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Date: Fri, 27 Nov 2015 14:21:29 +0800 From: "Wangnan (F)" <wangnan0@...wei.com> To: Arnaldo Carvalho de Melo <acme@...nel.org> CC: <masami.hiramatsu.pt@...achi.com>, <ast@...nel.org>, <lizefan@...wei.com>, <pi3orama@....com>, <linux-kernel@...r.kernel.org>, Namhyung Kim <namhyung@...nel.org> Subject: Re: [PATCH 04/16] bpf tools: Collect map definition in bpf_object On 2015/11/27 14:16, Wangnan (F) wrote: > > > On 2015/11/27 4:56, Arnaldo Carvalho de Melo wrote: >> Em Tue, Nov 24, 2015 at 01:36:09PM +0000, Wang Nan escreveu: > > [SNIP] [SNIP] >>> + >>> + if ((prev < s) || (prev >= e)) { >>> + pr_warning("error: map handler doesn't belong to object\n"); >> I wonder if this shouldn't be made pr_debug, and as well have a function >> prefix, otherwise we may think this is related to some other kind of >> map, so I suggest: >> pr_debug("%s: error: map handler doesn't belong to object\n", >> __func__); >> >> Or at least: >> >> pr_debug("BPF error: map handler doesn't belong to object\n"); > > We always have a libbpf prefix before debug info from libbpf. Please see > > static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr; > static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr; > static __printf(1, 2) libbpf_print_fn_t __pr_debug; > #define __pr(func, fmt, ...) \ > do { \ > if ((func)) \ > (func)("libbpf: " fmt, ##__VA_ARGS__); \ > } while (0) > > #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__) > #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__) > #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__) > > We allow __pr_{warning,info,debug} be overwritten but the 'libbpf:' > prefix is > always there. > > Also, don't forget in perf's context libbpf is muted. > Sorry, Shoule be "muted in most case"... Here's an example: $ sudo ./perf record -v -e ./test_bpf_base.c ls ... ude/uapi -Iinclude/generated/uapi -include /home/w00229757/linux-hydrogen/include/linux/kconfig.h set env: WORKING_DIR=/lib/modules/4.3.0-rc4+/build set env: CLANG_SOURCE=/home/w00229757/./test_bpf_base.c llvm compiling command template: $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o - libbpf: loading object './test_bpf_base.c' from buffer libbpf: section .strtab, size 112, link 0, flags 0, type=3 libbpf: section .text, size 0, link 0, flags 6, type=1 libbpf: section .data, size 0, link 0, flags 3, type=1 ... libbpf: kernel version of ./test_bpf_base.c is 40300 libbpf: section .symtab, size 96, link 1, flags 0, type=2 bpf: config program 'func_write=vfs_write file->f_mode' symbol:vfs_write file:(null) line:0 offset:0 return:0 lazy:(null) parsing arg: file->f_mode into file, f_mode(1) bpf: config 'func_write=vfs_write file->f_mode' is ok If the error you pointed out is triggered, it should be: libbpf: error: map handler doesn't belong to object ... So we can always find which error message is belone to libbpf and which is belone to perf. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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