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Date: Sun, 17 May 2009 15:55:12 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: Wu Fengguang <fengguang.wu@...el.com>
Cc: Ingo Molnar <mingo@...e.hu>, Li Zefan <lizf@...fujitsu.com>,
Tom Zanussi <tzanussi@...il.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Pekka Enberg <penberg@...helsinki.fi>,
Andi Kleen <andi@...stfloor.org>,
Steven Rostedt <rostedt@...dmis.org>,
Larry Woodman <lwoodman@...hat.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Eduard - Gabriel Munteanu <eduard.munteanu@...ux360.ro>,
Andrew Morton <akpm@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>,
Matt Mackall <mpm@...enic.com>,
Alexey Dobriyan <adobriyan@...il.com>,
"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [rfc] object collection tracing (was: [PATCH 5/5] proc: export
more page flags in /proc/kpageflags)
On Sun, May 17, 2009 at 09:36:59PM +0800, Wu Fengguang wrote:
> On Tue, May 12, 2009 at 09:01:12PM +0800, Frederic Weisbecker wrote:
> > On Tue, Apr 28, 2009 at 09:31:08PM +0800, Wu Fengguang wrote:
> > > On Tue, Apr 28, 2009 at 08:17:51PM +0800, Ingo Molnar wrote:
> > >
> > > There are two possible challenges for the conversion:
> > >
> > > - One trick it does is to select different lists to traverse on
> > > different filter options. Will this be possible in the object
> > > tracing framework?
> >
> > Yeah, I guess.
>
> Great.
>
> >
> > > - The file name lookup(last field) is the performance killer. Is it
> > > possible to skip the file name lookup when the filter failed on the
> > > leading fields?
> >
> > objects collection lays on trace events where filters basically ignore
> > a whole entry in case of non-matching. Not sure if we can easily only
> > ignore one field.
> >
> > But I guess we can do something about the performances...
>
> OK, but it's not as important as the previous requirement, so it could
> be the last thing to work on :)
>
> > Could you send us the (sob'ed) patch you made which implements this.
> > I could try to adapt it to object collection.
>
> Attached for your reference. Be aware that I still have plans to
> change it in non trivial way, and there are ongoing works by Nick(on
> inode_lock) and Jens(on s_dirty) that can create merge conflicts.
> So basically it is not a right time to do the adaption.
Ah ok, so I will wait a bit :-)
> However we can still do something to polish up the page object
> collection under /debug/tracing/objects/mm/pages/. For example,
> the timestamps and function name could be removed from the following
> list :)
>
> # tracer: nop
> #
> # TASK-PID CPU# TIMESTAMP FUNCTION
> # | | | | |
> <...>-3743 [001] 3035.649769: dump_pages: pfn=1 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176403: dump_pages: pfn=1 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176407: dump_pages: pfn=2 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176408: dump_pages: pfn=3 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176409: dump_pages: pfn=4 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176409: dump_pages: pfn=5 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176410: dump_pages: pfn=6 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176410: dump_pages: pfn=7 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176411: dump_pages: pfn=8 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176411: dump_pages: pfn=9 flags=400 count=1 mapcount=0 index=0
> <...>-3743 [001] 3044.176412: dump_pages: pfn=10 flags=400 count=1 mapcount=0 index=0
echo nocontext-info > /debug/tracing/trace_options :-)
But you'll have only the function and the pages specifics. It's not really the
function but more specifically the name of the event. It's useful to distinguish
multiple events to a trace.
Hmm, may be it's not that much useful in a object dump...
Thanks.
> Thanks,
> Fengguang
> --- linux-2.6.orig/include/linux/mm.h
> +++ linux-2.6/include/linux/mm.h
> @@ -27,6 +27,7 @@ extern unsigned long max_mapnr;
> extern unsigned long num_physpages;
> extern void * high_memory;
> extern int page_cluster;
> +extern char * const zone_names[];
>
> #ifdef CONFIG_SYSCTL
> extern int sysctl_legacy_va_layout;
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -104,7 +104,7 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_Z
>
> EXPORT_SYMBOL(totalram_pages);
>
> -static char * const zone_names[MAX_NR_ZONES] = {
> +char * const zone_names[MAX_NR_ZONES] = {
> #ifdef CONFIG_ZONE_DMA
> "DMA",
> #endif
> --- linux-2.6.orig/fs/dcache.c
> +++ linux-2.6/fs/dcache.c
> @@ -1925,7 +1925,10 @@ char *__d_path(const struct path *path,
>
> if (dentry == root->dentry && vfsmnt == root->mnt)
> break;
> - if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
> + if (unlikely(!vfsmnt)) {
> + if (IS_ROOT(dentry))
> + break;
> + } else if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
> /* Global root? */
> if (vfsmnt->mnt_parent == vfsmnt) {
> goto global_root;
> --- linux-2.6.orig/lib/radix-tree.c
> +++ linux-2.6/lib/radix-tree.c
> @@ -564,7 +564,6 @@ out:
> }
> EXPORT_SYMBOL(radix_tree_tag_clear);
>
> -#ifndef __KERNEL__ /* Only the test harness uses this at present */
> /**
> * radix_tree_tag_get - get a tag on a radix tree node
> * @root: radix tree root
> @@ -627,7 +626,6 @@ int radix_tree_tag_get(struct radix_tree
> }
> }
> EXPORT_SYMBOL(radix_tree_tag_get);
> -#endif
>
> /**
> * radix_tree_next_hole - find the next hole (not-present entry)
> --- linux-2.6.orig/fs/inode.c
> +++ linux-2.6/fs/inode.c
> @@ -84,6 +84,10 @@ static struct hlist_head *inode_hashtabl
> */
