- 17 Apr, 2015 5 commits
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Rasmus Villemoes authored
The most expensive part of decimal conversion is the divisions by 10 (albeit done using reciprocal multiplication with appropriately chosen constants). I decided to see if one could eliminate around half of these multiplications by emitting two digits at a time, at the cost of a 200 byte lookup table, and it does indeed seem like there is something to be gained, especially on 64 bits. Microbenchmarking shows improvements ranging from -50% (for numbers uniformly distributed in [0, 2^64-1]) to -25% (for numbers heavily biased toward the smaller end, a more realistic distribution). On a larger scale, perf shows that top, one of the big consumers of /proc data, uses 0.5-1.0% fewer cpu cycles. I had to jump through some hoops to get the 32 bit code to compile and run on my 64 bit machine, so I'm not sure how relevant these numbers are, but just for comparison the microbenchmark showed improvements between -30% and -10%. The bloat-o-meter costs are around 150 bytes (the generated code is a little smaller, so it's not the full 200 bytes) on both 32 and 64 bit. I'm aware that extra cache misses won't show up in a microbenchmark as used above, but on the other hand decimal conversions often happen in bulk (for example in the case of top). I have of course tested that the new code generates the same output as the old, for both the first and last 1e10 numbers in [0,2^64-1] and 4e9 'random' numbers in-between. Test and verification code on github: https://github.com/Villemoes/dec. Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Tested-by:
Jeff Epler <jepler@unpythonic.net> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Joe Perches <joe@perches.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Yury Norov authored
This file contains implementation for all find_*_bit{,_le} So giving it more generic name looks reasonable. Signed-off-by:Yury Norov <yury.norov@gmail.com> Reviewed-by:
George Spelvin <linux@horizon.com> Cc: Alexey Klimov <klimov.linux@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Mark Salter <msalter@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Thomas Graf <tgraf@suug.ch> Cc: Valentin Rothberg <valentinrothberg@gmail.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by:
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Yury Norov authored
Currently all 'find_*_bit' family is located in lib/find_next_bit.c, except 'find_last_bit', which is in lib/find_last_bit.c. It seems, there's no major benefit to have it separated. Signed-off-by:
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Yury Norov authored
This patchset does rework to find_bit function family to achieve better performance, and decrease size of text. All rework is done in patch 1. Patches 2 and 3 are about code moving and renaming. It was boot-tested on x86_64 and MIPS (big-endian) machines. Performance tests were ran on userspace with code like this: /* addr[] is filled from /dev/urandom */ start = clock(); while (ret < nbits) ret = find_next_bit(addr, nbits, ret + 1); end = clock(); printf("%ld\t", (unsigned long) end - start); On Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz measurements are: (for find_next_bit, nbits is 8M, for find_first_bit - 80K) find_next_bit: find_first_bit: new current new current 26932 43151 14777 14925 26947 43182 14521 15423 26507 43824 15053 14705 27329 43759 14473 14777 26895 43367 14847 15023 26990 43693 15103 15163 26775 43299 15067 15232 27282 42752 14544 15121 27504 43088 14644 14858 26761 43856 14699 15193 26692 43075 14781 14681 27137 42969 14451 15061 ... ... find_next_bit performance gain is 35-40%; find_first_bit - no measurable difference. On ARM machine, there is arch-specific implementation for find_bit. Thanks a lot to George Spelvin and Rasmus Villemoes for hints and helpful discussions. This patch (of 3): New implementations takes less space in source file (see diffstat) and in object. For me it's 710 vs 453 bytes of text. It also shows better performance. find_last_bit description fixed due to obvious typo. [akpm@linux-foundation.org: include linux/bitmap.h, per Rasmus] Signed-off-by: -
Richard Weinberger authored
Removal of exec domains uncovered this new warning. processor.h re-used struct pt_regs from personality.h which is now gone. ./arch/alpha/include/asm/processor.h:47:33: warning: 'struct pt_regs' declared inside parameter list [enabled by default] Signed-off-by:
Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Signed-off-by:
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- 16 Apr, 2015 1 commit
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Herbert Xu authored
Commit 9c521a20 ("crypto: api - remove instance when test failed") tried to grab a module reference count before the module was even set. Worse, it then goes on to free the module reference count after it is set so you quickly end up with a negative module reference count which prevents people from using any instances belonging to that module. This patch moves the module initialisation before the reference count. Reported-by:
Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:
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- 15 Apr, 2015 34 commits
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Linus Torvalds authored
