Drivers: hv: hv_balloon: Make adjustments in computing the floor

Make adjustments in computing the balloon floor. The current computation
of the balloon floor was not appropriate for virtual machines with more than
10 GB of assigned memory - we would get into situations where the host would
agressively balloon down the guest and leave the guest in an unusable state.
This patch fixes the issue by raising the floor.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/hv_balloon.c

@@ -928,9 +928,8 @@ static unsigned long compute_balloon_floor(void)
 	 *     128        72    (1/2)
 	 *     512       168    (1/4)
 	 *    2048       360    (1/8)
-	 *    8192       552    (1/32)
-	 *   32768      1320
-	 *  131072      4392
+	 *    8192       768    (1/16)
+	 *   32768      1536	(1/32)
 	 */
 	if (totalram_pages < MB2PAGES(128))
 		min_pages = MB2PAGES(8) + (totalram_pages >> 1);
@@ -938,8 +937,10 @@ static unsigned long compute_balloon_floor(void)
 		min_pages = MB2PAGES(40) + (totalram_pages >> 2);
 	else if (totalram_pages < MB2PAGES(2048))
 		min_pages = MB2PAGES(104) + (totalram_pages >> 3);
+	else if (totalram_pages < MB2PAGES(8192))
+		min_pages = MB2PAGES(256) + (totalram_pages >> 4);
 	else
-		min_pages = MB2PAGES(296) + (totalram_pages >> 5);
+		min_pages = MB2PAGES(512) + (totalram_pages >> 5);
 #undef MB2PAGES
 	return min_pages;
 }