[PATCH 5/7] Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor function
From: K. Y. Srinivasan
Date: Fri Mar 27 2015 - 10:53:36 EST
From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/hv_balloon.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 99afef9..4f5323c 100644
--- 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;
}
--
1.7.4.1
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