The patch titled
Subject: proc: use slower rb_first()
has been added to the -mm tree. Its filename is
proc-use-slower-rb_first.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-use-slower-rb_first.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-use-slower-rb_first.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: proc: use slower rb_first()
In a typical for /proc "open+read+close" usecase, dentry is looked up
successfully on open only to be killed in dput() on close. In fact
dentries which aren't /proc/*/... and /proc/sys/* were almost NEVER
CACHED. Simple printk in proc_lookup_de() shows that.
Now that ->delete hook intelligently picks which dentries should live in
dcache and which should not, rbtree caching is not necessary as dcache
does it job, at last!
As a side effect, struct proc_dir_entry shrinks by one pointer which can
go into inline name.
Link: http://lkml.kernel.org/r/20180314231032.GA15854@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/generic.c | 26 ++++++++++++--------------
fs/proc/internal.h | 6 +++---
fs/proc/proc_net.c | 2 +-
fs/proc/root.c | 2 +-
4 files changed, 17 insertions(+), 19 deletions(-)
diff -puN fs/proc/generic.c~proc-use-slower-rb_first fs/proc/generic.c
--- a/fs/proc/generic.c~proc-use-slower-rb_first
+++ a/fs/proc/generic.c
@@ -53,8 +53,8 @@ static int proc_match(const char *name,
static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
{
- return rb_entry_safe(rb_first_cached(&dir->subdir),
- struct proc_dir_entry, subdir_node);
+ return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
+ subdir_node);
}
static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
@@ -67,7 +67,7 @@ static struct proc_dir_entry *pde_subdir
const char *name,
unsigned int len)
{
- struct rb_node *node = dir->subdir.rb_root.rb_node;
+ struct rb_node *node = dir->subdir.rb_node;
while (node) {
struct proc_dir_entry *de = rb_entry(node,
@@ -88,9 +88,8 @@ static struct proc_dir_entry *pde_subdir
static bool pde_subdir_insert(struct proc_dir_entry *dir,
struct proc_dir_entry *de)
{
- struct rb_root_cached *root = &dir->subdir;
- struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
- bool leftmost = true;
+ struct rb_root *root = &dir->subdir;
+ struct rb_node **new = &root->rb_node, *parent = NULL;
/* Figure out where to put new node */
while (*new) {
@@ -102,16 +101,15 @@ static bool pde_subdir_insert(struct pro
parent = *new;
if (result < 0)
new = &(*new)->rb_left;
- else if (result > 0) {
+ else if (result > 0)
new = &(*new)->rb_right;
- leftmost = false;
- } else
+ else
return false;
}
/* Add new node and rebalance tree. */
rb_link_node(&de->subdir_node, parent, new);
- rb_insert_color_cached(&de->subdir_node, root, leftmost);
+ rb_insert_color(&de->subdir_node, root);
return true;
}
@@ -422,7 +420,7 @@ static struct proc_dir_entry *__proc_cre
ent->namelen = qstr.len;
ent->mode = mode;
ent->nlink = nlink;
- ent->subdir = RB_ROOT_CACHED;
+ ent->subdir = RB_ROOT;
refcount_set(&ent->refcnt, 1);
spin_lock_init(&ent->pde_unload_lock);
INIT_LIST_HEAD(&ent->pde_openers);
@@ -598,7 +596,7 @@ void remove_proc_entry(const char *name,
de = pde_subdir_find(parent, fn, len);
if (de)
- rb_erase_cached(&de->subdir_node, &parent->subdir);
+ rb_erase(&de->subdir_node, &parent->subdir);
write_unlock(&proc_subdir_lock);
if (!de) {
WARN(1, "name '%s'\n", name);
@@ -635,13 +633,13 @@ int remove_proc_subtree(const char *name
write_unlock(&proc_subdir_lock);
return -ENOENT;
}
- rb_erase_cached(&root->subdir_node, &parent->subdir);
+ rb_erase(&root->subdir_node, &parent->subdir);
de = root;
while (1) {
next = pde_subdir_first(de);
if (next) {
- rb_erase_cached(&next->subdir_node, &de->subdir);
+ rb_erase(&next->subdir_node, &de->subdir);
de = next;
continue;
}
diff -puN fs/proc/internal.h~proc-use-slower-rb_first fs/proc/internal.h
