fscache, cachefiles: Remove the histogram stuff

Remove the histogram stuff as it's mostly going to be outdated.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431195953.2908479.16770977195634296638.stgit@warthog.procyon.org.uk/

6 files changed, 0 insertions, 180 deletions

diff --git a/fs/cachefiles/Kconfig b/fs/cachefiles/Kconfig
index ff9ca55a9ae9..6827b40f7ddc 100644
--- a/fs/cachefiles/Kconfig
+++ b/fs/cachefiles/Kconfig
@@ -19,22 +19,3 @@ config CACHEFILES_DEBUG
 	  caching on files module.  If this is set, the debugging output may be
 	  enabled by setting bits in /sys/modules/cachefiles/parameter/debug or
 	  by including a debugging specifier in /etc/cachefilesd.conf.
-
-config CACHEFILES_HISTOGRAM
-	bool "Gather latency information on CacheFiles"
-	depends on CACHEFILES && PROC_FS
-	help
-
-	  This option causes latency information to be gathered on CacheFiles
-	  operation and exported through file:
-
-		/proc/fs/cachefiles/histogram
-
-	  The generation of this histogram adds a certain amount of overhead to
-	  execution as there are a number of points at which data is gathered,
-	  and on a multi-CPU system these may be on cachelines that keep
-	  bouncing between CPUs.  On the other hand, the histogram may be
-	  useful for debugging purposes.  Saying 'N' here is recommended.
-
-	  See Documentation/filesystems/caching/cachefiles.rst for more
-	  information.
diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile
index 2227dc2d5498..02fd17731769 100644
--- a/fs/cachefiles/Makefile
+++ b/fs/cachefiles/Makefile
@@ -15,6 +15,4 @@ cachefiles-y := \
 	security.o \
 	xattr.o
 
-cachefiles-$(CONFIG_CACHEFILES_HISTOGRAM) += proc.o
-
 obj-$(CONFIG_CACHEFILES) := cachefiles.o
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 4ed83aa5253b..0a511c36dab8 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -181,31 +181,6 @@ extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
 				   struct dentry *dir, char *filename);
 
 /*
- * proc.c
- */
-#ifdef CONFIG_CACHEFILES_HISTOGRAM
-extern atomic_t cachefiles_lookup_histogram[HZ];
-extern atomic_t cachefiles_mkdir_histogram[HZ];
-extern atomic_t cachefiles_create_histogram[HZ];
-
-extern int __init cachefiles_proc_init(void);
-extern void cachefiles_proc_cleanup(void);
-static inline
-void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
-{
-	unsigned long jif = jiffies - start_jif;
-	if (jif >= HZ)
-		jif = HZ - 1;
-	atomic_inc(&histogram[jif]);
-}
-
-#else
-#define cachefiles_proc_init()		(0)
-#define cachefiles_proc_cleanup()	do {} while (0)
-#define cachefiles_hist(hist, start_jif) do {} while (0)
-#endif
-
-/*
  * rdwr.c
  */
 extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
diff --git a/fs/cachefiles/main.c b/fs/cachefiles/main.c
index ddf0cd58d60c..9c8d34c49b12 100644
--- a/fs/cachefiles/main.c
+++ b/fs/cachefiles/main.c
@@ -69,15 +69,9 @@ static int __init cachefiles_init(void)
 		goto error_object_jar;
 	}
 
-	ret = cachefiles_proc_init();
-	if (ret < 0)
-		goto error_proc;
-
 	pr_info("Loaded\n");
 	return 0;
 
-error_proc:
-	kmem_cache_destroy(cachefiles_object_jar);
 error_object_jar:
 	misc_deregister(&cachefiles_dev);
 error_dev:
@@ -94,7 +88,6 @@ static void __exit cachefiles_exit(void)
 {
 	pr_info("Unloading\n");
 
-	cachefiles_proc_cleanup();
 	kmem_cache_destroy(cachefiles_object_jar);
 	misc_deregister(&cachefiles_dev);
 }
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 7bf0732ae25c..92aa550dae7e 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -496,7 +496,6 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent,
 	struct dentry *dir, *next = NULL;
 	struct inode *inode;
 	struct path path;
-	unsigned long start;
 	const char *name;
 	int ret, nlen;
 
@@ -535,9 +534,7 @@ lookup_again:
 
