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* lib: correct link to the original source for div64_u64Heinrich Schuchardt2015-03-061-1/+1
| | | | | | | | | | | The code refers to an invalid url http://www.hackersdelight.org/HDcode/newCode/divDouble.c.txt The correct url is http://www.hackersdelight.org/hdcodetxt/divDouble.c.txt Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* math64: New separate div64_u64_rem helperMike Snitzer2013-08-231-0/+40
| | | | | | | | | | | | | | | | | | Commit f792685006274a850e6cc0ea9ade275ccdfc90bc ("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>
* Revert "math64: New div64_u64_rem helper"Stanislaw Gruszka2013-04-301-13/+6
| | | | | | | | | | | | | | | | | This reverts commit f792685006274a850e6cc0ea9ade275ccdfc90bc. The cputime scaling code was changed/fixed and does not need the div64_u64_rem() primitive anymore. It has no other users, so let's remove them. Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: rostedt@goodmis.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dave Hansen <dave@sr71.net> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1367314507-9728-4-git-send-email-sgruszka@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* math64: New div64_u64_rem helperFrederic Weisbecker2013-03-131-6/+13
| | | | | | | | | | | | | | | Provide an extended version of div64_u64() that also returns the remainder of the division. We are going to need this to refine the cputime scaling code. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org>
* lib: correct link to the original source for div64_u64Akinobu Mita2012-06-281-1/+1
| | | | | | Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Jiri Kosina <trivial@kernel.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* lib: reduce the use of module.h wherever possiblePaul Gortmaker2012-03-071-1/+2
| | | | | | | | | | For files only using THIS_MODULE and/or EXPORT_SYMBOL, map them onto including export.h -- or if the file isn't even using those, then just delete the include. Fix up any implicit include dependencies that were being masked by module.h along the way. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* div64_u64(): improve precision on 32bit platformsBrian Behlendorf2010-10-261-10/+42
| | | | | | | | | | | | | | | | | | | | The current implementation of div64_u64 for 32bit systems returns an approximately correct result when the divisor exceeds 32bits. Since doing 64bit division using 32bit hardware is a long since solved problem we just use one of the existing proven methods. Additionally, add a div64_s64 function to correctly handle doing signed 64bit division. Addresses https://bugzilla.redhat.com/show_bug.cgi?id=616105 Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Ben Woodard <bwoodard@llnl.gov> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Mark Grondona <mgrondona@llnl.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add an inlined version of iter_div_u64_remJeremy Fitzhardinge2008-06-121-14/+1
| | | | | | | | | 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>
* common implementation of iterative div/modJeremy Fitzhardinge2008-06-121-0/+23
| | | | | | | | | | | | | | | | | | | | | | 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>
* rename div64_64 to div64_u64Roman Zippel2008-05-011-6/+6
| | | | | | | | | | | | | | | | | | | | | Rename div64_64 to div64_u64 to make it consistent with the other divide functions, so it clearly includes the type of the divide. Move its definition to math64.h as currently no architecture overrides the generic implementation. They can still override it of course, but the duplicated declarations are avoided. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: Avi Kivity <avi@qumranet.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* introduce explicit signed/unsigned 64bit divideRoman Zippel2008-05-011-2/+21
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [S390]: Fix build on 31-bit.David S. Miller2007-04-251-1/+1
| | | | | | | | | | | | Allow s390 to properly override the generic __div64_32() implementation by: 1) Using obj-y for div64.o in s390's makefile instead of lib-y 2) Adding the weak attribute to the generic implementation. Signed-off-by: David S. Miller <davem@davemloft.net>
* [LIB]: div64_64 optimizationStephen Hemminger2007-04-251-9/+7
| | | | | | | | Minor optimization of div64_64. do_div() already does optimization for the case of 32 by 32 divide, so no need to do it here. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: div64_64 consolidate (rev3)Stephen Hemminger2007-04-251-0/+22
| | | | | | | Here is the current version of the 64 bit divide common code. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+61
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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