| Message ID | 20250207184212.20831-4-dongli.zhang@oracle.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | vhost-scsi: log write descriptors for live migration (and two bugfix) | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On 2/7/25 12:41 PM, Dongli Zhang wrote: > The vhost-scsi I/O queue uses vhost_scsi_cmd. Pre-allocate the log buffer > during vhost_scsi_cmd allocation, and free it when vhost_scsi_cmd is > reclaimed. > > The cached log buffer will be uses in upcoming patches to log write > descriptors for the I/O queue. The core idea is to cache the log in the > per-command log buffer in the submission path, and use them to log write > descriptors in the completion path. > > Suggested-by: Joao Martins <joao.m.martins@oracle.com> > Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> > --- > drivers/vhost/scsi.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c > index ee2310555740..5e6221cbbe9e 100644 > --- a/drivers/vhost/scsi.c > +++ b/drivers/vhost/scsi.c > @@ -98,6 +98,11 @@ struct vhost_scsi_cmd { > unsigned char tvc_cdb[VHOST_SCSI_MAX_CDB_SIZE]; > /* Sense buffer that will be mapped into outgoing status */ > unsigned char tvc_sense_buf[TRANSPORT_SENSE_BUFFER]; > + /* > + * Dirty write descriptors of this command. > + */ > + struct vhost_log *tvc_log; > + unsigned int tvc_log_num; > /* Completed commands list, serviced from vhost worker thread */ > struct llist_node tvc_completion_list; > /* Used to track inflight cmd */ > @@ -619,6 +624,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, > struct vhost_scsi_nexus *tv_nexus; > struct scatterlist *sg, *prot_sg; > struct iovec *tvc_resp_iov; > + struct vhost_log *log; > struct page **pages; > int tag; > > @@ -639,6 +645,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, > prot_sg = cmd->tvc_prot_sgl; > pages = cmd->tvc_upages; > tvc_resp_iov = cmd->tvc_resp_iov; > + log = cmd->tvc_log; > memset(cmd, 0, sizeof(*cmd)); > cmd->tvc_sgl = sg; > cmd->tvc_prot_sgl = prot_sg; > @@ -652,6 +659,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, > cmd->tvc_nexus = tv_nexus; > cmd->inflight = vhost_scsi_get_inflight(vq); > cmd->tvc_resp_iov = tvc_resp_iov; > + cmd->tvc_log = log; > > memcpy(cmd->tvc_cdb, cdb, VHOST_SCSI_MAX_CDB_SIZE); > > @@ -1604,6 +1612,7 @@ static void vhost_scsi_destroy_vq_cmds(struct vhost_virtqueue *vq) > kfree(tv_cmd->tvc_prot_sgl); > kfree(tv_cmd->tvc_upages); > kfree(tv_cmd->tvc_resp_iov); > + kfree(tv_cmd->tvc_log); > } > > sbitmap_free(&svq->scsi_tags); > @@ -1666,6 +1675,18 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds) > pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n"); > goto out; > } > + > + /* > + * tv_cmd->tvc_log and vq->log need to have the same max > + * length. > + */ > + tv_cmd->tvc_log = kcalloc(vq->dev->iov_limit, > + sizeof(struct vhost_log), > + GFP_KERNEL); VHOST_F_LOG_ALL is normally set when the migration starts right? I mean it's done before the initial setup when the above code is run so is it possible to do the allocation when vhost_scsi_set_features is passed VHOST_F_LOG_ALL? We then don't allocate a bunch of mem for a feature that may never be used.
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index ee2310555740..5e6221cbbe9e 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -98,6 +98,11 @@ struct vhost_scsi_cmd { unsigned char tvc_cdb[VHOST_SCSI_MAX_CDB_SIZE]; /* Sense buffer that will be mapped into outgoing status */ unsigned char tvc_sense_buf[TRANSPORT_SENSE_BUFFER]; + /* + * Dirty write descriptors of this command. + */ + struct vhost_log *tvc_log; + unsigned int tvc_log_num; /* Completed commands list, serviced from vhost worker thread */ struct llist_node tvc_completion_list; /* Used to track inflight cmd */ @@ -619,6 +624,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, struct vhost_scsi_nexus *tv_nexus; struct scatterlist *sg, *prot_sg; struct iovec *tvc_resp_iov; + struct vhost_log *log; struct page **pages; int tag; @@ -639,6 +645,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, prot_sg = cmd->tvc_prot_sgl; pages = cmd->tvc_upages; tvc_resp_iov = cmd->tvc_resp_iov; + log = cmd->tvc_log; memset(cmd, 0, sizeof(*cmd)); cmd->tvc_sgl = sg; cmd->tvc_prot_sgl = prot_sg; @@ -652,6 +659,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, cmd->tvc_nexus = tv_nexus; cmd->inflight = vhost_scsi_get_inflight(vq); cmd->tvc_resp_iov = tvc_resp_iov; + cmd->tvc_log = log; memcpy(cmd->tvc_cdb, cdb, VHOST_SCSI_MAX_CDB_SIZE); @@ -1604,6 +1612,7 @@ static void vhost_scsi_destroy_vq_cmds(struct vhost_virtqueue *vq) kfree(tv_cmd->tvc_prot_sgl); kfree(tv_cmd->tvc_upages); kfree(tv_cmd->tvc_resp_iov); + kfree(tv_cmd->tvc_log); } sbitmap_free(&svq->scsi_tags); @@ -1666,6 +1675,18 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds) pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n"); goto out; } + + /* + * tv_cmd->tvc_log and vq->log need to have the same max + * length. + */ + tv_cmd->tvc_log = kcalloc(vq->dev->iov_limit, + sizeof(struct vhost_log), + GFP_KERNEL); + if (!tv_cmd->tvc_log) { + pr_err("Unable to allocate tv_cmd->tvc_log\n"); + goto out; + } } return 0; out:
The vhost-scsi I/O queue uses vhost_scsi_cmd. Pre-allocate the log buffer during vhost_scsi_cmd allocation, and free it when vhost_scsi_cmd is reclaimed. The cached log buffer will be uses in upcoming patches to log write descriptors for the I/O queue. The core idea is to cache the log in the per-command log buffer in the submission path, and use them to log write descriptors in the completion path. Suggested-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> --- drivers/vhost/scsi.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)