Both VMX and SVM propagate virtual_tsc_khz in the same way, so this
patch removes the call-back set_tsc_khz() and replaces it with a common
function.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
VMX and SVM calculate the TSC scaling ratio in a similar logic, so this
patch generalizes it to a common TSC scaling function.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
[Inline the multiplication and shift steps into mul_u64_u64_shr. Remove
BUG_ON. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit f792685006 ("math64: New
div64_u64_rem helper") implemented div64_u64 in terms of div64_u64_rem.
But div64_u64_rem was removed because it slowed down div64_u64 (and
there were no other users of div64_u64_rem).
Device Mapper's I/O statistics support has a need for div64_u64_rem;
reintroduce this helper as a separate method that doesn't slow down
div64_u64, especially on 32-bit systems.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
There is div64_long() to handle the s64/long division, but no mocro do
u64/ul division. It is necessary in some scenarios, so add this
function.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alex Shi <alex.shi@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
iter_div_u64_rem is used in the x86-64 vdso, which cannot call other
kernel code. For this case, provide the always_inlined version,
__iter_div_u64_rem.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have a few instances of the open-coded iterative div/mod loop, used
when we don't expcet the dividend to be much bigger than the divisor.
Unfortunately modern gcc's have the tendency to strength "reduce" this
into a full mod operation, which isn't necessarily any faster, and
even if it were, doesn't exist if gcc implements it in libgcc.
The workaround is to put a dummy asm statement in the loop to prevent
gcc from performing the transformation.
This patch creates a single implementation of this loop, and uses it
to replace the open-coded versions I know about.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The current do_div doesn't explicitly say that it's unsigned and the signed
counterpart is missing, which is e.g. needed when dealing with time values.
This introduces 64bit signed/unsigned divide functions which also attempts to
cleanup the somewhat awkward calling API, which often requires the use of
temporary variables for the dividend. To avoid the need for temporary
variables everywhere for the remainder, each divide variant also provides a
version which doesn't return the remainder.
Each architecture can now provide optimized versions of these function,
otherwise generic fallback implementations will be used.
As an example I provided an alternative for the current x86 divide, which
avoids the asm casts and using an union allows gcc to generate better code.
It also avoids the upper divde in a few more cases, where the result is known
(i.e. upper quotient is zero).
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