> DEFINE_SPINLOCK(inode_lock);
>
> +EXPORT_SYMBOL(inode_in_use);
> +EXPORT_SYMBOL(inode_unused);
> +EXPORT_SYMBOL(inode_lock);
> +
> /*
> * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
> * icache shrinking path, and the umount path. Without this exclusion,
> @@ -110,6 +114,13 @@ static void wake_up_inode(struct inode *
> wake_up_bit(&inode->i_state, __I_LOCK);
> }
>
> +static inline void inode_created_by(struct inode *inode, struct task_struct *task)
> +{
> +#ifdef CONFIG_PROC_FILECACHE_EXTRAS
> + memcpy(inode->i_comm, task->comm, sizeof(task->comm));
> +#endif
> +}
> +
> /**
> * inode_init_always - perform inode structure intialisation
> * @sb: superblock inode belongs to
> @@ -147,7 +158,7 @@ struct inode *inode_init_always(struct s
> inode->i_bdev = NULL;
> inode->i_cdev = NULL;
> inode->i_rdev = 0;
> - inode->dirtied_when = 0;
> + inode->dirtied_when = jiffies;
>
> if (security_inode_alloc(inode))
> goto out_free_inode;
> @@ -188,6 +199,7 @@ struct inode *inode_init_always(struct s
> }
> inode->i_private = NULL;
> inode->i_mapping = mapping;
> + inode_created_by(inode, current);
>
> return inode;
>
> @@ -276,6 +288,8 @@ void __iget(struct inode *inode)
> inodes_stat.nr_unused--;
> }
>
> +EXPORT_SYMBOL(__iget);
> +
> /**
> * clear_inode - clear an inode
> * @inode: inode to clear
> @@ -1459,6 +1473,16 @@ static void __wait_on_freeing_inode(stru
> spin_lock(&inode_lock);
> }
>
> +
> +struct hlist_head * get_inode_hash_budget(unsigned long index)
> +{
> + if (index >= (1 << i_hash_shift))
> + return NULL;
> +
> + return inode_hashtable + index;
> +}
> +EXPORT_SYMBOL_GPL(get_inode_hash_budget);
> +
> static __initdata unsigned long ihash_entries;
> static int __init set_ihash_entries(char *str)
> {
> --- linux-2.6.orig/fs/super.c
> +++ linux-2.6/fs/super.c
> @@ -46,6 +46,9 @@
> LIST_HEAD(super_blocks);
> DEFINE_SPINLOCK(sb_lock);
>
> +EXPORT_SYMBOL(super_blocks);
> +EXPORT_SYMBOL(sb_lock);
> +
> /**
> * alloc_super - create new superblock
> * @type: filesystem type superblock should belong to
> --- linux-2.6.orig/mm/vmscan.c
> +++ linux-2.6/mm/vmscan.c
> @@ -262,6 +262,7 @@ unsigned long shrink_slab(unsigned long
> up_read(&shrinker_rwsem);
> return ret;
> }
> +EXPORT_SYMBOL(shrink_slab);
>
> /* Called without lock on whether page is mapped, so answer is unstable */
> static inline int page_mapping_inuse(struct page *page)
> --- linux-2.6.orig/mm/swap_state.c
> +++ linux-2.6/mm/swap_state.c
> @@ -45,6 +45,7 @@ struct address_space swapper_space = {
> .i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear),
> .backing_dev_info = &swap_backing_dev_info,
> };
> +EXPORT_SYMBOL_GPL(swapper_space);
>
> #define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0)
>
> --- linux-2.6.orig/Documentation/filesystems/proc.txt
> +++ linux-2.6/Documentation/filesystems/proc.txt
> @@ -260,6 +260,7 @@ Table 1-4: Kernel info in /proc
> driver Various drivers grouped here, currently rtc (2.4)
> execdomains Execdomains, related to security (2.4)
> fb Frame Buffer devices (2.4)
> + filecache Query/drop in-memory file cache
> fs File system parameters, currently nfs/exports (2.4)
> ide Directory containing info about the IDE subsystem
> interrupts Interrupt usage
> @@ -450,6 +451,88 @@ varies by architecture and compile optio
>
> > cat /proc/meminfo
>
> +..............................................................................
> +
> +filecache:
> +
> +Provides access to the in-memory file cache.
> +
> +To list an index of all cached files:
> +
> + echo ls > /proc/filecache
> + cat /proc/filecache
> +
> +The output looks like:
> +
> + # filecache 1.0
> + # ino size cached cached% state refcnt dev file
> + 1026334 91 92 100 -- 66 03:02(hda2) /lib/ld-2.3.6.so
> + 233608 1242 972 78 -- 66 03:02(hda2) /lib/tls/libc-2.3.6.so
> + 65203 651 476 73 -- 1 03:02(hda2) /bin/bash
> + 1026445 261 160 61 -- 10 03:02(hda2) /lib/libncurses.so.5.5
> + 235427 10 12 100 -- 44 03:02(hda2) /lib/tls/libdl-2.3.6.so
> +
> +FIELD INTRO
> +---------------------------------------------------------------------------
> +ino inode number
> +size inode size in KB
> +cached cached size in KB
> +cached% percent of file data cached
> +state1 '-' clean; 'd' metadata dirty; 'D' data dirty
> +state2 '-' unlocked; 'L' locked, normally indicates file being written out
> +refcnt file reference count, it's an in-kernel one, not exactly open count
> +dev major:minor numbers in hex, followed by a descriptive device name
> +file file path _inside_ the filesystem. There are several special names:
> + '(noname)': the file name is not available
> + '(03:02)': the file is a block device file of major:minor
> + '...(deleted)': the named file has been deleted from the disk
> +
> +To list the cached pages of a perticular file:
> +
> + echo /bin/bash > /proc/filecache
> + cat /proc/filecache
> +
> + # file /bin/bash
> + # flags R:referenced A:active U:uptodate D:dirty W:writeback M:mmap
> + # idx len state refcnt
> + 0 36 RAU__M 3
> + 36 1 RAU__M 2
> + 37 8 RAU__M 3
> + 45 2 RAU___ 1
> + 47 6 RAU__M 3
> + 53 3 RAU__M 2
> + 56 2 RAU__M 3
> +
> +FIELD INTRO
> +----------------------------------------------------------------------------
> +idx page index
> +len number of pages which are cached and share the same state
> +state page state of the flags listed in line two
> +refcnt page reference count
> +
> +Careful users may notice that the file name to be queried is remembered between
> +commands. Internally, the module has a global variable to store the file name
> +parameter, so that it can be inherited by newly opened /proc/filecache file.
