From: ebiederm@xmission.com (Eric W. Biederman)
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/23] proc cleanup.
Date: Sat, 25 Feb 2006 08:20:32 -0700 [thread overview]
Message-ID: <m13bi731of.fsf@ebiederm.dsl.xmission.com> (raw)
In-Reply-To: <20060225042757.1442ee2c.akpm@osdl.org> (Andrew Morton's message of "Sat, 25 Feb 2006 04:27:57 -0800")
Andrew Morton <akpm@osdl.org> writes:
> ebiederm@xmission.com (Eric W. Biederman) wrote:
>>
>> When working on pid namespaces I keep tripping over /proc.
>> It's hard coded inode numbers and the amount of cruft
>> accumulated over the years makes it hard to deal with.
>>
>> So to put /proc out of my misery here is a series of patches that
>> removes the worst of the warts.
>
> An additional 2.7k of vmlinux. A shame.
Looks like that at least is compiler dependent, with gcc-3.3.5 I get:
text data bss dec hex filename
2601428 502342 226092 3329862 32cf46 ../linux-2.6-ns-mirror-build1/vmlinux
2602548 502494 226092 3331134 32d43e ../linux-2.6-ns-mirror-build2/vmlinux
So it looks like 1K of test and about 100 bytes of data.
Investigating this quickly. Because of the refactoring it
is hard to pin this down to any major culprit. But that is
also good news in that it doesn't look like an inline function
is responsible for this growth :)
It looks like the culprit for small amounts of growth is
the work to see if a task still exists, and other similar
checks that were needed but missing.
For the big chunks it looks like the work to populate the
dcache during readdir, which keeps the inode numbers in
sync and should help readdir+stat performance.
The other big culprit is proc_flush_task which is both
more comprehensive and simpler that proc_pid_flush+proc_pid_unhash=107+28.
But unfortunately that has made it a lot bigger.
So short of getting better dcache helpers for the case
where readdir populates the dcache it doesn't look the code
size will come down much.
The one practical thing that will help a little is that it
looks like with just a little more work we can replace
all of read_lock(&tasklist_lock) with rcu_read_lock().
add/remove: 33/23 grow/shrink: 28/16 up/down: 4968/-3619 (1349)
function old new delta
proc_flush_task - 605 +605
proc_check_dentry_visible - 325 +325
proc_fill_cache - 256 +256
proc_fd_instantiate - 243 +243
tref_get_by_task - 200 +200
first_tid - 179 +179
tgid_base_stuff 336 504 +168
tid_base_stuff 320 480 +160
first_tgid - 159 +159
proc_pident_instantiate - 158 +158
proc_task_instantiate - 128 +128
proc_pid_instantiate - 128 +128
attr_dir_stuff - 120 +120
proc_attr_dir_operations - 108 +108
tref_get_by_pid - 107 +107
proc_task_getattr - 105 +105
next_tid - 100 +100
next_tgid - 89 +89
tref_put - 87 +87
proc_attr_dir_inode_operations - 84 +84
do_maps_open - 80 +80
proc_fd_fill_cache - 63 +63
proc_task_fill_cache - 60 +60
proc_pid_fill_cache - 60 +60
__detach_pid 136 195 +59
proc_info_read 111 164 +53
oom_adjust_read 162 215 +53
proc_get_sb 26 78 +52
seccomp_write 168 218 +50
seccomp_read 164 214 +50
oom_adjust_write 164 214 +50
proc_pid_attr_read 124 172 +48
proc_base_stuff - 48 +48
proc_pid_attr_write 148 194 +46
proc_fd_link 122 168 +46
proc_exe_link 152 198 +46
mounts_open 157 200 +43
proc_root_link 99 141 +42
proc_cwd_link 99 141 +42
tid_fd_revalidate 207 247 +40
proc_pident_fill_cache - 40 +40
get_tref_task - 33 +33
dup_task_struct 137 170 +33
m_stop 59 88 +29
m_start 235 264 +29
tref_reset - 28 +28
proc_attr_dir_readdir - 28 +28
proc_pident_readdir 270 296 +26
proc_attr_dir_lookup - 22 +22
tref_set - 21 +21
tref_fini - 21 +21
tref_init - 18 +18
proc_pid_follow_link 98 116 +18
init_tref - 16 +16
init_task 1328 1344 +16
pid_revalidate 178 192 +14
attach_pid 149 162 +13
tref_get - 8 +8
mem_read 430 438 +8
proc_alloc_inode 98 102 +4
proc_task_readdir 320 323 +3
pid_delete_dentry 24 21 -3
m_next 70 61 -9
proc_readfd 327 307 -20
copy_process 3190 3170 -20
smaps_open 43 22 -21
maps_open 43 22 -21
proc_tid_attr_lookup 22 - -22
proc_tgid_attr_lookup 22 - -22
proc_delete_inode 129 105 -24
pid_base_dentry_operations 24 - -24
proc_tid_attr_readdir 28 - -28
proc_tgid_attr_readdir 28 - -28
proc_pid_flush 28 - -28
release_task 257 228 -29
proc_permission 38 - -38