Merge second patchbomb from Andrew Morton: - the rest of MM - various misc bits - add ability to run /sbin/reboot at reboot time - printk/vsprintf changes - fiddle with seq_printf() return value * akpm: (114 commits) parisc: remove use of seq_printf return value lru_cache: remove use of seq_printf return value tracing: remove use of seq_printf return value cgroup: remove use of seq_printf return value proc: remove use of seq_printf return value s390: remove use of seq_printf return value cris fasttimer: remove use of seq_printf return value cris: remove use of seq_printf return value openrisc: remove use of seq_printf return value ARM: plat-pxa: remove use of seq_printf return value nios2: cpuinfo: remove use of seq_printf return value microblaze: mb: remove use of seq_printf return value ipc: remove use of seq_printf return value rtc: remove use of seq_printf return value power: wakeup: remove use of seq_printf return value x86: mtrr: if: remove use of seq_printf return value linux/bitmap.h: improve BITMAP_{LAST,FIRST}_WORD_MASK MAINTAINERS: CREDITS: remove Stefano Brivio from B43 .mailmap: add Ricardo Ribalda CREDITS: add Ricardo Ribalda Delgado ... -
Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
Joe Perches <joe@perches.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Miscellanea: o Remove unused return value from trace_lookup_stack Signed-off-by:
Steven Rostedt <rostedt@goodmis.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Miscellanea: o Coalesce formats, realign arguments Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, (as it is here, it doesn't return # of chars emitted) will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
Michal Simek <monstr@monstr.eu> Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Joe Perches authored
The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Signed-off-by:
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Rasmus Villemoes authored
The macro BITMAP_LAST_WORD_MASK can be implemented without a conditional, which will generally lead to slightly better generated code (221 bytes saved for allmodconfig-GCOV_KERNEL, ~2k with GCOV_KERNEL). As a small bonus, this also ensures that the nbits parameter is expanded exactly once. In BITMAP_FIRST_WORD_MASK, if start is signed gcc is technically allowed to assume it is positive (or divisible by BITS_PER_LONG), and hence just do the simple mask. It doesn't seem to use this, and even on an architecture like x86 where the shift only depends on the lower 5 or 6 bits, and these bits are not affected by the signedness of the expression, gcc still generates code to compute the C99 mandated value of start % BITS_PER_LONG. So just use a mask explicitly, also for consistency with BITMAP_LAST_WORD_MASK. Signed-off-by:
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Joe Perches authored
This email address isn't working anymore Signed-off-by:
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Ricardo Ribalda Delgado authored
Work and Home computer had different settings in the mail client. Some contributions appear as Ricardo Ribalda, others as Ricardo Ribalda Delgado (and one as just Ricardo). Signed-off-by:
Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by:
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Ricardo Ribalda Delgado authored
Add personal details to CREDITS file. Signed-off-by:
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Joe Perches authored
Consistently use a single tab after the "specifier:" type. Signed-off-by:
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Rasmus Villemoes authored
The current semantics of string_escape_mem are inadequate for one of its current users, vsnprintf(). If that is to honour its contract, it must know how much space would be needed for the entire escaped buffer, and string_escape_mem provides no way of obtaining that (short of allocating a large enough buffer (~4 times input string) to let it play with, and that's definitely a big no-no inside vsnprintf). So change the semantics for string_escape_mem to be more snprintf-like: Return the size of the output that would be generated if the destination buffer was big enough, but of course still only write to the part of dst it is allowed to, and (contrary to snprintf) don't do '\0'-termination. It is then up to the caller to detect whether output was truncated and to append a '\0' if desired. Also, we must output partial escape sequences, otherwise a call such as snprintf(buf, 3, "%1pE", "\123") would cause printf to write a \0 to buf[2] but leaving buf[0] and buf[1] with whatever they previously contained. This also fixes a bug in the escaped_string() helper function, which used to unconditionally pass a length of "end-buf" to string_escape_mem(); since the latter doesn't check osz for being insanely large, it would happily write to dst. For example, kasprintf(GFP_KERNEL, "something and then %pE", ...); is an easy way to trigger an oops. In test-string_helpers.c, the -ENOMEM test is replaced with testing for getting the expected return value even if the buffer is too small. We also ensure that nothing is written (by relying on a NULL pointer deref) if the output size is 0 by passing NULL - this has to work for kasprintf("%pE") to work. In net/sunrpc/cache.c, I think qword_add still has the same semantics. Someone should definitely double-check this. In fs/proc/array.c, I made the minimum possible change, but longer-term it should stop poking around in seq_file internals. [andriy.shevchenko@linux.intel.com: simplify qword_add] [andriy.shevchenko@linux.intel.com: add missed curly braces] Signed-off-by:Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by:
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Rasmus Villemoes authored
