcopy_start(MigrationState *ms, bool *old_vm_running) > > > { > > > int ret; > > > - const QEMUSizedBuffer *qsb; > > > + QIOChannelBuffer *bioc; > > > + QEMUFile *fb; > > > int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > > > migrate_set_state(ms, MIGRATION_STATUS_ACTIVE, > > > MIGRATION_STATUS_POSTCOPY_ACTIVE); > > > @@ -1456,11 +1458,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) > > > * So we wrap the device state up in a package with a length at the start; > > > * to do this we use a qemu_buf to hold the whole of the device state. > > > */ > > > - QEMUFile *fb = qemu_bufopen("w", NULL); > > > - if (!fb) { > > > - error_report("Failed to create buffered file"); > > > - goto fail; > > > - } > > > + bioc = qio_channel_buffer_new(4096); > > > + fb = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); > > > > Why is that _input ? > > A mistake - should be output given that the old code used "w". OK, that makes sense then. > > Also, what's your naming converntion; my 'qsb' was just an > > abbreviation of (Q)EMU(S)ized(B)uffer; what's a bioc? > > In the vast majority of cases where you just have a pointer > to the generic base class QIOChannel, then I'll use 'ioc' as > the standard variable name - ie 'io' and 'c' for channel. > > If I have a specialized subtype, I prefix a single letter > reflecting the name of the subtype. eg 's' for QIOChannelSocket > giving "sioc" and 'b' for QIOChannelBuffer giving "bioc" etc. OK, my preference there would have been iocb just because it's the same order as the thing it's abbreviating; but that's just a personal preference. > > > + object_unref(OBJECT(bioc)); > > > > > > /* > > > * Make sure the receiver can get incoming pages before we send the rest > > > @@ -1474,10 +1474,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) > > > qemu_savevm_send_postcopy_run(fb); > > > > > > /* <><> end of stuff going into the package */ > > > - qsb = qemu_buf_get(fb); > > > > > > /* Now send that blob */ > > > - if (qemu_savevm_send_packaged(ms->file, qsb)) { > > > + if (qemu_savevm_send_packaged(ms->file, bioc->data, bioc->usage)) { > > > goto fail_closefb; > > > } > > > qemu_fclose(fb); > > > diff --git a/migration/savevm.c b/migration/savevm.c > > > index 0ad1b93..f2e1880 100644 > > > --- a/migration/savevm.c > > > +++ b/migration/savevm.c > > > @@ -50,6 +50,7 @@ > > > #include "qemu/iov.h" > > > #include "block/snapshot.h" > > > #include "block/qapi.h" > > > +#include "io/channel-buffer.h" > > > > > > > > > #ifndef ETH_P_RARP > > > @@ -760,10 +761,8 @@ void qemu_savevm_send_open_return_path(QEMUFile *f) > > > * 0 on success > > > * -ve on error > > > */ > > > -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) > > > +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len) > > > { > > > - size_t cur_iov; > > > - size_t len = qsb_get_length(qsb); > > > uint32_t tmp; > > > > > > if (len > MAX_VM_CMD_PACKAGED_SIZE) { > > > @@ -777,18 +776,7 @@ int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) > > > trace_qemu_savevm_send_packaged(); > > > qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); > > > > > > - /* all the data follows (concatinating the iov's) */ > > > - for (cur_iov = 0; cur_iov < qsb->n_iov; cur_iov++) { > > > - /* The iov entries are partially filled */ > > > - size_t towrite = MIN(qsb->iov[cur_iov].iov_len, len); > > > - len -= towrite; > > > - > > > - if (!towrite) { > > > - break; > > > - } > > > - > > > - qemu_put_buffer(f, qsb->iov[cur_iov].iov_base, towrite); > > > - } > > > + qemu_put_buffer(f, (const uint8_t *)buf, len); > > > > > > return 0; > > > } > > > @@ -1548,9 +1536,8 @@ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) > > > static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) > > > { > > > int ret; > > > - uint8_t *buffer; > > > uint32_t length; > > > - QEMUSizedBuffer *qsb; > > > + QIOChannelBuffer *bioc; > > > > > > length = qemu_get_be32(mis->from_src_file); > > > trace_loadvm_handle_cmd_packaged(length); > > > @@ -1559,28 +1546,26 @@ static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) > > > error_report("Unreasonably large packaged state: %u", length); > > > return -1; > > > } > > > - buffer = g_malloc0(length); > > > - ret = qemu_get_buffer(mis->from_src_file, buffer, (int)length); > > > + > > > + bioc = qio_channel_buffer_new(length); > > > + ret = qemu_get_buffer(mis->from_src_file, > > > + (uint8_t *)bioc->data, > > > + (int)length); > > > > Actually, qemu_get_buffer takes a size_t now; so you can fix that at the same time. > > Great. > > > > > > if (ret != length) { > > > - g_free(buffer); > > > + object_unref(OBJECT(bioc)); > > > error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%d\n", > > > ret, length); > > > return (ret < 0) ? ret : -EAGAIN; > > > } > > > + bioc->usage += length; > > > > I'm a bit surprised you've not wrapped feeding the data > > into the qio_channel_buffer up a bit rather than having the callers > > prod at it's buffer/usage elements directly. > > I figured it was better to avoid extra memcpy's in the migration code, > so decided to directly pass the internal buffer to get_qemu_buffer(). Yes, avoiding copies is good; I was just thinking more of a function that incremented the usage or something like that. Dave > > > Regards, > Daniel > -- > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/docs/migration.txt b/docs/migration.txt index fda8d61..11703de 100644 --- a/docs/migration.txt +++ b/docs/migration.txt @@ -403,8 +403,8 @@ listen thread: --- page -- page -- page -- page -- page -- On receipt of CMD_PACKAGED (1) All the data associated with the package - the ( ... ) section in the -diagram - is read