proc_pid_make_inode 205 166 -39
unhash_process 73 33 -40
de_thread 1310 1266 -44
proc_check_root 55 - -55
proc_task_lookup 244 188 -56
pid_base_iput 62 - -62
proc_pid_readdir 303 229 -74
tid_attr_stuff 80 - -80
tgid_attr_stuff 80 - -80
proc_task_permission 82 - -82
proc_tid_attr_inode_operations 84 - -84
proc_tgid_attr_inode_operations 84 - -84
proc_mem_inode_operations 84 - -84
get_tid_list 97 - -97
proc_pid_unhash 107 - -107
proc_tid_attr_operations 108 - -108
proc_tgid_attr_operations 108 - -108
proc_lookupfd 240 99 -141
get_tgid_list 146 - -146
proc_task_root_link 218 - -218
proc_check_chroot 245 - -245
switch_exec_pids 290 - -290
proc_pid_lookup 503 145 -358
proc_pident_lookup 742 142 -600
Eric
next prev parent reply other threads:[~2006-02-25 15:21 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-23 15:52 [PATCH 00/23] proc cleanup Eric W. Biederman
2006-02-23 15:54 ` [PATCH 01/23] tref: Implement task references Eric W. Biederman
2006-02-23 15:56 ` [PATCH 02/23] proc: Fix the .. inode number on /proc/<pid>/fd Eric W. Biederman
2006-02-23 15:57 ` [PATCH 03/23] proc: Remove useless BKL in proc_pid_readlink Eric W. Biederman
2006-02-23 15:58 ` [PATCH 04/23] proc: Remove unnecessary and misleading assignments from proc_pid_make_inode Eric W. Biederman
2006-02-23 16:00 ` [PATCH 05/23] proc: Simplify the ownership rules for /proc Eric W. Biederman
2006-02-23 16:02 ` Eric W. Biederman
2006-02-23 16:04 ` [PATCH 06/23] proc: Replace proc_inode.type with proc_inode.fd Eric W. Biederman
2006-02-23 16:05 ` [PATCH 07/23] proc: Remove bogus proc_task_permission Eric W. Biederman
2006-02-23 16:06 ` [PATCH 08/23] proc: Kill proc_mem_inode_operations Eric W. Biederman
2006-02-23 16:08 ` [PATCH 09/23] proc: Properly filter out files that are not visible to a process Eric W. Biederman
2006-02-23 16:10 ` [PATCH 10/23] proc: Fix the link count for /proc/<pid>/task Eric W. Biederman
2006-02-23 16:12 ` [PATCH 11/23] proc: Move proc_maps_operations into task_mmu.c Eric W. Biederman
2006-02-23 16:15 ` [PATCH 12/23] proc: Rewrite the proc dentry flush on exit optimization Eric W. Biederman
2006-02-23 16:16 ` [PATCH 13/23] proc: Close the race of a process dying durning lookup Eric W. Biederman
2006-02-23 16:18 ` [PATCH 14/23] proc: Make PROC_NUMBUF the buffer size for holding a integers as strings Eric W. Biederman
2006-02-23 16:20 ` [PATCH 15/23] proc: refactor reading directories of tasks Eric W. Biederman
2006-02-23 16:23 ` [PATCH 16/23] proc: Don't lock task_structs indefinitely Eric W. Biederman
2006-02-23 16:24 ` [PATCH 17/23] proc: Give the root directory a task Eric W. Biederman
2006-02-23 16:25 ` [PATCH 18/23] proc: Reorder the functions in base.c Eric W. Biederman
2006-02-23 16:27 ` [PATCH 19/23] proc: Modify proc_pident_lookup to be completely table driven Eric W. Biederman
2006-02-23 16:28 ` [PATCH 20/23] proc: Make the generation of the self symlink " Eric W. Biederman
2006-02-23 16:30 ` [PATCH 21/23] proc: Factor out an instantiate method from every lookup method Eric W. Biederman
2006-02-23 16:32 ` [PATCH 22/23] proc: Remove the hard coded inode numbers Eric W. Biederman
2006-02-23 16:34 ` [PATCH 23/23] proc: Merge proc_tid_attr and proc_tgid_attr Eric W. Biederman
2006-02-23 16:49 ` [PATCH 01/23] tref: Implement task references Eric W. Biederman
2006-03-02 19:16 ` Oleg Nesterov
2006-03-02 20:37 ` Oleg Nesterov
2006-03-02 22:19 ` Eric W. Biederman
2006-03-03 16:56 ` Oleg Nesterov
2006-03-03 17:48 ` Eric W. Biederman
2006-03-04 11:16 ` Eric W. Biederman
2006-03-04 12:31 ` Oleg Nesterov
2006-03-04 17:30 ` Oleg Nesterov
2006-03-06 21:06 ` Oleg Nesterov
2006-03-06 22:18 ` Eric W. Biederman
2006-03-07 20:44 ` Oleg Nesterov
2006-03-07 1:39 ` Eric W. Biederman
2006-03-07 20:38 ` Oleg Nesterov
2006-03-07 13:12 ` Eric W. Biederman
2006-03-07 21:02 ` Oleg Nesterov
2006-03-07 23:00 ` Eric W. Biederman
2006-03-03 19:23 ` Oleg Nesterov
2006-03-04 10:51 ` Eric W. Biederman
2006-02-25 12:27 ` [PATCH 00/23] proc cleanup Andrew Morton
2006-02-25 13:34 ` Eric W. Biederman
2006-02-25 15:20 ` Eric W. Biederman [this message]
2006-02-27 15:26 ` Serge E. Hallyn
2006-02-27 15:56 ` Eric W. Biederman
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