On Thu, Apr 25, 2024 at 02:21:13AM +0000, Hao Xiang wrote:
> Multifd sender path gets an array of pages queued by the migration
> thread. It performs zero page checking on every page in the array.
> The pages are classfied as either a zero page or a normal page. This
> change uses Intel DSA to offload the zero page checking from CPU to
> the DSA accelerator. The sender thread submits a batch of pages to DSA
> hardware and waits for the DSA completion thread to signal for work
> completion.
>
> Signed-off-by: Hao Xiang <hao.xi...@linux.dev>
> ---
> migration/multifd-zero-page.c | 99 +++++++++++++++++++++++++++++++++--
> migration/multifd.c | 27 +++++++++-
> migration/multifd.h | 1 +
> 3 files changed, 120 insertions(+), 7 deletions(-)
>
> diff --git a/migration/multifd-zero-page.c b/migration/multifd-zero-page.c
> index e1b8370f88..4f426289e4 100644
> --- a/migration/multifd-zero-page.c
> +++ b/migration/multifd-zero-page.c
> diff --git a/migration/multifd.c b/migration/multifd.c
> index cfd3a92f6c..7316643d0a 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -818,6 +818,8 @@ void multifd_send_shutdown(void)
>
> multifd_send_terminate_threads();
>
> + dsa_cleanup();
> +
> for (i = 0; i < migrate_multifd_channels(); i++) {
> MultiFDSendParams *p = &multifd_send_state->params[i];
> Error *local_err = NULL;
> @@ -1155,11 +1157,20 @@ bool multifd_send_setup(void)
> uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
> bool use_packets = multifd_use_packets();
> uint8_t i;
> + const char *dsa_parameter = migrate_multifd_dsa_accel();
>
> if (!migrate_multifd()) {
> return true;
> }
>
> + if (dsa_init(dsa_parameter)) {
> + error_setg(&local_err, "multifd: Sender failed to initialize DSA.");
> + error_report_err(local_err);
> + return false;
> + }
This is an example of why all the dsa functions need to report
a via an "Error **err" parameter. The error reported
here is useless as it lacks any meaningful information of what
went wrong.
The multifd_send_setup method itself needs a "Error **errp"
param so it can pass it back up to be reoprted too.
> +
> + dsa_start();
> +
> thread_count = migrate_multifd_channels();
> multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
> multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
> @@ -1393,6 +1404,7 @@ void multifd_recv_cleanup(void)
> qemu_thread_join(&p->thread);
> }
> }
> + dsa_cleanup();
> for (i = 0; i < migrate_multifd_channels(); i++) {
> multifd_recv_cleanup_channel(&multifd_recv_state->params[i]);
> }
> @@ -1568,6 +1580,9 @@ int multifd_recv_setup(Error **errp)
> uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
> bool use_packets = multifd_use_packets();
> uint8_t i;
> + const char *dsa_parameter = migrate_multifd_dsa_accel();
> + int ret;
> + Error *local_err = NULL;
>
> /*
> * Return successfully if multiFD recv state is already initialised
> @@ -1577,6 +1592,15 @@ int multifd_recv_setup(Error **errp)
> return 0;
> }
>
> + ret = dsa_init(dsa_parameter);
> + if (ret != 0) {
> + error_setg(&local_err, "multifd: Receiver failed to initialize
> DSA.");
> + error_propagate(errp, local_err);
> + return ret;
> + }
> +
> + dsa_start();
> +
> thread_count = migrate_multifd_channels();
> multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
> multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
> @@ -1616,13 +1640,12 @@ int multifd_recv_setup(Error **errp)
>
> for (i = 0; i < thread_count; i++) {
> MultiFDRecvParams *p = &multifd_recv_state->params[i];
> - int ret;
> -
> ret = multifd_recv_state->ops->recv_setup(p, errp);
> if (ret) {
> return ret;
> }
> }
> +
> return 0;
> }
>
> diff --git a/migration/multifd.h b/migration/multifd.h
> index 16e27db5e9..b3717fae24 100644
> --- a/migration/multifd.h
> +++ b/migration/multifd.h
> @@ -14,6 +14,7 @@
> #define QEMU_MIGRATION_MULTIFD_H
>
> #include "ram.h"
> +#include "qemu/dsa.h"
>
> typedef struct MultiFDRecvData MultiFDRecvData;
>
> --
> 2.30.2
>
>
With regards,
Daniel
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