svn commit: r367780 - stable/12/sys/cam/ctl

[Alexander Motin]

Author: mav
Date: Wed Nov 18 02:05:59 2020
New Revision: 367780
URL: https://svnweb.freebsd.org/changeset/base/367780

Log:
  MFC r367600: Make CTL nicer to increased MAXPHYS.
  
  Before this CTL always allocated MAXPHYS-sized buffers, even for 4KB I/O,
  that is even more overkill for MAXPHYS of 1MB.  This change limits maximum
  allocation to 512KB if MAXPHYS is bigger, plus if one is above 128KB, adds
  new 128KB UMA zone for smaller I/Os.  The patch factors out alloc/free,
  so later we could make it use more zones or malloc() if we'd like.

Modified:
  stable/12/sys/cam/ctl/ctl_backend_block.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/cam/ctl/ctl_backend_block.c
==============================================================================
--- stable/12/sys/cam/ctl/ctl_backend_block.c	Wed Nov 18 01:18:45 2020	(r367779)
+++ stable/12/sys/cam/ctl/ctl_backend_block.c	Wed Nov 18 02:05:59 2020	(r367780)
@@ -102,7 +102,7 @@ __FBSDID("$FreeBSD$");
  */
 #define	CTLBLK_HALF_IO_SIZE	(512 * 1024)
 #define	CTLBLK_MAX_IO_SIZE	(CTLBLK_HALF_IO_SIZE * 2)
-#define	CTLBLK_MAX_SEG		MAXPHYS
+#define	CTLBLK_MAX_SEG		MIN(CTLBLK_HALF_IO_SIZE, MAXPHYS)
 #define	CTLBLK_HALF_SEGS	MAX(CTLBLK_HALF_IO_SIZE / CTLBLK_MAX_SEG, 1)
 #define	CTLBLK_MAX_SEGS		(CTLBLK_HALF_SEGS * 2)
 
@@ -190,6 +190,9 @@ struct ctl_be_block_softc {
 	SLIST_HEAD(, ctl_be_block_lun)	 lun_list;
 	uma_zone_t			 beio_zone;
 	uma_zone_t			 buf_zone;
+#if (CTLBLK_MAX_SEG > 131072)
+	uma_zone_t			 buf128_zone;
+#endif
 };
 
 static struct ctl_be_block_softc backend_block_softc;
@@ -298,6 +301,32 @@ static struct ctl_backend_driver ctl_be_block_driver =
 MALLOC_DEFINE(M_CTLBLK, "ctlblock", "Memory used for CTL block backend");
 CTL_BACKEND_DECLARE(cbb, ctl_be_block_driver);
 
+static void
+ctl_alloc_seg(struct ctl_be_block_softc *softc, struct ctl_sg_entry *sg,
+    size_t len)
+{
+
+#if (CTLBLK_MAX_SEG > 131072)
+	if (len <= 131072)
+		sg->addr = uma_zalloc(softc->buf128_zone, M_WAITOK);
+	else
+#endif
+		sg->addr = uma_zalloc(softc->buf_zone, M_WAITOK);
+	sg->len = len;
+}
+
+static void
+ctl_free_seg(struct ctl_be_block_softc *softc, struct ctl_sg_entry *sg)
+{
+
+#if (CTLBLK_MAX_SEG > 131072)
+	if (sg->len <= 131072)
+		uma_zfree(softc->buf128_zone, sg->addr);
+	else
+#endif
+		uma_zfree(softc->buf_zone, sg->addr);
+}
+
 static struct ctl_be_block_io *
 ctl_alloc_beio(struct ctl_be_block_softc *softc)
 {
@@ -315,12 +344,12 @@ ctl_free_beio(struct ctl_be_block_io *beio)
 	int i;
 
 	for (i = 0; i < beio->num_segs; i++) {
-		uma_zfree(softc->buf_zone, beio->sg_segs[i].addr);
+		ctl_free_seg(softc, &beio->sg_segs[i]);
 