--- a/fs/proc/internal.h~proc-use-slower-rb_first
+++ a/fs/proc/internal.h
@@ -51,15 +51,15 @@ struct proc_dir_entry {
kgid_t gid;
loff_t size;
struct proc_dir_entry *parent;
- struct rb_root_cached subdir;
+ struct rb_root subdir;
struct rb_node subdir_node;
char *name;
umode_t mode;
u8 namelen;
#ifdef CONFIG_64BIT
-#define SIZEOF_PDE_INLINE_NAME (192-147)
+#define SIZEOF_PDE_INLINE_NAME (192-139)
#else
-#define SIZEOF_PDE_INLINE_NAME (128-91)
+#define SIZEOF_PDE_INLINE_NAME (128-87)
#endif
char inline_name[SIZEOF_PDE_INLINE_NAME];
} __randomize_layout;
diff -puN fs/proc/proc_net.c~proc-use-slower-rb_first fs/proc/proc_net.c
--- a/fs/proc/proc_net.c~proc-use-slower-rb_first
+++ a/fs/proc/proc_net.c
@@ -196,7 +196,7 @@ static __net_init int proc_net_ns_init(s
if (!netd)
goto out;
- netd->subdir = RB_ROOT_CACHED;
+ netd->subdir = RB_ROOT;
netd->data = net;
netd->nlink = 2;
netd->namelen = 3;
diff -puN fs/proc/root.c~proc-use-slower-rb_first fs/proc/root.c
--- a/fs/proc/root.c~proc-use-slower-rb_first
+++ a/fs/proc/root.c
@@ -203,7 +203,7 @@ struct proc_dir_entry proc_root = {
.proc_iops = &proc_root_inode_operations,
.proc_fops = &proc_root_operations,
.parent = &proc_root,
- .subdir = RB_ROOT_CACHED,
+ .subdir = RB_ROOT,
.name = proc_root.inline_name,
.inline_name = "/proc",
};
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
slab-mark-kmalloc-machinery-as-__ro_after_init.patch
slab-fixup-calculate_alignment-argument-type.patch
slab-make-kmalloc_index-return-unsigned-int.patch
slab-make-kmalloc_size-return-unsigned-int.patch
slab-make-create_kmalloc_cache-work-with-32-bit-sizes.patch
slab-make-create_boot_cache-work-with-32-bit-sizes.patch
slab-make-kmem_cache_create-work-with-32-bit-sizes.patch
slab-make-size_index-array-u8.patch
slab-make-size_index_elem-unsigned-int.patch
slub-make-remote_node_defrag_ratio-unsigned-int.patch
slub-make-max_attr_size-unsigned-int.patch
slub-make-red_left_pad-unsigned-int.patch
slub-make-reserved-unsigned-int.patch
slub-make-align-unsigned-int.patch
slub-make-inuse-unsigned-int.patch
slub-make-cpu_partial-unsigned-int.patch
slub-make-offset-unsigned-int.patch
slub-make-object_size-unsigned-int.patch
slub-make-size-unsigned-int.patch
slab-make-kmem_cache_flags-accept-32-bit-object-size.patch
kasan-make-kasan_cache_create-work-with-32-bit-slab-cache-sizes.patch
slab-make-usercopy-region-32-bit.patch
slub-make-slab_index-return-unsigned-int.patch
slub-make-struct-kmem_cache_order_objects-x-unsigned-int.patch
slub-make-size_from_object-return-unsigned-int.patch
slab-use-32-bit-arithmetic-in-freelist_randomize.patch
proc-do-less-stuff-under-pde_unload_lock.patch
proc-move-proc-sysvipc-creation-to-where-it-belongs.patch
proc-faster-open-close-of-files-without-release-hook.patch
proc-randomize-struct-pde_opener.patch
proc-move-struct-pde_opener-to-kmem-cache.patch
proc-account-struct-pde_opener.patch
proc-check-permissions-earlier-for-proc-wchan.patch
proc-use-set_puts-at-proc-wchan.patch
proc-test-proc-self-wchan.patch
proc-test-proc-self-syscall.patch
proc-move-struct-proc_dir_entry-into-kmem-cache.patch
proc-fix-proc-map_files-lookup-some-more.patch
proc-register-filesystem-last.patch
proc-faster-proc-cmdline.patch
proc-do-mmput-asap-for-proc-map_files.patch
proc-revalidate-misc-dentries.patch
proc-test-last-field-of-proc-loadavg.patch
proc-reject-and-as-filenames.patch
proc-switch-struct-proc_dir_entry-count-to-refcount.patch
proc-shotgun-test-read-readdir-readlink-a-little-write.patch
proc-use-slower-rb_first.patch
uts-create-struct-uts_namespace-from-kmem_cache.patch
seq_file-allocate-seq_file-from-kmem_cache.patch
seq_file-account-everything.patch
seq_file-delete-small-value-optimization.patch
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