> +However it can lead to interference for multiple queriers. The solution here
> +is to obey a rule: only root can interactively change the file name parameter;
> +normal users must go for scripts to access the interface. Scripts should do it
> +by following the code example below:
> +
> + filecache = open("/proc/filecache", "rw");
> + # avoid polluting the global parameter filename
> + filecache.write("set private");
> +
> +To instruct the kernel to drop clean caches, dentries and inodes from memory,
> +causing that memory to become free:
> +
> + # drop clean file data cache (i.e. file backed pagecache)
> + echo drop pagecache > /proc/filecache
> +
> + # drop clean file metadata cache (i.e. dentries and inodes)
> + echo drop slabcache > /proc/filecache
> +
> +Note that the drop commands are non-destructive operations and dirty objects
> +are not freeable, the user should run `sync' first.
>
> MemTotal: 16344972 kB
> MemFree: 13634064 kB
> --- /dev/null
> +++ linux-2.6/fs/proc/filecache.c
> @@ -0,0 +1,1045 @@
> +/*
> + * fs/proc/filecache.c
> + *
> + * Copyright (C) 2006, 2007 Fengguang Wu <wfg@...l.ustc.edu.cn>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/fs.h>
> +#include <linux/mm.h>
> +#include <linux/radix-tree.h>
> +#include <linux/page-flags.h>
> +#include <linux/pagevec.h>
> +#include <linux/pagemap.h>
> +#include <linux/vmalloc.h>
> +#include <linux/writeback.h>
> +#include <linux/buffer_head.h>
> +#include <linux/parser.h>
> +#include <linux/proc_fs.h>
> +#include <linux/seq_file.h>
> +#include <linux/file.h>
> +#include <linux/namei.h>
> +#include <linux/module.h>
> +#include <asm/uaccess.h>
> +
> +/*
> + * Increase minor version when new columns are added;
> + * Increase major version when existing columns are changed.
> + */
> +#define FILECACHE_VERSION "1.0"
> +
> +/* Internal buffer sizes. The larger the more effcient. */
> +#define SBUF_SIZE (128<<10)
> +#define IWIN_PAGE_ORDER 3
> +#define IWIN_SIZE ((PAGE_SIZE<<IWIN_PAGE_ORDER) / sizeof(struct inode *))
> +
> +/*
> + * Session management.
> + *
> + * Each opened /proc/filecache file is assiocated with a session object.
> + * Also there is a global_session that maintains status across open()/close()
> + * (i.e. the lifetime of an opened file), so that a casual user can query the
> + * filecache via _multiple_ simple shell commands like
> + * 'echo cat /bin/bash > /proc/filecache; cat /proc/filecache'.
> + *
> + * session.query_file is the file whose cache info is to be queried.
> + * Its value determines what we get on read():
> + * - NULL: ii_*() called to show the inode index
> + * - filp: pg_*() called to show the page groups of a filp
> + *
> + * session.query_file is
> + * - cloned from global_session.query_file on open();
> + * - updated on write("cat filename");
> + * note that the new file will also be saved in global_session.query_file if
> + * session.private_session is false.
> + */
> +
> +struct session {
> + /* options */
> + int private_session;
> + unsigned long ls_options;
> + dev_t ls_dev;
> +
> + /* parameters */
> + struct file *query_file;
> +
> + /* seqfile pos */
> + pgoff_t start_offset;
> + pgoff_t next_offset;
> +
> + /* inode at last pos */
> + struct {
> + unsigned long pos;
> + unsigned long state;
> + struct inode *inode;
> + struct inode *pinned_inode;
> + } ipos;
> +
> + /* inode window */
> + struct {
> + unsigned long cursor;
> + unsigned long origin;
> + unsigned long size;
> + struct inode **inodes;
> + } iwin;
> +};
> +
> +static struct session global_session;
> +
> +/*
> + * Session address is stored in proc_file->f_ra.start:
> + * we assume that there will be no readahead for proc_file.
> + */
> +static struct session *get_session(struct file *proc_file)
> +{
> + return (struct session *)proc_file->f_ra.start;
> +}
> +
> +static void set_session(struct file *proc_file, struct session *s)
> +{
> + BUG_ON(proc_file->f_ra.start);
> + proc_file->f_ra.start = (unsigned long)s;
> +}
> +
> +static void update_global_file(struct session *s)
> +{
> + if (s->private_session)
> + return;
> +
> + if (global_session.query_file)
> + fput(global_session.query_file);
> +
> + global_session.query_file = s->query_file;
> +
> + if (global_session.query_file)
> + get_file(global_session.query_file);
> +}
> +
> +/*
> + * Cases of the name:
> + * 1) NULL (new session)
> + * s->query_file = global_session.query_file = 0;
> + * 2) "" (ls/la)
> + * s->query_file = global_session.query_file;
> + * 3) a regular file name (cat newfile)
> + * s->query_file = global_session.query_file = newfile;
> + */
> +static int session_update_file(struct session *s, char *name)
> +{
> + static DEFINE_MUTEX(mutex); /* protects global_session.query_file */
> + int err = 0;
> +
> + mutex_lock(&mutex);
> +
> + /*
> + * We are to quit, or to list the cached files.
> + * Reset *.query_file.
> + */
> + if (!name) {
> + if (s->query_file) {
> + fput(s->query_file);
> + s->query_file = NULL;
> + }
> + update_global_file(s);
> + goto out;
> + }
> +
> + /*
> + * This is a new session.
> + * Inherit options/parameters from global ones.