 		/* For compare we had two equal S/G lists. */
 		if (beio->two_sglists) {
-			uma_zfree(softc->buf_zone,
-			    beio->sg_segs[i + CTLBLK_HALF_SEGS].addr);
+			ctl_free_seg(softc,
+			    &beio->sg_segs[i + CTLBLK_HALF_SEGS]);
 		}
 	}
 
@@ -1132,8 +1161,7 @@ ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_
 
 	/*
 	 * We have to limit our I/O size to the maximum supported by the
-	 * backend device.  Hopefully it is MAXPHYS.  If the driver doesn't
-	 * set it properly, use DFLTPHYS.
+	 * backend device.
 	 */
 	if (csw) {
 		max_iosize = dev->si_iosize_max;
@@ -1325,8 +1353,7 @@ ctl_be_block_cw_dispatch_ws(struct ctl_be_block_lun *b
 				seglen -= seglen % cbe_lun->blocksize;
 		} else
 			seglen -= seglen % cbe_lun->blocksize;
-		beio->sg_segs[i].len = seglen;
-		beio->sg_segs[i].addr = uma_zalloc(softc->buf_zone, M_WAITOK);
+		ctl_alloc_seg(softc, &beio->sg_segs[i], seglen);
 
 		DPRINTF("segment %d addr %p len %zd\n", i,
 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
@@ -1598,18 +1625,17 @@ ctl_be_block_dispatch(struct ctl_be_block_lun *be_lun,
 		/*
 		 * Setup the S/G entry for this chunk.
 		 */
-		beio->sg_segs[i].len = min(CTLBLK_MAX_SEG, len_left);
-		beio->sg_segs[i].addr = uma_zalloc(softc->buf_zone, M_WAITOK);
+		ctl_alloc_seg(softc, &beio->sg_segs[i],
+		    min(CTLBLK_MAX_SEG, len_left));
 
 		DPRINTF("segment %d addr %p len %zd\n", i,
 			beio->sg_segs[i].addr, beio->sg_segs[i].len);
 
 		/* Set up second segment for compare operation. */
 		if (beio->two_sglists) {
-			beio->sg_segs[i + CTLBLK_HALF_SEGS].len =
-			    beio->sg_segs[i].len;
-			beio->sg_segs[i + CTLBLK_HALF_SEGS].addr =
-			    uma_zalloc(softc->buf_zone, M_WAITOK);
+			ctl_alloc_seg(softc,
+			    &beio->sg_segs[i + CTLBLK_HALF_SEGS],
+			    beio->sg_segs[i].len);
 		}
 
 		beio->num_segs++;
@@ -1925,8 +1951,8 @@ ctl_be_block_open_dev(struct ctl_be_block_lun *be_lun,
 		maxio = dev->si_iosize_max;
 		if (maxio <= 0)
 			maxio = DFLTPHYS;
-		if (maxio > CTLBLK_MAX_IO_SIZE)
-			maxio = CTLBLK_MAX_IO_SIZE;
+		if (maxio > CTLBLK_MAX_SEG)
+			maxio = CTLBLK_MAX_SEG;
 	}
 	be_lun->lun_flush = ctl_be_block_flush_dev;
 	be_lun->getattr = ctl_be_block_getattr_dev;
@@ -2771,6 +2797,10 @@ ctl_be_block_init(void)
 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 	softc->buf_zone = uma_zcreate("ctlblock", CTLBLK_MAX_SEG,
 	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
+#if (CTLBLK_MAX_SEG > 131072)
+	softc->buf128_zone = uma_zcreate("ctlblock128", 131072,
+	    NULL, NULL, NULL, NULL, /*align*/ 0, /*flags*/0);
+#endif
 	SLIST_INIT(&softc->lun_list);
 	return (0);
 }
@@ -2797,6 +2827,9 @@ ctl_be_block_shutdown(void)
 	}
 	mtx_unlock(&softc->lock);
 	uma_zdestroy(softc->buf_zone);
+#if (CTLBLK_MAX_SEG > 131072)
+	uma_zdestroy(softc->buf128_zone);
+#endif
 	uma_zdestroy(softc->beio_zone);
 	mtx_destroy(&softc->lock);
 	sx_destroy(&softc->modify_lock);