+ vgacon-optimize-scrolling.patch added to -mm tree

+ vgacon-optimize-scrolling.patch added to -mm tree

[akpm]

The patch titled
     vgacon: optimize scrolling
has been added to the -mm tree.  Its filename is
     vgacon-optimize-scrolling.patch

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*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://userweb.kernel.org/~akpm/added-to-mm.txt to find
out what to do about this

The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/

------------------------------------------------------
Subject: vgacon: optimize scrolling
From: Marcin Slusarz <marcin.slusarz@gmail.com>

Join multiple scr_memcpyw into 1-3 calls (usually 2).  (benchmarked
average speedup: 1%)

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/video/console/vgacon.c |   27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff -puN drivers/video/console/vgacon.c~vgacon-optimize-scrolling drivers/video/console/vgacon.c
--- a/drivers/video/console/vgacon.c~vgacon-optimize-scrolling
+++ a/drivers/video/console/vgacon.c
@@ -292,23 +292,26 @@ static int vgacon_scrolldelta(struct vc_
 	d = (void *) c->vc_origin;
 	s = (void *) c->vc_screenbuf;
 
-	while (count--) {
-		scr_memcpyw(d, vgacon_scrollback + soff, c->vc_size_row);
-		d += c->vc_size_row;
-		soff += c->vc_size_row;
-
-		if (soff >= vgacon_scrollback_size)
-			soff = 0;
+	if (count) {
+		int copysize;
+		count *= c->vc_size_row;
+		/* how much memory to end of buffer left? */
+		copysize = min(count, vgacon_scrollback_size - soff);
+		scr_memcpyw(d, vgacon_scrollback + soff, copysize);
+		d += copysize;
+		count -= copysize;
+
+		if (count) {
+			scr_memcpyw(d, vgacon_scrollback, count);
+			d += count;
+		}
 	}
 
 	if (diff == c->vc_rows) {
 		vgacon_cursor(c, CM_MOVE);
 	} else {
-		while (diff--) {
-			scr_memcpyw(d, s, c->vc_size_row);
-			d += c->vc_size_row;
-			s += c->vc_size_row;
-		}
+		if (diff)
+			scr_memcpyw(d, s, diff * c->vc_size_row);
 	}
 
 	return 1;
_

Patches currently in -mm which might be from marcin.slusarz@gmail.com are

rtc-fix-kernel-panic-on-second-use-of-sigio-nofitication.patch
git-x86.patch
vgacon-optimize-scrolling.patch
vgacon-vgacon_scrolldelta-simplification.patch