> + */
> + if (name[0] == '\0') {
> + *s = global_session;
> + if (s->query_file)
> + get_file(s->query_file);
> + goto out;
> + }
> +
> + /*
> + * Open the named file.
> + */
> + if (s->query_file)
> + fput(s->query_file);
> + s->query_file = filp_open(name, O_RDONLY|O_LARGEFILE, 0);
> + if (IS_ERR(s->query_file)) {
> + err = PTR_ERR(s->query_file);
> + s->query_file = NULL;
> + } else
> + update_global_file(s);
> +
> +out:
> + mutex_unlock(&mutex);
> +
> + return err;
> +}
> +
> +static struct session *session_create(void)
> +{
> + struct session *s;
> + int err = 0;
> +
> + s = kmalloc(sizeof(*s), GFP_KERNEL);
> + if (s)
> + err = session_update_file(s, "");
> + else
> + err = -ENOMEM;
> +
> + return err ? ERR_PTR(err) : s;
> +}
> +
> +static void session_release(struct session *s)
> +{
> + if (s->ipos.pinned_inode)
> + iput(s->ipos.pinned_inode);
> + if (s->query_file)
> + fput(s->query_file);
> + kfree(s);
> +}
> +
> +
> +/*
> + * Listing of cached files.
> + *
> + * Usage:
> + * echo > /proc/filecache # enter listing mode
> + * cat /proc/filecache # get the file listing
> + */
> +
> +/* code style borrowed from ib_srp.c */
> +enum {
> + LS_OPT_ERR = 0,
> + LS_OPT_DIRTY = 1 << 0,
> + LS_OPT_CLEAN = 1 << 1,
> + LS_OPT_INUSE = 1 << 2,
> + LS_OPT_EMPTY = 1 << 3,
> + LS_OPT_ALL = 1 << 4,
> + LS_OPT_DEV = 1 << 5,
> +};
> +
> +static match_table_t ls_opt_tokens = {
> + { LS_OPT_DIRTY, "dirty" },
> + { LS_OPT_CLEAN, "clean" },
> + { LS_OPT_INUSE, "inuse" },
> + { LS_OPT_EMPTY, "empty" },
> + { LS_OPT_ALL, "all" },
> + { LS_OPT_DEV, "dev=%s" },
> + { LS_OPT_ERR, NULL }
> +};
> +
> +static int ls_parse_options(const char *buf, struct session *s)
> +{
> + substring_t args[MAX_OPT_ARGS];
> + char *options, *sep_opt;
> + char *p;
> + int token;
> + int ret = 0;
> +
> + if (!buf)
> + return 0;
> + options = kstrdup(buf, GFP_KERNEL);
> + if (!options)
> + return -ENOMEM;
> +
> + s->ls_options = 0;
> + sep_opt = options;
> + while ((p = strsep(&sep_opt, " ")) != NULL) {
> + if (!*p)
> + continue;
> +
> + token = match_token(p, ls_opt_tokens, args);
> +
> + switch (token) {
> + case LS_OPT_DIRTY:
> + case LS_OPT_CLEAN:
> + case LS_OPT_INUSE:
> + case LS_OPT_EMPTY:
> + case LS_OPT_ALL:
> + s->ls_options |= token;
> + break;
> + case LS_OPT_DEV:
> + p = match_strdup(args);
> + if (!p) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + if (*p == '/') {
> + struct kstat stat;
> + struct nameidata nd;
> + ret = path_lookup(p, LOOKUP_FOLLOW, &nd);
> + if (!ret)
> + ret = vfs_getattr(nd.path.mnt,
> + nd.path.dentry, &stat);
> + if (!ret)
> + s->ls_dev = stat.rdev;
> + } else
> + s->ls_dev = simple_strtoul(p, NULL, 0);
> + /* printk("%lx %s\n", (long)s->ls_dev, p); */
> + kfree(p);
> + break;
> +
> + default:
> + printk(KERN_WARNING "unknown parameter or missing value "
> + "'%s' in ls command\n", p);
> + ret = -EINVAL;
> + goto out;
> + }
> + }
> +
> +out:
> + kfree(options);
> + return ret;
> +}
> +
> +/*
> + * Add possible filters here.
> + * No permission check: we cannot verify the path's permission anyway.
> + * We simply demand root previledge for accessing /proc/filecache.
> + */
> +static int may_show_inode(struct session *s, struct inode *inode)
> +{
> + if (!atomic_read(&inode->i_count))
> + return 0;
> + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
> + return 0;
> + if (!inode->i_mapping)
> + return 0;
> +
> + if (s->ls_dev && s->ls_dev != inode->i_sb->s_dev)
> + return 0;
> +
> + if (s->ls_options & LS_OPT_ALL)
> + return 1;
> +
> + if (!(s->ls_options & LS_OPT_EMPTY) && !inode->i_mapping->nrpages)
> + return 0;
> +
> + if ((s->ls_options & LS_OPT_DIRTY) && !(inode->i_state & I_DIRTY))
> + return 0;
> +
> + if ((s->ls_options & LS_OPT_CLEAN) && (inode->i_state & I_DIRTY))
> + return 0;
> +
> + if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> + S_ISLNK(inode->i_mode) || S_ISBLK(inode->i_mode)))
> + return 0;
> +
> + return 1;
> +}
> +
> +/*
> + * Full: there are more data following.
> + */
> +static int iwin_full(struct session *s)
> +{
> + return !s->iwin.cursor ||
> + s->iwin.cursor > s->iwin.origin + s->iwin.size;
> +}
> +
> +static int iwin_push(struct session *s, struct inode *inode)
> +{
> + if (!may_show_inode(s, inode))
> + return 0;
> +
> + s->iwin.cursor++;
> +
> + if (s->iwin.size >= IWIN_SIZE)
> + return 1;
> +
> + if (s->iwin.cursor > s->iwin.origin)
> + s->iwin.inodes[s->iwin.size++] = inode;
> + return 0;
> +}
> +
> +/*
> + * Travease the inode lists in order - newest first.
