svn commit: r278510 - in stable/10/sys: conf dev/usb

[Hans Petter Selasky]

Author: hselasky
Date: Tue Feb 10 13:25:29 2015
New Revision: 278510
URL: https://svnweb.freebsd.org/changeset/base/278510

Log:
  MFC r278074:
  Optimise allocation of USB DMA structures. By default don't double map
  allocations if only one element should be allocated per page
  cache. Make one allocation per element compile time configurable. Fix
  a comment while at it.

Modified:
  stable/10/sys/conf/options
  stable/10/sys/dev/usb/usb_transfer.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/conf/options
==============================================================================
--- stable/10/sys/conf/options	Tue Feb 10 13:20:34 2015	(r278509)
+++ stable/10/sys/conf/options	Tue Feb 10 13:25:29 2015	(r278510)
@@ -663,6 +663,7 @@ USB_HOST_ALIGN		opt_usb.h
 USB_REQ_DEBUG		opt_usb.h
 USB_TEMPLATE		opt_usb.h
 USB_VERBOSE		opt_usb.h
+USB_DMA_SINGLE_ALLOC	opt_usb.h
 USB_EHCI_BIG_ENDIAN_DESC	opt_usb.h
 U3G_DEBUG		opt_u3g.h
 UKBD_DFLT_KEYMAP	opt_ukbd.h

Modified: stable/10/sys/dev/usb/usb_transfer.c
==============================================================================
--- stable/10/sys/dev/usb/usb_transfer.c	Tue Feb 10 13:20:34 2015	(r278509)
+++ stable/10/sys/dev/usb/usb_transfer.c	Tue Feb 10 13:25:29 2015	(r278510)
@@ -237,7 +237,11 @@ usbd_transfer_setup_sub_malloc(struct us
 		n_obj = 1;
 	} else {
 		/* compute number of objects per page */
+#ifdef USB_DMA_SINGLE_ALLOC
+		n_obj = 1;
+#else
 		n_obj = (USB_PAGE_SIZE / size);
+#endif
 		/*
 		 * Compute number of DMA chunks, rounded up
 		 * to nearest one:
@@ -273,15 +277,33 @@ usbd_transfer_setup_sub_malloc(struct us
 		    &parm->curr_xfer->xroot->dma_parent_tag;
 	}
 
-	if (ppc) {
-		*ppc = parm->xfer_page_cache_ptr;
+	if (ppc != NULL) {
+		if (n_obj != 1)
+			*ppc = parm->xfer_page_cache_ptr;
+		else
+			*ppc = parm->dma_page_cache_ptr;
 	}
 	r = count;			/* set remainder count */
 	z = n_obj * size;		/* set allocation size */
 	pc = parm->xfer_page_cache_ptr;
 	pg = parm->dma_page_ptr;
 
-	for (x = 0; x != n_dma_pc; x++) {
+	if (n_obj == 1) {
+	    /*
+	     * Avoid mapping memory twice if only a single object
+	     * should be allocated per page cache:
+	     */
+	    for (x = 0; x != n_dma_pc; x++) {
+		if (usb_pc_alloc_mem(parm->dma_page_cache_ptr,
+		    pg, z, align)) {
+			return (1);	/* failure */
+		}
+		/* Make room for one DMA page cache and "n_dma_pg" pages */
+		parm->dma_page_cache_ptr++;
+		pg += n_dma_pg;
+	    }
+	} else {
+	    for (x = 0; x != n_dma_pc; x++) {
 
 		if (r < n_obj) {
 			/* compute last remainder */
@@ -294,7 +316,7 @@ usbd_transfer_setup_sub_malloc(struct us
 		}
 		/* Set beginning of current buffer */
 		buf = parm->dma_page_cache_ptr->buffer;
-		/* Make room for one DMA page cache and one page */
+		/* Make room for one DMA page cache and "n_dma_pg" pages */
 		parm->dma_page_cache_ptr++;
 		pg += n_dma_pg;
 
@@ -314,6 +336,7 @@ usbd_transfer_setup_sub_malloc(struct us
 			}
 			mtx_unlock(pc->tag_parent->mtx);
 		}
+	    }
 	}
 
 	parm->xfer_page_cache_ptr = pc;