Messages in this thread Patch in this message | | | From | Chenggang Qin <> | Subject | [PATCH 1/2] perf core: avoid traverse dsos list while find vdso | Date | Thu, 5 Sep 2013 10:59:34 +0800 |
| |
From: Chenggang Qin <chenggang.qcg@taobao.com>
Vdso is only one in a system. It is not necessory to traverse the macine->user_dsos list while finding the dso of vdso. The flag vdso_found should be replaced by a pointor that point to the dso of vdso. If the pointer is NULL, dso of vdso have not been created. Else, the pointor can be returned directly in function vdso__dso_findnew(). The list traversing can be avoided by this method. Thanks.
Cc: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Yanmin Zhang <yanmin.zhang@intel.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Chenggang Qin <chenggang.qcg@taobao.com>
--- tools/perf/util/vdso.c | 22 ++++++++-------------- 1 files changed, 8 insertions(+), 14 deletions(-)
diff --git a/tools/perf/util/vdso.c b/tools/perf/util/vdso.c index 3915982..8022ef0 100644 --- a/tools/perf/util/vdso.c +++ b/tools/perf/util/vdso.c @@ -13,7 +13,7 @@ #include "symbol.h" #include "linux/string.h" -static bool vdso_found; +static struct dso *vdso_dso = NULL; static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX"; static int find_vdso_map(void **start, void **end) @@ -55,9 +55,6 @@ static char *get_file(void) size_t size; int fd; - if (vdso_found) - return vdso_file; - if (find_vdso_map(&start, &end)) return NULL; @@ -79,33 +76,30 @@ static char *get_file(void) out: free(buf); - vdso_found = (vdso != NULL); return vdso; } void vdso__exit(void) { - if (vdso_found) + if (vdso_dso) unlink(vdso_file); } struct dso *vdso__dso_findnew(struct list_head *head) { - struct dso *dso = dsos__find(head, VDSO__MAP_NAME, true); - - if (!dso) { + if (!vdso_dso) { char *file; file = get_file(); if (!file) return NULL; - dso = dso__new(VDSO__MAP_NAME); - if (dso != NULL) { - dsos__add(head, dso); - dso__set_long_name(dso, file); + vdso_dso = dso__new(VDSO__MAP_NAME); + if (vdso_dso != NULL) { + dsos__add(head, vdso_dso); + dso__set_long_name(vdso_dso, file); } } - return dso; + return vdso_dso; } -- 1.7.8.rc2.5.g815b
| |