From: Ken Raeburn <raeburn@xxxxxxxxxx>
Reorder fields and make uds_request_type and uds_zone_message packed,
to squeeze out some space. Use struct_group so the request reset code
no longer needs to care about field order.
On x86_64 this reduces the struct size from 144 to 120, which saves 48
kB (about 12%) per VDO hash zone.
Signed-off-by: Ken Raeburn <raeburn@xxxxxxxxxx>
Signed-off-by: Matthew Sakai <msakai@xxxxxxxxxx>
---
drivers/md/dm-vdo/indexer/index-session.c | 6 +--
drivers/md/dm-vdo/indexer/indexer.h | 53 +++++++++++------------
2 files changed, 27 insertions(+), 32 deletions(-)
diff --git a/drivers/md/dm-vdo/indexer/index-session.c b/drivers/md/dm-vdo/indexer/index-session.c
index aee0914d604a..aa575a24e0b2 100644
--- a/drivers/md/dm-vdo/indexer/index-session.c
+++ b/drivers/md/dm-vdo/indexer/index-session.c
@@ -100,7 +100,6 @@ static int get_index_session(struct uds_index_session *index_session)
int uds_launch_request(struct uds_request *request)
{
- size_t internal_size;
int result;
if (request->callback == NULL) {
@@ -121,10 +120,7 @@ int uds_launch_request(struct uds_request *request)
}
/* Reset all internal fields before processing. */
- internal_size =
- sizeof(struct uds_request) - offsetof(struct uds_request, zone_number);
- // FIXME should be using struct_group for this instead
- memset((char *) request + sizeof(*request) - internal_size, 0, internal_size);
+ memset(&request->internal, 0, sizeof(request->internal));
result = get_index_session(request->session);
if (result != UDS_SUCCESS)
diff --git a/drivers/md/dm-vdo/indexer/indexer.h b/drivers/md/dm-vdo/indexer/indexer.h
index 3744aaf625b0..d765f24328eb 100644
--- a/drivers/md/dm-vdo/indexer/indexer.h
+++ b/drivers/md/dm-vdo/indexer/indexer.h
@@ -8,6 +8,7 @@
#include <linux/mutex.h>
#include <linux/sched.h>
+#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/wait.h>
@@ -73,7 +74,7 @@ enum uds_request_type {
/* Remove any mapping for a name. */
UDS_DELETE,
-};
+} __packed;
enum uds_open_index_type {
/* Create a new index. */
@@ -226,7 +227,7 @@ struct uds_zone_message {
enum uds_zone_message_type type;
/* The virtual chapter number to which the message applies */
u64 virtual_chapter;
-};
+} __packed;
struct uds_index_session;
struct uds_index;
@@ -253,34 +254,32 @@ struct uds_request {
/* The existing data associated with the request name, if any */
struct uds_record_data old_metadata;
- /* Either UDS_SUCCESS or an error code for the request */
- int status;
/* True if the record name had an existing entry in the index */
bool found;
+ /* Either UDS_SUCCESS or an error code for the request */
+ int status;
- /*
- * The remaining fields are used internally and should not be altered by clients. The index
- * relies on zone_number being the first field in this section.
- */
-
- /* The number of the zone which will process this request*/
- unsigned int zone_number;
- /* A link for adding a request to a lock-free queue */
- struct funnel_queue_entry queue_link;
- /* A link for adding a request to a standard linked list */
- struct uds_request *next_request;
- /* A pointer to the index processing this request */
- struct uds_index *index;
- /* Control message for coordinating between zones */
- struct uds_zone_message zone_message;
- /* If true, process request immediately by waking the worker thread */
- bool unbatched;
- /* If true, continue this request before processing newer requests */
- bool requeued;
- /* The virtual chapter containing the record name, if known */
- u64 virtual_chapter;
- /* The region of the index containing the record name */
- enum uds_index_region location;
+ /* The remaining fields are used internally and should not be altered by clients. */
+ struct_group(internal,
+ /* The virtual chapter containing the record name, if known */
+ u64 virtual_chapter;
+ /* The region of the index containing the record name */
+ enum uds_index_region location;
+ /* If true, process request immediately by waking the worker thread */
+ bool unbatched;
+ /* If true, continue this request before processing newer requests */
+ bool requeued;
+ /* Control message for coordinating between zones */
+ struct uds_zone_message zone_message;
+ /* The number of the zone which will process this request*/
+ unsigned int zone_number;
+ /* A link for adding a request to a lock-free queue */
+ struct funnel_queue_entry queue_link;
+ /* A link for adding a request to a standard linked list */
+ struct uds_request *next_request;
+ /* A pointer to the index processing this request */
+ struct uds_index *index;
+ );
};
/* A session is required for most index operations. */
--
2.45.2
