From 61e68b3fbd3e2b7beb636bc56f78d9c1ca25e8f9 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Tue, 16 Sep 2014 15:20:17 +0800 Subject: scsi: Optimize scsi_req_alloc Zeroing sense buffer for each scsi request is not efficient, we can just leave it uninitialized because sense_len is set to 0. Move the implicitly zeroed fields to the end of the structure and use a partial memset. The explicitly initialized fields (by scsi_req_alloc or scsi_req_new) are moved to the beginning of the structure, before sense buffer, to skip the memset. Also change g_malloc0 to g_slice_alloc. Signed-off-by: Fam Zheng Signed-off-by: Paolo Bonzini --- include/hw/scsi/scsi.h | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'include/hw/scsi') diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h index 2e3a8f987d..6271ad3034 100644 --- a/include/hw/scsi/scsi.h +++ b/include/hw/scsi/scsi.h @@ -50,17 +50,24 @@ struct SCSIRequest { uint32_t tag; uint32_t lun; uint32_t status; + void *hba_private; size_t resid; SCSICommand cmd; + + /* Note: + * - fields before sense are initialized by scsi_req_alloc; + * - sense[] is uninitialized; + * - fields after sense are memset to 0 by scsi_req_alloc. + * */ + + uint8_t sense[SCSI_SENSE_BUF_SIZE]; + uint32_t sense_len; + bool enqueued; + bool io_canceled; + bool retry; + bool dma_started; BlockDriverAIOCB *aiocb; QEMUSGList *sg; - bool dma_started; - uint8_t sense[SCSI_SENSE_BUF_SIZE]; - uint32_t sense_len; - bool enqueued; - bool io_canceled; - bool retry; - void *hba_private; QTAILQ_ENTRY(SCSIRequest) next; }; -- cgit v1.2.3