 	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
 
-	start = jiffies;
 	next = lookup_one_len(name, dir, nlen);
-	cachefiles_hist(cachefiles_lookup_histogram, start);
 	if (IS_ERR(next)) {
 		trace_cachefiles_lookup(object, next, NULL);
 		goto lookup_error;
@@ -568,9 +565,7 @@ lookup_again:
 			ret = security_path_mkdir(&path, next, 0);
 			if (ret < 0)
 				goto create_error;
-			start = jiffies;
 			ret = vfs_mkdir(&init_user_ns, d_inode(dir), next, 0);
-			cachefiles_hist(cachefiles_mkdir_histogram, start);
 			if (!key)
 				trace_cachefiles_mkdir(object, next, ret);
 			if (ret < 0)
@@ -604,10 +599,8 @@ lookup_again:
 			ret = security_path_mknod(&path, next, S_IFREG, 0);
 			if (ret < 0)
 				goto create_error;
-			start = jiffies;
 			ret = vfs_create(&init_user_ns, d_inode(dir), next,
 					 S_IFREG, true);
-			cachefiles_hist(cachefiles_create_histogram, start);
 			trace_cachefiles_create(object, next, ret);
 			if (ret < 0)
 				goto create_error;
@@ -765,7 +758,6 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 					const char *dirname)
 {
 	struct dentry *subdir;
-	unsigned long start;
 	struct path path;
 	int ret;
 
@@ -775,9 +767,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 	inode_lock(d_inode(dir));
 
 retry:
-	start = jiffies;
 	subdir = lookup_one_len(dirname, dir, strlen(dirname));
-	cachefiles_hist(cachefiles_lookup_histogram, start);
 	if (IS_ERR(subdir)) {
 		if (PTR_ERR(subdir) == -ENOMEM)
 			goto nomem_d_alloc;
@@ -876,7 +866,6 @@ static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
 	struct cachefiles_object *object;
 	struct rb_node *_n;
 	struct dentry *victim;
-	unsigned long start;
 	int ret;
 
 	//_enter(",%pd/,%s",
@@ -885,9 +874,7 @@ static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
 	/* look up the victim */
 	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
 
-	start = jiffies;
 	victim = lookup_one_len(filename, dir, strlen(filename));
-	cachefiles_hist(cachefiles_lookup_histogram, start);
 	if (IS_ERR(victim))
 		goto lookup_error;
 
diff --git a/fs/cachefiles/proc.c b/fs/cachefiles/proc.c
deleted file mode 100644
index 6e67aea0f24e..000000000000
--- a/fs/cachefiles/proc.c
+++ /dev/null
@@ -1,114 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* CacheFiles statistics
- *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
-
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include "internal.h"
-
-atomic_t cachefiles_lookup_histogram[HZ];
-atomic_t cachefiles_mkdir_histogram[HZ];
-atomic_t cachefiles_create_histogram[HZ];
-
-/*
- * display the latency histogram
- */
-static int cachefiles_histogram_show(struct seq_file *m, void *v)
-{
-	unsigned long index;
-	unsigned x, y, z, t;
-
-	switch ((unsigned long) v) {
-	case 1:
-		seq_puts(m, "JIFS  SECS  LOOKUPS   MKDIRS    CREATES\n");
-		return 0;
-	case 2:
-		seq_puts(m, "===== ===== ========= ========= =========\n");
-		return 0;
-	default:
-		index = (unsigned long) v - 3;
-		x = atomic_read(&cachefiles_lookup_histogram[index]);
-		y = atomic_read(&cachefiles_mkdir_histogram[index]);
-		z = atomic_read(&cachefiles_create_histogram[index]);
-		if (x == 0 && y == 0 && z == 0)
-			return 0;
-
-		t = (index * 1000) / HZ;
-
-		seq_printf(m, "%4lu  0.%03u %9u %9u %9u\n", index, t, x, y, z);
-		return 0;
-	}
-}
-
-/*
- * set up the iterator to start reading from the first line
- */
-static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos)
-{
-	if ((unsigned long long)*_pos >= HZ + 2)
-		return NULL;
-	if (*_pos == 0)
-		*_pos = 1;
-	return (void *)(unsigned long) *_pos;
-}
-
-/*
- * move to the next line
- */
-static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	(*pos)++;
-	return (unsigned long long)*pos > HZ + 2 ?
-		NULL : (void *)(unsigned long) *pos;
-}
-
-/*
- * clean up after reading
- */
-static void cachefiles_histogram_stop(struct seq_file *m, void *v)
-{
-}
-
-static const struct seq_operations cachefiles_histogram_ops = {
-	.start		= cachefiles_histogram_start,
-	.stop		= cachefiles_histogram_stop,
-	.next		= cachefiles_histogram_next,
-	.show		= cachefiles_histogram_show,
-};
-
-/*
- * initialise the /proc/fs/cachefiles/ directory
- */
-int __init cachefiles_proc_init(void)
-{
-	_enter("");
-
-	if (!proc_mkdir("fs/cachefiles", NULL))
-		goto error_dir;
-
-	if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
-			 &cachefiles_histogram_ops))
-		goto error_histogram;
-
-	_leave(" = 0");
-	return 0;
-
-error_histogram:
-	remove_proc_entry("fs/cachefiles", NULL);
-error_dir:
-	_leave(" = -ENOMEM");
-	return -ENOMEM;
-}
-
-/*
- * clean up the /proc/fs/cachefiles/ directory
- */
-void cachefiles_proc_cleanup(void)
-{
-	remove_proc_entry("fs/cachefiles/histogram", NULL);
-	remove_proc_entry("fs/cachefiles", NULL);
-}