> + * And fill @s->iwin.inodes with inodes positioned in [@pos, @pos+IWIN_SIZE).
> + */
> +static int iwin_fill(struct session *s, unsigned long pos)
> +{
> + struct inode *inode;
> + struct super_block *sb;
> +
> + s->iwin.origin = pos;
> + s->iwin.cursor = 0;
> + s->iwin.size = 0;
> +
> + /*
> + * We have a cursor inode, clean and expected to be unchanged.
> + */
> + if (s->ipos.inode && pos >= s->ipos.pos &&
> + !(s->ipos.state & I_DIRTY) &&
> + s->ipos.state == s->ipos.inode->i_state) {
> + inode = s->ipos.inode;
> + s->iwin.cursor = s->ipos.pos;
> + goto continue_from_saved;
> + }
> +
> + if (s->ls_options & LS_OPT_CLEAN)
> + goto clean_inodes;
> +
> + spin_lock(&sb_lock);
> + list_for_each_entry(sb, &super_blocks, s_list) {
> + if (s->ls_dev && s->ls_dev != sb->s_dev)
> + continue;
> +
> + list_for_each_entry(inode, &sb->s_dirty, i_list) {
> + if (iwin_push(s, inode))
> + goto out_full_unlock;
> + }
> + list_for_each_entry(inode, &sb->s_io, i_list) {
> + if (iwin_push(s, inode))
> + goto out_full_unlock;
> + }
> + }
> + spin_unlock(&sb_lock);
> +
> +clean_inodes:
> + list_for_each_entry(inode, &inode_in_use, i_list) {
> + if (iwin_push(s, inode))
> + goto out_full;
> +continue_from_saved:
> + ;
> + }
> +
> + if (s->ls_options & LS_OPT_INUSE)
> + return 0;
> +
> + list_for_each_entry(inode, &inode_unused, i_list) {
> + if (iwin_push(s, inode))
> + goto out_full;
> + }
> +
> + return 0;
> +
> +out_full_unlock:
> + spin_unlock(&sb_lock);
> +out_full:
> + return 1;
> +}
> +
> +static struct inode *iwin_inode(struct session *s, unsigned long pos)
> +{
> + if ((iwin_full(s) && pos >= s->iwin.origin + s->iwin.size)
> + || pos < s->iwin.origin)
> + iwin_fill(s, pos);
> +
> + if (pos >= s->iwin.cursor)
> + return NULL;
> +
> + s->ipos.pos = pos;
> + s->ipos.inode = s->iwin.inodes[pos - s->iwin.origin];
> + BUG_ON(!s->ipos.inode);
> + return s->ipos.inode;
> +}
> +
> +static void show_inode(struct seq_file *m, struct inode *inode)
> +{
> + char state[] = "--"; /* dirty, locked */
> + struct dentry *dentry;
> + loff_t size = i_size_read(inode);
> + unsigned long nrpages;
> + int percent;
> + int refcnt;
> + int shift;
> +
> + if (!size)
> + size++;
> +
> + if (inode->i_mapping)
> + nrpages = inode->i_mapping->nrpages;
> + else {
> + nrpages = 0;
> + WARN_ON(1);
> + }
> +
> + for (shift = 0; (size >> shift) > ULONG_MAX / 128; shift += 12)
> + ;
> + percent = min(100UL, (((100 * nrpages) >> shift) << PAGE_CACHE_SHIFT) /
> + (unsigned long)(size >> shift));
> +
> + if (inode->i_state & (I_DIRTY_DATASYNC|I_DIRTY_PAGES))
> + state[0] = 'D';
> + else if (inode->i_state & I_DIRTY_SYNC)
> + state[0] = 'd';
> +
> + if (inode->i_state & I_LOCK)
> + state[0] = 'L';
> +
> + refcnt = 0;
> + list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
> + refcnt += atomic_read(&dentry->d_count);
> + }
> +
> + seq_printf(m, "%10lu %10llu %8lu %7d ",
> + inode->i_ino,
> + DIV_ROUND_UP(size, 1024),
> + nrpages << (PAGE_CACHE_SHIFT - 10),
> + percent);
> +
> + seq_printf(m, "%6d %5s %9lu ",
> + refcnt,
> + state,
> + (jiffies - inode->dirtied_when) / HZ);
> +
> +#ifdef CONFIG_PROC_FILECACHE_EXTRAS
> + seq_printf(m, "%8u %-16s",
> + inode->i_access_count,
> + inode->i_comm);
> +#endif
> +
> + seq_printf(m, "%02x:%02x(%s)\t",
> + MAJOR(inode->i_sb->s_dev),
> + MINOR(inode->i_sb->s_dev),
> + inode->i_sb->s_id);
> +
> + if (list_empty(&inode->i_dentry)) {
> + if (!atomic_read(&inode->i_count))
> + seq_puts(m, "(noname)\n");
> + else
> + seq_printf(m, "(%02x:%02x)\n",
> + imajor(inode), iminor(inode));
> + } else {
> + struct path path = {
> + .mnt = NULL,
> + .dentry = list_entry(inode->i_dentry.next,
> + struct dentry, d_alias)
> + };
> +
> + seq_path(m, &path, " \t\n\\");
> + seq_putc(m, '\n');
> + }
> +}
> +
> +static int ii_show(struct seq_file *m, void *v)
> +{
> + unsigned long index = *(loff_t *) v;
> + struct session *s = m->private;
> + struct inode *inode;
> +
> + if (index == 0) {
> + seq_puts(m, "# filecache " FILECACHE_VERSION "\n");
> + seq_puts(m, "# ino size cached cached% "
> + "refcnt state age "
> +#ifdef CONFIG_PROC_FILECACHE_EXTRAS
> + "accessed process "
> +#endif
> + "dev\t\tfile\n");
> + }
> +
> + inode = iwin_inode(s,index);
> + show_inode(m, inode);
> +
> + return 0;
> +}
> +
> +static void *ii_start(struct seq_file *m, loff_t *pos)
> +{
> + struct session *s = m->private;
> +
> + s->iwin.size = 0;
> + s->iwin.inodes = (struct inode **)
> + __get_free_pages( GFP_KERNEL, IWIN_PAGE_ORDER);
> + if (!s->iwin.inodes)
> + return NULL;
> +
> + spin_lock(&inode_lock);
> +
> + return iwin_inode(s, *pos) ? pos : NULL;
> +}
> +
> +static void *ii_next(struct seq_file *m, void *v, loff_t *pos)
> +{
> + struct session *s = m->private;
> +
> + (*pos)++;
> + return iwin_inode(s, *pos) ? pos : NULL;
> +}
> +
> +static void ii_stop(struct seq_file *m, void *v)
> +{
> + struct session *s = m->private;
> + struct inode *inode = s->ipos.inode;
> +
> + if (!s->iwin.inodes)
> + return;
> +
> + if (inode) {
> + __iget(inode);
> + s->ipos.state = inode->i_state;
> + }
> + spin_unlock(&inode_lock);
> +
> + free_pages((unsigned long) s->iwin.inodes, IWIN_PAGE_ORDER);
> + if (s->ipos.pinned_inode)
> + iput(s->ipos.pinned_inode);
> + s->ipos.pinned_inode = inode;
> +}
> +
> +/*
> + * Listing of cached page ranges of a file.
