target: Shrink struct se_cmd by rearranging fields

On x86-64, these changes reduce the struct size from 528 bytes to 496
bytes.  We save a cacheline and get under 512 bytes for better packing.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Acked-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 3afd8db..ac9bf1c 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -439,6 +439,9 @@ struct se_cmd {
        u8                      scsi_asc;
        u8                      scsi_ascq;
        u16                     scsi_sense_length;
+       unsigned                cmd_wait_set:1;
+       unsigned                unknown_data_length:1;
+       bool                    state_active:1;
        u64                     tag; /* SAM command identifier aka task tag */
        /* Delay for ALUA Active/NonOptimized state access in milliseconds */
        int                     alua_nonop_delay;
@@ -450,8 +453,6 @@ struct se_cmd {
        unsigned int            map_tag;
        /* Transport protocol dependent state, see transport_state_table */
        enum transport_state_table t_state;
-       unsigned                cmd_wait_set:1;
-       unsigned                unknown_data_length:1;
        /* See se_cmd_flags_table */
        u32                     se_cmd_flags;
        /* Total size in bytes associated with command */
@@ -471,7 +472,6 @@ struct se_cmd {
        struct se_tmr_req       *se_tmr_req;
        struct list_head        se_cmd_list;
        struct completion       cmd_wait_comp;
-       struct kref             cmd_kref;
        const struct target_core_fabric_ops *se_tfo;
        sense_reason_t          (*execute_cmd)(struct se_cmd *);
        sense_reason_t (*transport_complete_callback)(struct se_cmd *, bool);
@@ -491,6 +491,7 @@ struct se_cmd {
 #define CMD_T_REQUEST_STOP     (1 << 8)
 #define CMD_T_BUSY             (1 << 9)
        spinlock_t              t_state_lock;
+       struct kref             cmd_kref;
        struct completion       t_transport_stop_comp;
 
        struct work_struct      work;
@@ -503,8 +504,10 @@ struct se_cmd {
        struct scatterlist      *t_bidi_data_sg;
        unsigned int            t_bidi_data_nents;
 
+       /* Used for lun->lun_ref counting */
+       int                     lun_ref_active;
+
        struct list_head        state_list;
-       bool                    state_active;
 
        /* old task stop completion, consider merging with some of the above */
        struct completion       task_stop_comp;
@@ -512,20 +515,17 @@ struct se_cmd {
        /* backend private data */
        void                    *priv;
 
-       /* Used for lun->lun_ref counting */
-       int                     lun_ref_active;
-
        /* DIF related members */
        enum target_prot_op     prot_op;
        enum target_prot_type   prot_type;
        u8                      prot_checks;
+       bool                    prot_pto;
        u32                     prot_length;
        u32                     reftag_seed;
        struct scatterlist      *t_prot_sg;
        unsigned int            t_prot_nents;
        sense_reason_t          pi_err;
        sector_t                bad_sector;
-       bool                    prot_pto;
 };
 
 struct se_ua {