MFC r313910: Change XCOPY memory allocations.

Before this change XCOPY code could allocate memory in chunks up to 16-32MB
(VMware does XCOPY in 4MB chunks by default), that could be difficult for
VM subsystem to do due to KVA fragmentation, that sometimes created huge
allocation delays, blocking any I/O for respective LU for that time.

This change limits allocations down to TPC_MAX_IO_SIZE, which is 1MB now.
1MB is also not a cookie, but ZFS also can do that for large blocks, so
it should be less dramatic.  As drawback this increases CPU overhead, but
it still look acceptable comparing to time consumed by ZFS read/write.

1 files changed, 12 insertions, 13 deletions

diff --git a/sys/cam/ctl/ctl_tpc.c b/sys/cam/ctl/ctl_tpc.c
index c8d60ca..39d4f24 100644
--- a/sys/cam/ctl/ctl_tpc.c
+++ b/sys/cam/ctl/ctl_tpc.c
@@ -85,6 +85,7 @@ struct tpc_io {
 	uint8_t			 target;
 	uint32_t		 cscd;
 	uint64_t		 lun;
+	uint8_t			*buf;
 	struct tpc_list		*list;
 	struct runl		 run;
 	TAILQ_ENTRY(tpc_io)	 rlinks;
@@ -127,7 +128,6 @@ struct tpc_list {
 	off_t			 curbytes;
 	int			 curops;
 	int			 stage;
-	uint8_t			*buf;
 	off_t			 segsectors;
 	off_t			 segbytes;
 	int			 tbdio;
@@ -813,9 +813,9 @@ tpc_process_b2b(struct tpc_list *list)
 		while ((tior = TAILQ_FIRST(&list->allio)) != NULL) {
 			TAILQ_REMOVE(&list->allio, tior, links);
 			ctl_free_io(tior->io);
+			free(tior->buf, M_CTL);
 			free(tior, M_CTL);
 		}
-		free(list->buf, M_CTL);
 		if (list->abort) {
 			ctl_set_task_aborted(list->ctsio);
 			return (CTL_RETVAL_ERROR);
@@ -874,7 +874,6 @@ tpc_process_b2b(struct tpc_list *list)
 		return (CTL_RETVAL_ERROR);
 	}
 
-	list->buf = malloc(numbytes, M_CTL, M_WAITOK);
 	list->segbytes = numbytes;
 	list->segsectors = numbytes / dstblock;
 	donebytes = 0;
@@ -894,11 +893,12 @@ tpc_process_b2b(struct tpc_list *list)
 
 		tior = malloc(sizeof(*tior), M_CTL, M_WAITOK | M_ZERO);
 		TAILQ_INIT(&tior->run);
+		tior->buf = malloc(roundbytes, M_CTL, M_WAITOK);
 		tior->list = list;
 		TAILQ_INSERT_TAIL(&list->allio, tior, links);
 		tior->io = tpcl_alloc_io();
 		ctl_scsi_read_write(tior->io,
-				    /*data_ptr*/ &list->buf[donebytes],
+				    /*data_ptr*/ tior->buf,
 				    /*data_len*/ roundbytes,
 				    /*read_op*/ 1,
 				    /*byte2*/ 0,
@@ -919,7 +919,7 @@ tpc_process_b2b(struct tpc_list *list)
 		TAILQ_INSERT_TAIL(&list->allio, tiow, links);
 		tiow->io = tpcl_alloc_io();
 		ctl_scsi_read_write(tiow->io,
-				    /*data_ptr*/ &list->buf[donebytes],
+				    /*data_ptr*/ tior->buf,
 				    /*data_len*/ roundbytes,
 				    /*read_op*/ 0,
 				    /*byte2*/ 0,
@@ -1029,9 +1029,9 @@ tpc_process_register_key(struct tpc_list *list)
 		while ((tio = TAILQ_FIRST(&list->allio)) != NULL) {
 			TAILQ_REMOVE(&list->allio, tio, links);
 			ctl_free_io(tio->io);
+			free(tio->buf, M_CTL);
 			free(tio, M_CTL);
 		}
-		free(list->buf, M_CTL);
 		if (list->abort) {
 			ctl_set_task_aborted(list->ctsio);
 			return (CTL_RETVAL_ERROR);
@@ -1064,9 +1064,9 @@ tpc_process_register_key(struct tpc_list *list)
 	TAILQ_INSERT_TAIL(&list->allio, tio, links);
 	tio->io = tpcl_alloc_io();
 	datalen = sizeof(struct scsi_per_res_out_parms);
-	list->buf = malloc(datalen, M_CTL, M_WAITOK);
+	tio->buf = malloc(datalen, M_CTL, M_WAITOK);
 	ctl_scsi_persistent_res_out(tio->io,
-	    list->buf, datalen, SPRO_REGISTER, -1,
+	    tio->buf, datalen, SPRO_REGISTER, -1,
 	    scsi_8btou64(seg->res_key), scsi_8btou64(seg->sa_res_key),
 	    /*tag_type*/ CTL_TAG_SIMPLE, /*control*/ 0);
 	tio->io->io_hdr.retries = 3;
@@ -1166,9 +1166,9 @@ tpc_process_wut(struct tpc_list *list)
 		while ((tio = TAILQ_FIRST(&list->allio)) != NULL) {
 			TAILQ_REMOVE(&list->allio, tio, links);
 			ctl_free_io(tio->io);
+			free(tio->buf, M_CTL);
 			free(tio, M_CTL);
 		}
-		free(list->buf, M_CTL);
 		if (list->abort) {
 			ctl_set_task_aborted(list->ctsio);
 			return (CTL_RETVAL_ERROR);
@@ -1233,8 +1233,6 @@ tpc_process_wut(struct tpc_list *list)
 		return (CTL_RETVAL_ERROR);
 	}
 
-	list->buf = malloc(numbytes, M_CTL, M_WAITOK |
-	    (list->token == NULL ? M_ZERO : 0));
 	list->segbytes = numbytes;
 	list->segsectors = numbytes / dstblock;
 //printf("Copy chunk of %ju sectors from %ju to %ju\n", list->segsectors,
@@ -1257,11 +1255,12 @@ tpc_process_wut(struct tpc_list *list)
 
 		tior = malloc(sizeof(*tior), M_CTL, M_WAITOK | M_ZERO);
 		TAILQ_INIT(&tior->run);
+		tior->buf = malloc(roundbytes, M_CTL, M_WAITOK);
 		tior->list = list;
 		TAILQ_INSERT_TAIL(&list->allio, tior, links);
 		tior->io = tpcl_alloc_io();
 		ctl_scsi_read_write(tior->io,
-				    /*data_ptr*/ &list->buf[donebytes],
+				    /*data_ptr*/ tior->buf,
 				    /*data_len*/ roundbytes,
 				    /*read_op*/ 1,
 				    /*byte2*/ 0,
@@ -1280,7 +1279,7 @@ tpc_process_wut(struct tpc_list *list)
 		TAILQ_INSERT_TAIL(&list->allio, tiow, links);
 		tiow->io = tpcl_alloc_io();
 		ctl_scsi_read_write(tiow->io,
-				    /*data_ptr*/ &list->buf[donebytes],
+				    /*data_ptr*/ tior->buf,
 				    /*data_len*/ roundbytes,
 				    /*read_op*/ 0,
 				    /*byte2*/ 0,