From 5756b76e4db643d8f75174a9a50038523d4b9e32 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 5 Mar 2012 16:49:24 +0000 Subject: vsprintf: make %pV handling compatible with kasprintf() kasprintf() (and potentially other functions that I didn't run across so far) want to evaluate argument lists twice. Caring to do so for the primary list is obviously their job, but they can't reasonably be expected to check the format string for instances of %pV, which however need special handling too: On architectures like x86-64 (as opposed to e.g. ix86), using the same argument list twice doesn't produce the expected results, as an internally managed cursor gets updated during the first run. Fix the problem by always acting on a copy of the original list when handling %pV. Signed-off-by: Jan Beulich Signed-off-by: Linus Torvalds --- lib/vsprintf.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 8e75003d62f6..38e612e66da5 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -891,9 +891,15 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'U': return uuid_string(buf, end, ptr, spec, fmt); case 'V': - return buf + vsnprintf(buf, end > buf ? end - buf : 0, - ((struct va_format *)ptr)->fmt, - *(((struct va_format *)ptr)->va)); + { + va_list va; + + va_copy(va, *((struct va_format *)ptr)->va); + buf += vsnprintf(buf, end > buf ? end - buf : 0, + ((struct va_format *)ptr)->fmt, va); + va_end(va); + return buf; + } case 'K': /* * %pK cannot be used in IRQ context because its test -- cgit v1.2.3 From 8bc3bcc93a2b4e47d5d410146f6546bca6171663 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Wed, 16 Nov 2011 21:29:17 -0500 Subject: lib: reduce the use of module.h wherever possible 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 --- lib/vsprintf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 8e75003d62f6..7f29bfce8402 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -17,7 +17,7 @@ */ #include -#include +#include /* for KSYM_SYMBOL_LEN */ #include #include #include -- cgit v1.2.3 From 1ac101a5d675aca2426c5cd460c73fb95acb8391 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 23 Mar 2012 15:02:54 -0700 Subject: procfs: add num_to_str() to speed up /proc/stat == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrea Righi Cc: Eric Dumazet Cc: Glauber Costa Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Paul Turner Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/vsprintf.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 38e612e66da5..385c40291cdb 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -212,6 +212,26 @@ char *put_dec(char *buf, unsigned long long num) } } +/* + * Convert passed number to decimal string. + * Returns the length of string. On buffer overflow, returns 0. + * + * If speed is not important, use snprintf(). It's easy to read the code. + */ +int num_to_str(char *buf, int size, unsigned long long num) +{ + char tmp[21]; /* Enough for 2^64 in decimal */ + int idx, len; + + len = put_dec(tmp, num) - tmp; + + if (len > size) + return 0; + for (idx = 0; idx < len; ++idx) + buf[idx] = tmp[len - idx - 1]; + return len; +} + #define ZEROPAD 1 /* pad with zero */ #define SIGN 2 /* unsigned/signed long */ #define PLUS 4 /* show plus */ -- cgit v1.2.3