> + *
> + * Usage:
> + * echo 'file name' > /proc/filecache
> + * cat /proc/filecache
> + */
> +
> +unsigned long page_mask;
> +#define PG_MMAP PG_lru /* reuse any non-relevant flag */
> +#define PG_BUFFER PG_swapcache /* ditto */
> +#define PG_DIRTY PG_error /* ditto */
> +#define PG_WRITEBACK PG_buddy /* ditto */
> +
> +/*
> + * Page state names, prefixed by their abbreviations.
> + */
> +struct {
> + unsigned long mask;
> + const char *name;
> + int faked;
> +} page_flag [] = {
> + {1 << PG_referenced, "R:referenced", 0},
> + {1 << PG_active, "A:active", 0},
> + {1 << PG_MMAP, "M:mmap", 1},
> +
> + {1 << PG_uptodate, "U:uptodate", 0},
> + {1 << PG_dirty, "D:dirty", 0},
> + {1 << PG_writeback, "W:writeback", 0},
> + {1 << PG_reclaim, "X:readahead", 0},
> +
> + {1 << PG_private, "P:private", 0},
> + {1 << PG_owner_priv_1, "O:owner", 0},
> +
> + {1 << PG_BUFFER, "b:buffer", 1},
> + {1 << PG_DIRTY, "d:dirty", 1},
> + {1 << PG_WRITEBACK, "w:writeback", 1},
> +};
> +
> +static unsigned long page_flags(struct page* page)
> +{
> + unsigned long flags;
> + struct address_space *mapping = page_mapping(page);
> +
> + flags = page->flags & page_mask;
> +
> + if (page_mapped(page))
> + flags |= (1 << PG_MMAP);
> +
> + if (page_has_buffers(page))
> + flags |= (1 << PG_BUFFER);
> +
> + if (mapping) {
> + if (radix_tree_tag_get(&mapping->page_tree,
> + page_index(page),
> + PAGECACHE_TAG_WRITEBACK))
> + flags |= (1 << PG_WRITEBACK);
> +
> + if (radix_tree_tag_get(&mapping->page_tree,
> + page_index(page),
> + PAGECACHE_TAG_DIRTY))
> + flags |= (1 << PG_DIRTY);
> + }
> +
> + return flags;
> +}
> +
> +static int pages_similiar(struct page* page0, struct page* page)
> +{
> + if (page_count(page0) != page_count(page))
> + return 0;
> +
> + if (page_flags(page0) != page_flags(page))
> + return 0;
> +
> + return 1;
> +}
> +
> +static void show_range(struct seq_file *m, struct page* page, unsigned long len)
> +{
> + int i;
> + unsigned long flags;
> +
> + if (!m || !page)
> + return;
> +
> + seq_printf(m, "%lu\t%lu\t", page->index, len);
> +
> + flags = page_flags(page);
> + for (i = 0; i < ARRAY_SIZE(page_flag); i++)
> + seq_putc(m, (flags & page_flag[i].mask) ?