into memory (into a QEMUSizedBuffer), and the main thread -recurses into qemu_loadvm_state_main to process the contents of the package (2) +diagram - is read into memory, and the main thread recurses into +qemu_loadvm_state_main to process the contents of the package (2) which contains commands (3,6) and devices (4...) On receipt of 'postcopy listen' - 3 -(i.e. the 1st command in the package) diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index 3bb8897..0f59912 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -120,7 +120,7 @@ void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, uint16_t len, uint8_t *data); void qemu_savevm_send_ping(QEMUFile *f, uint32_t value); void qemu_savevm_send_open_return_path(QEMUFile *f); -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb); +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len); void qemu_savevm_send_postcopy_advise(QEMUFile *f); void qemu_savevm_send_postcopy_listen(QEMUFile *f); void qemu_savevm_send_postcopy_run(QEMUFile *f); diff --git a/migration/migration.c b/migration/migration.c index 715f069..e921b20 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -33,6 +33,7 @@ #include "qom/cpu.h" #include "exec/memory.h" #include "exec/address-spaces.h" +#include "io/channel-buffer.h" #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ @@ -1401,7 +1402,8 @@ static int await_return_path_close_on_source(MigrationState *ms) static int postcopy_start(MigrationState *ms, bool *old_vm_running) { int ret; - const QEMUSizedBuffer *qsb; + QIOChannelBuffer *bioc; + QEMUFile *fb; int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); migrate_set_state(ms, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_POSTCOPY_ACTIVE); @@ -1456,11 +1458,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) * So we wrap the device state up in a package with a length at the start; * to do this we use a qemu_buf to hold the whole of the device state. */ - QEMUFile *fb = qemu_bufopen("w", NULL); - if (!fb) { - error_report("Failed to create buffered file"); - goto fail; - } + bioc = qio_channel_buffer_new(4096); + fb = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); + object_unref(OBJECT(bioc)); /* * Make sure the receiver can get incoming pages before we send the rest @@ -1474,10 +1474,9 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) qemu_savevm_send_postcopy_run(fb); /* <><> end of stuff going into the package */ - qsb = qemu_buf_get(fb); /* Now send that blob */ - if (qemu_savevm_send_packaged(ms->file, qsb)) { + if (qemu_savevm_send_packaged(ms->file, bioc->data, bioc->usage)) { goto fail_closefb; } qemu_fclose(fb); diff --git a/migration/savevm.c b/migration/savevm.c index 0ad1b93..f2e1880 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -50,6 +50,7 @@ #include "qemu/iov.h" #include "block/snapshot.h" #include "block/qapi.h" +#include "io/channel-buffer.h" #ifndef ETH_P_RARP @@ -760,10 +761,8 @@ void qemu_savevm_send_open_return_path(QEMUFile *f) * 0 on success * -ve on error */ -int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) +int qemu_savevm_send_packaged(QEMUFile *f, const char *buf, size_t len) { - size_t cur_iov; - size_t len = qsb_get_length(qsb); uint32_t tmp; if (len > MAX_VM_CMD_PACKAGED_SIZE) { @@ -777,18 +776,7 @@ int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb) trace_qemu_savevm_send_packaged(); qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); - /* all the data follows (concatinating the iov's) */ - for (cur_iov = 0; cur_iov < qsb->n_iov; cur_iov++) { - /* The iov entries are partially filled */ - size_t towrite = MIN(qsb->iov[cur_iov].iov_len, len); - len -= towrite; - - if (!towrite) { - break; - } - - qemu_put_buffer(f, qsb->iov[cur_iov].iov_base, towrite); - } + qemu_put_buffer(f, (const uint8_t *)buf, len); return 0; } @@ -1548,9 +1536,8 @@ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) { int ret; - uint8_t *buffer; uint32_t length; - QEMUSizedBuffer *qsb; + QIOChannelBuffer *bioc; length = qemu_get_be32(mis->from_src_file); trace_loadvm_handle_cmd_packaged(length); @@ -1559,28 +1546,26 @@ static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) error_report("Unreasonably large packaged state: %u", length); return -1; } - buffer = g_malloc0(length); - ret = qemu_get_buffer(mis->from_src_file, buffer, (int)length); + + bioc = qio_channel_buffer_new(length); + ret = qemu_get_buffer(mis->from_src_file, + (uint8_t *)bioc->data, + (int)length); if (ret != length) { - g_free(buffer); + object_unref(OBJECT(bioc)); error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%d\n", ret, length); return (ret < 0) ? ret : -EAGAIN; } + bioc->usage += length; trace_loadvm_handle_cmd_packaged_received(ret); - /* Setup a dummy QEMUFile that actually reads from the buffer */ - qsb = qsb_create(buffer, length); - g_free(buffer); /* Because qsb_create copies */ - if (!qsb) { - error_report("Unable to create qsb"); - } - QEMUFile *packf = qemu_bufopen("r", qsb); + QEMUFile *packf = qemu_fopen_channel_input(QIO_CHANNEL(bioc)); ret = qemu_loadvm_state_main(packf, mis); trace_loadvm_handle_cmd_packaged_main(ret); qemu_fclose(packf); - qsb_free(qsb); + object_unref(OBJECT(bioc)); return ret; }
The post-copy code does some I/O to/from an intermediate in-memory buffer rather than direct to the underlying I/O channel. Switch this code to use QIOChannelBuffer instead of QEMUSizedBuffer. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- docs/migration.txt | 4 ++-- include/sysemu/sysemu.h | 2 +- migration/migration.c | 15 +++++++-------- migration/savevm.c | 41 +++++++++++++---------------------------- 4 files changed, 23 insertions(+), 39 deletions(-)