Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor function

Commit 79208c57da53 ("Drivers: hv: hv_balloon: Make adjustments in computing
the floor") was inacurate as it introduced a jump in our piecewiese linear
'floor' function:

At 2048MB we have:
Left limit:
104 + 2048/8 = 360
Right limit:
256 + 2048/16 = 384 (so the right value is 232)

We now have to make an adjustment at 8192 boundary:
232 + 8192/16 = 744
512 + 8192/32 = 768 (so the right value is 488)

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 99afef9393aafe6837a0a573076ffba6d93ab9f5..4f5323cedab3913f57ae5054c3ccfc915a6e16f0 100644 (file)
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -976,8 +976,8 @@ static unsigned long compute_balloon_floor(void)
         *     128        72    (1/2)
         *     512       168    (1/4)
         *    2048       360    (1/8)
-        *    8192       768    (1/16)
-        *   32768      1536    (1/32)
+        *    8192       744    (1/16)
+        *   32768      1512    (1/32)
         */
        if (totalram_pages < MB2PAGES(128))
                min_pages = MB2PAGES(8) + (totalram_pages >> 1);
@@ -986,9 +986,9 @@ static unsigned long compute_balloon_floor(void)
        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);
+               min_pages = MB2PAGES(232) + (totalram_pages >> 4);
        else
-               min_pages = MB2PAGES(512) + (totalram_pages >> 5);
+               min_pages = MB2PAGES(488) + (totalram_pages >> 5);
 #undef MB2PAGES
        return min_pages;
 }