From: Ilpo Järvinen Date: Fri, 4 Aug 2006 23:36:18 +0000 (-0700) Subject: [PKT_SCHED] RED: Fix overflow in calculation of queue average X-Git-Tag: v2.6.18-rc4~3^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c4c0ce5c57ef0ca47a4428a14de6b5c8cdf8de8a;p=pandora-kernel.git [PKT_SCHED] RED: Fix overflow in calculation of queue average Overflow can occur very easily with 32 bits, e.g., with 1 second us_idle is approx. 2^20, which leaves only 11-Wlog bits for queue length. Since the EWMA exponent is typically around 9, queue lengths larger than 2^2 cause overflow. Whether the affected branch is taken when us_idle is as high as 1 second, depends on Scell_log, but with rather reasonable configuration Scell_log is large enough to cause p->Stab to have zero index, which always results zero shift (typically also few other small indices result in zero shift). Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- Reading git-diff-tree failed