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author | Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> | 2006-08-04 19:36:18 -0400 |
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committer | David S. Miller <davem@sunset.davemloft.net> | 2006-08-05 01:59:51 -0400 |
commit | c4c0ce5c57ef0ca47a4428a14de6b5c8cdf8de8a (patch) | |
tree | 762530925f75495b9d2b8bb35702060e7e2fa9ae /include/asm-m32r/mmu.h | |
parent | 30a584d944fbd599d4a8f470f75bf7af1a15b466 (diff) |
[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 <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/asm-m32r/mmu.h')
0 files changed, 0 insertions, 0 deletions