Commit 7fb0e1a6 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Greg Kroah-Hartman
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Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor function 



Commit 79208c57 ("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: default avatarLaszlo Ersek <lersek@redhat.com>
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d6cbd2c3

drivers/hv/hv_balloon.c

+4 −4
Original line number Diff line number Diff line
@@ -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;

}