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dm vdo indexer: reorder uds_request to reduce padding

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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@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
This commit is contained in:
Ken Raeburn 2025-02-24 16:36:03 -05:00 committed by Mikulas Patocka
parent 88f7f56d16
commit e678900df2
2 changed files with 27 additions and 32 deletions
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6
drivers/md/dm-vdo/indexer/index-session.c
View File

@ -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)

53
drivers/md/dm-vdo/indexer/indexer.h
View File

@ -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. */