Patchwork [8/9] user: speed up init_paths a bit

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Submitter Mike Frysinger
Date Feb. 7, 2011, 6:05 a.m.
Message ID <1297058757-7611-8-git-send-email-vapier@gentoo.org>
Download mbox | patch
Permalink /patch/82245/
State New
Headers show

Comments

Mike Frysinger - Feb. 7, 2011, 6:05 a.m.
The current init_paths code will attempt to opendir() every single file it
finds.  This can obviously generated a huge number of syscalls with even a
moderately small sysroot that will fail.  Since the readdir() call provides
the file type in the struct itself, use it.  On my system, this prevents
over 1000 syscalls from being made at every invocation of a target binary,
and I only have a C library installed.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
 path.c |   28 ++++++++++++++++++++++------
 1 files changed, 22 insertions(+), 6 deletions(-)

Patch

diff --git a/path.c b/path.c
index 0d2bf14..ef3f277 100644
--- a/path.c
+++ b/path.c
@@ -38,7 +38,8 @@  static int strneq(const char *s1, unsigned int n, const char *s2)
     return s2[i] == 0;
 }
 
-static struct pathelem *add_entry(struct pathelem *root, const char *name);
+static struct pathelem *add_entry(struct pathelem *root, const char *name,
+                                  unsigned char type);
 
 static struct pathelem *new_entry(const char *root,
                                   struct pathelem *parent,
@@ -56,6 +57,15 @@  static struct pathelem *new_entry(const char *root,
 
 #define streq(a,b) (strcmp((a), (b)) == 0)
 
+/* Not all systems provide this feature */
+#if defined(DT_DIR) && defined(DT_UNKNOWN)
+# define dirent_type(dirent) ((dirent)->d_type)
+# define is_dir_maybe(type)  ((type) == DT_DIR || (type) == DT_UNKNOWN)
+#else
+# define dirent_type(dirent) (1)
+# define is_dir_maybe(type)  (type)
+#endif
+
 static struct pathelem *add_dir_maybe(struct pathelem *path)
 {
     DIR *dir;
@@ -65,7 +75,7 @@  static struct pathelem *add_dir_maybe(struct pathelem *path)
 
         while ((dirent = readdir(dir)) != NULL) {
             if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
-                path = add_entry(path, dirent->d_name);
+                path = add_entry(path, dirent->d_name, dirent_type(dirent));
             }
         }
         closedir(dir);
@@ -73,16 +83,22 @@  static struct pathelem *add_dir_maybe(struct pathelem *path)
     return path;
 }
 
-static struct pathelem *add_entry(struct pathelem *root, const char *name)
+static struct pathelem *add_entry(struct pathelem *root, const char *name,
+                                  unsigned char type)
 {
+    struct pathelem **e;
+
     root->num_entries++;
 
     root = realloc(root, sizeof(*root)
                    + sizeof(root->entries[0])*root->num_entries);
+    e = &root->entries[root->num_entries-1];
+
+    *e = new_entry(root->pathname, root, name);
+    if (is_dir_maybe(type)) {
+        *e = add_dir_maybe(*e);
+    }
 
-    root->entries[root->num_entries-1] = new_entry(root->pathname, root, name);
-    root->entries[root->num_entries-1]
-        = add_dir_maybe(root->entries[root->num_entries-1]);
     return root;
 }