On 21/04/2020 13:49, Ming Lei wrote:
The following three fields of scsi_host_template are referenced in
scsi IO submission path, so put them together into one cacheline:
- cmd_size
- queuecommand
- commit_rqs
Cc: Bart Van Assche <bvanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: John Garry <john.garry@xxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
include/scsi/scsi_host.h | 67 +++++++++++++++++++++-------------------
1 file changed, 35 insertions(+), 32 deletions(-)
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 822e8cda8d9b..959dc5160f72 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -33,37 +33,12 @@ struct scsi_host_template {
struct module *module;
const char *name;
- /*
- * The info function will return whatever useful information the
- * developer sees fit. If not provided, then the name field will
- * be used instead.
- *
- * Status: OPTIONAL
- */
- const char *(* info)(struct Scsi_Host *);
+ /* Put hot fields together in same cacheline */
/*
- * Ioctl interface
- *
- * Status: OPTIONAL
- */
- int (*ioctl)(struct scsi_device *dev, unsigned int cmd,
- void __user *arg);
-
-
-#ifdef CONFIG_COMPAT
- /*
- * Compat handler. Handle 32bit ABI.
- * When unknown ioctl is passed return -ENOIOCTLCMD.
- *
- * Status: OPTIONAL
+ * Additional per-command data allocated for the driver.
*/
- int (*compat_ioctl)(struct scsi_device *dev, unsigned int cmd,
- void __user *arg);
-#endif
-
- int (*init_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
- int (*exit_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
Should new member .init_cmd_priv be included also in the "hot" group?
Even if NULL generally, we still have to load that from memory to know
it (is NULL) in scsi_mq_init_request() and scsi_init_command() [which
are fastpath, right?]
Cheers,
John
+ unsigned int cmd_size;
/*
* The queuecommand function is used to queue up a scsi
@@ -111,6 +86,38 @@ struct scsi_host_template {
*/
void (*commit_rqs)(struct Scsi_Host *, u16);
+ /*
+ * The info function will return whatever useful information the
+ * developer sees fit. If not provided, then the name field will
+ * be used instead.
+ *
+ * Status: OPTIONAL
+ */
+ const char *(* info)(struct Scsi_Host *);
+
+ /*
+ * Ioctl interface
+ *
+ * Status: OPTIONAL
+ */
+ int (*ioctl)(struct scsi_device *dev, unsigned int cmd,
+ void __user *arg);
+
+
+#ifdef CONFIG_COMPAT
+ /*
+ * Compat handler. Handle 32bit ABI.
+ * When unknown ioctl is passed return -ENOIOCTLCMD.
+ *
+ * Status: OPTIONAL
+ */
+ int (*compat_ioctl)(struct scsi_device *dev, unsigned int cmd,
+ void __user *arg);
+#endif
+
+ int (*init_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
+ int (*exit_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
+
/*
* This is an error handling strategy routine. You don't need to
* define one of these if you don't want to - there is a default
@@ -468,10 +475,6 @@ struct scsi_host_template {
*/
u64 vendor_id;
- /*
- * Additional per-command data allocated for the driver.
- */
- unsigned int cmd_size;
struct scsi_host_cmd_pool *cmd_pool;
/* Delay for runtime autosuspend */