> + page_flag[i].name[0] : '_');
> +
> + seq_printf(m, "\t%d\n", page_count(page));
> +}
> +
> +#define BATCH_LINES 100
> +static pgoff_t show_file_cache(struct seq_file *m,
> + struct address_space *mapping, pgoff_t start)
> +{
> + int i;
> + int lines = 0;
> + pgoff_t len = 0;
> + struct pagevec pvec;
> + struct page *page;
> + struct page *page0 = NULL;
> +
> + for (;;) {
> + pagevec_init(&pvec, 0);
> + pvec.nr = radix_tree_gang_lookup(&mapping->page_tree,
> + (void **)pvec.pages, start + len, PAGEVEC_SIZE);
> +
> + if (pvec.nr == 0) {
> + show_range(m, page0, len);
> + start = ULONG_MAX;
> + goto out;
> + }
> +
> + if (!page0)
> + page0 = pvec.pages[0];
> +
> + for (i = 0; i < pvec.nr; i++) {
> + page = pvec.pages[i];
> +
> + if (page->index == start + len &&
> + pages_similiar(page0, page))
> + len++;
> + else {
> + show_range(m, page0, len);
> + page0 = page;
> + start = page->index;
> + len = 1;
> + if (++lines > BATCH_LINES)
> + goto out;
> + }
> + }
> + }
> +
> +out:
> + return start;
> +}
> +
> +static int pg_show(struct seq_file *m, void *v)
> +{
> + struct session *s = m->private;
> + struct file *file = s->query_file;
> + pgoff_t offset;
> +
> + if (!file)
> + return ii_show(m, v);
> +
> + offset = *(loff_t *) v;
> +
> + if (!offset) { /* print header */
> + int i;
> +
> + seq_puts(m, "# file ");
> + seq_path(m, &file->f_path, " \t\n\\");
> +
> + seq_puts(m, "\n# flags");
> + for (i = 0; i < ARRAY_SIZE(page_flag); i++)
> + seq_printf(m, " %s", page_flag[i].name);
> +
> + seq_puts(m, "\n# idx\tlen\tstate\t\trefcnt\n");
> + }
> +
> + s->start_offset = offset;
> + s->next_offset = show_file_cache(m, file->f_mapping, offset);
> +
> + return 0;
> +}
> +
> +static void *file_pos(struct file *file, loff_t *pos)
> +{
> + loff_t size = i_size_read(file->f_mapping->host);
> + pgoff_t end = DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
> + pgoff_t offset = *pos;
> +
> + return offset < end ? pos : NULL;
> +}
> +
> +static void *pg_start(struct seq_file *m, loff_t *pos)
> +{
> + struct session *s = m->private;
> + struct file *file = s->query_file;
> + pgoff_t offset = *pos;
> +
> + if (!file)
> + return ii_start(m, pos);
> +
> + rcu_read_lock();
> +
> + if (offset - s->start_offset == 1)
> + *pos = s->next_offset;
> + return file_pos(file, pos);
> +}
> +
> +static void *pg_next(struct seq_file *m, void *v, loff_t *pos)
> +{
> + struct session *s = m->private;
> + struct file *file = s->query_file;
> +
> + if (!file)
> + return ii_next(m, v, pos);
> +
> + *pos = s->next_offset;
> + return file_pos(file, pos);
> +}
> +
> +static void pg_stop(struct seq_file *m, void *v)
> +{
> + struct session *s = m->private;
> + struct file *file = s->query_file;
> +
> + if (!file)
> + return ii_stop(m, v);
> +
> + rcu_read_unlock();
> +}
> +
> +struct seq_operations seq_filecache_op = {
> + .start = pg_start,
> + .next = pg_next,
> + .stop = pg_stop,
> + .show = pg_show,
> +};
> +
> +/*
> + * Implement the manual drop-all-pagecache function
> + */
> +
> +#define MAX_INODES (PAGE_SIZE / sizeof(struct inode *))
> +static int drop_pagecache(void)
> +{
> + struct hlist_head *head;
> + struct hlist_node *node;
> + struct inode *inode;
> + struct inode **inodes;
> + unsigned long i, j, k;
> + int err = 0;
> +
> + inodes = (struct inode **)__get_free_pages(GFP_KERNEL, IWIN_PAGE_ORDER);
> + if (!inodes)
> + return -ENOMEM;
> +
> + for (i = 0; (head = get_inode_hash_budget(i)); i++) {
> + if (hlist_empty(head))
> + continue;
> +
> + j = 0;
> + cond_resched();
> +
> + /*
> + * Grab some inodes.
> + */
> + spin_lock(&inode_lock);
> + hlist_for_each (node, head) {
> + inode = hlist_entry(node, struct inode, i_hash);
> + if (!atomic_read(&inode->i_count))
> + continue;
> + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
> + continue;
> + if (!inode->i_mapping || !inode->i_mapping->nrpages)
> + continue;
> + __iget(inode);
> + inodes[j++] = inode;
> + if (j >= MAX_INODES)
> + break;
> + }
> + spin_unlock(&inode_lock);
> +
> + /*
> + * Free clean pages.
> + */
> + for (k = 0; k < j; k++) {
> + inode = inodes[k];
> + invalidate_mapping_pages(inode->i_mapping, 0, ~1);
> + iput(inode);
> + }
> +
> + /*
> + * Simply ignore the remaining inodes.
> + */
> + if (j >= MAX_INODES && !err) {
> + printk(KERN_WARNING
> + "Too many collides in inode hash table.\n"
> + "Pls boot with a larger ihash_entries=XXX.\n");
> + err = -EAGAIN;
> + }
> + }
> +
> + free_pages((unsigned long) inodes, IWIN_PAGE_ORDER);
> + return err;
> +}
> +
> +static void drop_slabcache(void)
> +{
> + int nr_objects;
> +
> + do {
> + nr_objects = shrink_slab(1000, GFP_KERNEL, 1000);
> + } while (nr_objects > 10);
> +}
> +
> +/*
> + * Proc file operations.
