sysctl: Make the header lists per directory.

Slightly enhance efficiency and clarity of the code by making the
header list per directory instead of per set.

Benchmark before:
    make-dummies 0 999 -> 0.63s
    rmmod dummy        -> 0.12s
    make-dummies 0 9999 -> 2m35s
    rmmod dummy         -> 18s

Benchmark after:
    make-dummies 0 999 -> 0.32s
    rmmod dummy        -> 0.12s
    make-dummies 0 9999 -> 1m17s
    rmmod dummy         -> 17s

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 160d5781638ec6d127d54780dbd8b62324d1280f..e971ccccac4a5ce9ca21177d2e4dde7499dd4f48 100644 (file)
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -33,12 +33,12 @@ static struct ctl_table root_table[] = {
        { }
 };
 static struct ctl_table_root sysctl_table_root = {
-       .default_set.list = LIST_HEAD_INIT(sysctl_table_root.default_set.dir.header.ctl_entry),
+       .default_set.dir.list = LIST_HEAD_INIT(sysctl_table_root.default_set.dir.list),
        .default_set.dir.header = {
                {{.count = 1,
                  .nreg = 1,
                  .ctl_table = root_table,
-                 .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
+                 .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.dir.header.ctl_entry),}},
                .ctl_table_arg = root_table,
                .root = &sysctl_table_root,
                .set = &sysctl_table_root.default_set,
@@ -79,15 +79,12 @@ static int namecmp(const char *name1, int len1, const char *name2, int len2)
 static struct ctl_table *find_entry(struct ctl_table_header **phead,
        struct ctl_dir *dir, const char *name, int namelen)
 {
-       struct ctl_table_set *set = dir->header.set;
        struct ctl_table_header *head;
        struct ctl_table *entry;
 
-       list_for_each_entry(head, &set->list, ctl_entry) {
+       list_for_each_entry(head, &dir->list, ctl_entry) {
                if (head->unregistering)
                        continue;
-               if (head->parent != dir)
-                       continue;
                for (entry = head->ctl_table; entry->procname; entry++) {
                        const char *procname = entry->procname;
                        if (namecmp(procname, strlen(procname), name, namelen) == 0) {
@@ -133,7 +130,7 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
        err = insert_links(header);
        if (err)
                goto fail_links;
-       list_add_tail(&header->ctl_entry, &header->set->list);
+       list_add_tail(&header->ctl_entry, &header->parent->list);
        return 0;
 fail_links:
        header->parent = NULL;
@@ -247,14 +244,12 @@ static struct ctl_table *lookup_entry(struct ctl_table_header **phead,
 static struct ctl_table_header *next_usable_entry(struct ctl_dir *dir,
                                                  struct list_head *tmp)
 {
-       struct ctl_table_set *set = dir->header.set;
        struct ctl_table_header *head;
 
-       for (tmp = tmp->next; tmp != &set->list; tmp = tmp->next) {
+       for (tmp = tmp->next; tmp != &dir->list; tmp = tmp->next) {
                head = list_entry(tmp, struct ctl_table_header, ctl_entry);
 
-               if (head->parent != dir ||
-                   !head->ctl_table->procname ||
+               if (!head->ctl_table->procname ||
                    !use_table(head))
                        continue;
 
@@ -270,7 +265,7 @@ static void first_entry(struct ctl_dir *dir,
        struct ctl_table *entry = NULL;
 
        spin_lock(&sysctl_lock);
-       head = next_usable_entry(dir, &dir->header.set->list);
+       head = next_usable_entry(dir, &dir->list);
        spin_unlock(&sysctl_lock);
        if (head)
                entry = head->ctl_table;
@@ -793,6 +788,7 @@ static struct ctl_dir *new_dir(struct ctl_table_set *set,
        new_name = (char *)(table + 2);
        memcpy(new_name, name, namelen);
        new_name[namelen] = '\0';
+       INIT_LIST_HEAD(&new->list);
        table[0].procname = new_name;
        table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
        init_header(&new->header, set->dir.header.root, set, table);
@@ -917,12 +913,10 @@ static int sysctl_check_table_dups(struct ctl_dir *dir, struct ctl_table *old,
 
 static int sysctl_check_dups(struct ctl_dir *dir, struct ctl_table *table)
 {
-       struct ctl_table_set *set;
        struct ctl_table_header *head;
        int error = 0;
 
-       set = dir->header.set;
-       list_for_each_entry(head, &set->list, ctl_entry) {
+       list_for_each_entry(head, &dir->list, ctl_entry) {
                if (head->unregistering)
                        continue;
                if (head->parent != dir)
@@ -1494,14 +1488,14 @@ void setup_sysctl_set(struct ctl_table_set *set,
        int (*is_seen)(struct ctl_table_set *))
 {
        memset(set, sizeof(*set), 0);
-       INIT_LIST_HEAD(&set->list);
        set->is_seen = is_seen;
+       INIT_LIST_HEAD(&set->dir.list);
        init_header(&set->dir.header, root, set, root_table);
 }
 
 void retire_sysctl_set(struct ctl_table_set *set)
 {
-       WARN_ON(!list_empty(&set->list));
+       WARN_ON(!list_empty(&set->dir.list));
 }
 
 int __init proc_sys_init(void)

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index cec59415b3ce37068bc9cb8cec2bb36abba08863..36dec756ef9dabd2e3e521a9a5e6d4f99b1efae5 100644 (file)
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -1047,10 +1047,10 @@ struct ctl_table_header
 struct ctl_dir {
        /* Header must be at the start of ctl_dir */
        struct ctl_table_header header;
+       struct list_head list;
 };
 
 struct ctl_table_set {
-       struct list_head list;
        int (*is_seen)(struct ctl_table_set *);
        struct ctl_dir dir;
 };