Commit 7fb0e1a6 authored Mar 27, 2015 by Vitaly Kuznetsov Committed by Greg Kroah-Hartman Apr 03, 2015

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: 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>

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;
		}

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