> + */
> +
> +static int filecache_open(struct inode *inode, struct file *proc_file)
> +{
> + struct seq_file *m;
> + struct session *s;
> + unsigned size;
> + char *buf = 0;
> + int ret;
> +
> + if (!try_module_get(THIS_MODULE))
> + return -ENOENT;
> +
> + s = session_create();
> + if (IS_ERR(s)) {
> + ret = PTR_ERR(s);
> + goto out;
> + }
> + set_session(proc_file, s);
> +
> + size = SBUF_SIZE;
> + buf = kmalloc(size, GFP_KERNEL);
> + if (!buf) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + ret = seq_open(proc_file, &seq_filecache_op);
> + if (!ret) {
> + m = proc_file->private_data;
> + m->private = s;
> + m->buf = buf;
> + m->size = size;
> + }
> +
> +out:
> + if (ret) {
> + kfree(s);
> + kfree(buf);
> + module_put(THIS_MODULE);
> + }
> + return ret;
> +}
> +
> +static int filecache_release(struct inode *inode, struct file *proc_file)
> +{
> + struct session *s = get_session(proc_file);
> + int ret;
> +
> + session_release(s);
> + ret = seq_release(inode, proc_file);
> + module_put(THIS_MODULE);
> + return ret;
> +}
> +
> +ssize_t filecache_write(struct file *proc_file, const char __user * buffer,
> + size_t count, loff_t *ppos)
> +{
> + struct session *s;
> + char *name;
> + int err = 0;
> +
> + if (count >= PATH_MAX + 5)
> + return -ENAMETOOLONG;
> +
> + name = kmalloc(count+1, GFP_KERNEL);
> + if (!name)
> + return -ENOMEM;
> +
> + if (copy_from_user(name, buffer, count)) {
> + err = -EFAULT;
> + goto out;
> + }
> +
> + /* strip the optional newline */
> + if (count && name[count-1] == '\n')
> + name[count-1] = '\0';
> + else
> + name[count] = '\0';
> +
> + s = get_session(proc_file);
> + if (!strcmp(name, "set private")) {
> + s->private_session = 1;
> + goto out;
> + }
> +
> + if (!strncmp(name, "cat ", 4)) {
> + err = session_update_file(s, name+4);
> + goto out;
> + }
> +
> + if (!strncmp(name, "ls", 2)) {
> + err = session_update_file(s, NULL);
> + if (!err)
> + err = ls_parse_options(name+2, s);
> + if (!err && !s->private_session) {
> + global_session.ls_dev = s->ls_dev;
> + global_session.ls_options = s->ls_options;
> + }
> + goto out;
> + }
> +
> + if (!strncmp(name, "drop pagecache", 14)) {
> + err = drop_pagecache();
> + goto out;
> + }
> +
> + if (!strncmp(name, "drop slabcache", 14)) {
> + drop_slabcache();
> + goto out;
> + }
> +
> + /* err = -EINVAL; */
> + err = session_update_file(s, name);
> +
> +out:
> + kfree(name);
> +
> + return err ? err : count;
> +}
> +
> +static struct file_operations proc_filecache_fops = {
> + .owner = THIS_MODULE,
> + .open = filecache_open,
> + .release = filecache_release,
> + .write = filecache_write,
> + .read = seq_read,
> + .llseek = seq_lseek,
> +};
> +
> +
> +static __init int filecache_init(void)
> +{
> + int i;
> + struct proc_dir_entry *entry;
> +
> + entry = create_proc_entry("filecache", 0600, NULL);
> + if (entry)
> + entry->proc_fops = &proc_filecache_fops;
> +
> + for (page_mask = i = 0; i < ARRAY_SIZE(page_flag); i++)
> + if (!page_flag[i].faked)
> + page_mask |= page_flag[i].mask;
> +
> + return 0;
> +}
> +
> +static void filecache_exit(void)
> +{
> + remove_proc_entry("filecache", NULL);
> + if (global_session.query_file)
> + fput(global_session.query_file);
> +}
> +
> +MODULE_AUTHOR("Fengguang Wu <wfg@...l.ustc.edu.cn>");
> +MODULE_LICENSE("GPL");
> +
> +module_init(filecache_init);
> +module_exit(filecache_exit);
> --- linux-2.6.orig/include/linux/fs.h
> +++ linux-2.6/include/linux/fs.h
> @@ -775,6 +775,11 @@ struct inode {
> void *i_security;
> #endif
> void *i_private; /* fs or device private pointer */
> +
> +#ifdef CONFIG_PROC_FILECACHE_EXTRAS
> + unsigned int i_access_count; /* opened how many times? */
> + char i_comm[16]; /* opened first by which app? */
> +#endif
> };
>
> /*
> @@ -860,6 +865,13 @@ static inline unsigned imajor(const stru
> return MAJOR(inode->i_rdev);
> }
>
> +static inline void inode_accessed(struct inode *inode)
> +{
> +#ifdef CONFIG_PROC_FILECACHE_EXTRAS
> + inode->i_access_count++;
> +#endif
> +}
> +
> extern struct block_device *I_BDEV(struct inode *inode);
>
> struct fown_struct {
> @@ -2171,6 +2183,7 @@ extern void remove_inode_hash(struct ino
> static inline void insert_inode_hash(struct inode *inode) {
> __insert_inode_hash(inode, inode->i_ino);
> }
> +struct hlist_head * get_inode_hash_budget(unsigned long index);
>
> extern struct file * get_empty_filp(void);
> extern void file_move(struct file *f, struct list_head *list);
> --- linux-2.6.orig/fs/open.c
> +++ linux-2.6/fs/open.c
> @@ -842,6 +842,7 @@ static struct file *__dentry_open(struct
> goto cleanup_all;
> }
>
> + inode_accessed(inode);
> f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
>
> file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
> --- linux-2.6.orig/fs/Kconfig
> +++ linux-2.6/fs/Kconfig
> @@ -265,4 +265,34 @@ endif
> source "fs/nls/Kconfig"
> source "fs/dlm/Kconfig"
>
> +config PROC_FILECACHE
> + tristate "/proc/filecache support"
> + default m
> + depends on PROC_FS
> + help
> + This option creates a file /proc/filecache which enables one to
> + query/drop the cached files in memory.
> +
> + A quick start guide:
> +
> + # echo 'ls' > /proc/filecache
> + # head /proc/filecache
> +
> + # echo 'cat /bin/bash' > /proc/filecache
> + # head /proc/filecache
> +
> + # echo 'drop pagecache' > /proc/filecache
> + # echo 'drop slabcache' > /proc/filecache
> +
> + For more details, please check Documentation/filesystems/proc.txt .
> +
> + It can be a handy tool for sysadms and desktop users.
> +
> +config PROC_FILECACHE_EXTRAS
> + bool "track extra states"
> + default y
> + depends on PROC_FILECACHE
> + help
> + Track extra states that costs a little more time/space.
> +
> endmenu
> --- linux-2.6.orig/fs/proc/Makefile
> +++ linux-2.6/fs/proc/Makefile
> @@ -2,7 +2,8 @@
> # Makefile for the Linux proc filesystem routines.
> #
>
> -obj-$(CONFIG_PROC_FS) += proc.o
> +obj-$(CONFIG_PROC_FS) += proc.o
> +obj-$(CONFIG_PROC_FILECACHE) += filecache.o
>
> proc-y := nommu.o task_nommu.o
> proc-$(CONFIG_MMU) := mmu.o task_mmu.o
--
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