When printf is given the format specifier %pE, it needs a way of obtaining the total output size that would be generated if the buffer was large enough, and string_escape_mem doesn't easily provide that. This is a refactorization of string_escape_mem in preparation of changing its external API to provide that information. The somewhat ugly early returns and subsequent seemingly redundant conditionals are to make the following patch touch as little as possible in string_helpers.c while still preserving the current behaviour of never outputting partial escape sequences. That behaviour must also change for %pE to work as one expects from every other printf specifier. Signed-off-by:
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Rasmus Villemoes authored
The helper hex_string() is broken in two ways. First, it doesn't increment buf regardless of whether there is room to print, so callers such as kasprintf() that try to probe the correct storage to allocate will get a too small return value. But even worse, kasprintf() (and likely anyone else trying to find the size of the result) pass NULL for buf and 0 for size, so we also have end == NULL. But this means that the end-1 in hex_string() is (char*)-1, so buf < end-1 is true and we get a NULL pointer deref. I double-checked this with a trivial kernel module that just did a kasprintf(GFP_KERNEL, "%14ph", "CrashBoomBang"). Nobody seems to be using %ph with kasprintf, but we might as well fix it before it hits someone. Signed-off-by:
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Geert Uytterhoeven authored
Add format specifiers for printing struct clk: - '%pC' or '%pCn': name (Common Clock Framework) or address (legacy clock framework) of the clock, - '%pCr': rate of the clock. [akpm@linux-foundation.org: omit code if !CONFIG_HAVE_CLK] Signed-off-by:Geert Uytterhoeven <geert+renesas@glider.be> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Turquette <mturquette@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by:
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Geert Uytterhoeven authored
Move the format types for 64-bit integers and configurable size integers to the top, so they're next to the other integer format types. While at it, add the missing format types for s32 and u32. Signed-off-by:
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Geert Uytterhoeven authored
This patch series improves the documentation for printk() formats, and adds support for printing clocks. The latter has always been a hassle if you wanted to support both the common and legacy clock frameworks. - '%pC' and '%pCn' print the name (Common Clock Framework) or address (legacy clock framework) of a clock, - '%pCr' prints the current clock rate. This patch (of 3): Make sure all %p extensions that take parameters by references are documented to do so. Signed-off-by: -
Rasmus Villemoes authored
Making ZEROPAD == '0'-' ', we can eliminate a few more instructions. Signed-off-by:
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Rasmus Villemoes authored
gcc doesn't merge or overlap const char[] objects with identical contents (probably language lawyers would also insist that these things have different addresses), but there's no reason to have the string "0123456789ABCDEF" occur in multiple places. hex_asc_upper is declared in kernel.h and defined in lib/hexdump.c, which is unconditionally compiled in. Signed-off-by:
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Rasmus Villemoes authored
At least since the initial git commit, when base was passed as a separate parameter, number() has only been called with bases 8, 10 and 16. I'm guessing that 66 was to accommodate 64 0/1, a sign and a '\0', but the buffer is only used for the actual digits. Octal digits carry 3 bits of information, so 24 is enough. Spell that 3*sizeof(num) so one less place needs to be changed should long long ever be 128 bits. Also remove the commented-out code that would handle an arbitrary base. Signed-off-by:
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Rasmus Villemoes authored
Since FORMAT_TYPE_INT is simply 1 more than FORMAT_TYPE_UINT, and similarly for BYTE/UBYTE, SHORT/USHORT, LONG/ULONG, we can eliminate a few instructions by making SIGN have the value 1 instead of 2, and then use arithmetic instead of branches for computing the right spec->type. It's a little hacky, but certainly in the same spirit as SMALL needing to have the value 0x20. For example for the spec->qualifier == 'l' case, gcc now generates 75e: 0f b6 53 01 movzbl 0x1(%rbx),%edx 762: 83 e2 01 and $0x1,%edx 765: 83 c2 09 add $0x9,%edx 768: 88 13 mov %dl,(%rbx) instead of 763: 0f b6 53 01 movzbl 0x1(%rbx),%edx 767: 83 e2 02 and $0x2,%edx 76a: 80 fa 01 cmp $0x1,%dl 76d: 19 d2 sbb %edx,%edx 76f: 83 c2 0a add $0xa,%edx 772: 88 13 mov %dl,(%rbx) Signed-off-by: -
Steven Rostedt authored
KERN_CONT is nicely commented in kern_levels.h, but pr_cont() is now used more often, and it lacks the comment stating what it is used for. It can be confused as continuing the log level, but that is not its purpose. Its purpose is to continue a line that had no newline enclosed. This should be documented by pr_cont() as well. Signed-off-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
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Joel Stanley authored
Use orderly_reboot so userspace will to shut itself down via the reboot path. This is required for graceful reboot initiated by the BMC, such as when a user uses ipmitool to issue a 'chassis power cycle' command. Signed-off-by:
Joel Stanley <joel@jms.id.au> Acked-by:
Michael Ellerman <mpe@ellerman.id.au> Cc: Fabian Frederick <fabf@skynet.be> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: David S. Miller <davem@davemloft.net> Signed-off-by:
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