Wmat: Fixing broken links

2010-01-28T00:17:08Z

Fixing broken links

Wmat: /* Program for producing report (Download) */

2010-01-28T00:11:55Z

‎Program for producing report (Download)

Chris at 12:44, 14 July 2007

2007-07-14T12:44:21Z

Wmat: Legacy Content Conversion

2006-12-14T20:32:44Z

Legacy Content Conversion

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Here are some miscellaneous notes on using Linux tiny. I wrote this up really quickly while I was
integrating Linux-tiny into a 2.6.11 kernel and doing some size testing.

I'm providing these raw notes so that others might benefit from my experience.

== Patch Notes ==
Here are some notes on individual linux-tiny sub-patches:

== devlist.patch ==
* replaces device allocation code, don't know size impact, is NOT conditional
** maybe should add, but don't know - looks dangerous

== core-small.patch - CONFIG_CORE_SMALL ==
Add CONFIG_CORE_SMALL Kconfig option

=== CONFIG_CORE_SMALL patches ===
These are hash table and data structure static size adjustments
* pid-max.patch
* user-hash.patch
* futex-queues.patch
* tvec_bases.patch
* con_buf.patch

== config-net-small.patch ==
Add CONFIG_NET_SMALL Kconfig option

=== CONFIG_NET_SMALL patches ===
These tune some net-related data sizes
* cache_defer_hash.patch
* unix_socket_table.patch
* inet_protos.patch
* flow-cache-small.patch

== Miscellanoues patches ==
* small-8023.patch - what does this do?
* tg3-oops.patch - what does this do?

== *inline patches ==
* just make big routines not inline (unconditionally)
** Seems pretty safe to me.

== 06-crypto-sleep.patch ==
* looks scary - not immediately obvious from patch how it saves size.

== # measurement bits ==
Looks like very harmless stuff to instrument kernel for mem debugging, and
give tools for parsing stuff.

* kmalloc-accounting.patch - keep track of kmallocs
* audit-bootmem - print out all bootmem allocations
* bloat-o-meter.patch - provides bloat-o-meter program to compare two kernel binary images
**This script shows the size difference on a symbol-by-symbol basis between two binaries (sorted by the amount of difference)

* deprecate-inline.patch - mark inlines as deprecated so compiler emits warnings
**Note that it provides count-inlines program to parse compiler output and report size of inlines.
* func-size.patch - use information about inlines to calculate function sizes (script is very similar to count-inlines program)

== kill-printk.patch ==
* is single biggest reducer of kernel size, doesn't seem to work with serial console!!
** CONFIG_PRINTK

== nobug.patch ==
Allow elimination of BUG code, which expands with file and line strings.
There are 1776 BUG() references in the 2.6.11 kernel. There are 1930 BUG_ON(xxx) references in the kernel.
* uses CONFIG_BUG

== nopanic.patch ==
too dangerous to turn off panic, not used.

== no-elf-core.patch ==
Allow disabling of ELF core dumps
* CONFIG_ELF_CORE

== no-kcore.patch ==
Allow disabling of /proc/kcore, is x86-specific
* uses CONFIG_PROC_KCORE

== no-aio.patch ==
Allow disabling of Posix async IO
* uses CONFIG_AIO

== no-xattr.patch ==
Allow disabling of xattr syscalls
* uses CONFIG_XATTR

== fslock.patch ==
Allow disabling of file locking syscalls
* uses CONFIG_FILE_LOCKING

== direct-io-core.patch ==
Allow disabling of direct IO support
* uses CONFIG_DIRECTIO

== Changes in number of in-kernel items ==
=== max-swapfiles.patch ===
Make number of swapfiles configurable (default=32) (shift=5 => 32 files, shift=0 => 1 file)
* uses CONFIG_MAX_SWAPFILES_SHIFT

=== ldiscs.patch ===
Make number of tty line disciplines configurable (default=16)
* uses CONFIG_NR_LDISCS

=== max_user_rt_prio.patch ===
Make number of schedule slots configurable (default=100)
* uses CONFIG_MAX_USER_RT_PRIO

== change-hz.patch ==
It's not obvious how this changes the size of the kernel, and it appears to be x86 only

= Notes on building and size reductions from various configs =
Notes on OSK builds:
* first, did 'quilt pop pm/deferred-resume-test.patch', then built to get vmlinux.baseline
<pre> text data bss dec filename
2107356 333344 113680 2554380 vmlinux.baseline
</pre>

* did 'quilt push -a', then built to get vmlinux.patched
<pre> bloat-o-meter vmlinux.baseline vmlinux.patched = +2920/-8884
text data bss dec filename
2101372 333888 113648 2548908 vmlinux.patched
</pre>

* configured all parameters at minimums, then built
** couldn't finish linking, and got the following errors:
*** undefined reference to add_preferred_console
*** undefined reference to generic_setxattr and generic_getxattr
*** undefined reference to printk
* configured printk and xattrs back on, then built to get vmlinux.try1

<pre> bloat-o-meter vmlinux.patches vmlinux.try1 = +4520/-350490
text data bss dec filename
1734504 90616 89036 1914156 vmlinux.try1
</pre>

Panic trying to mount rootfs via nfs
* tried to isolate nfs problem:
** configured with AIO, file locks and direct IO on - same problem
** configured with 5 swap files, 8 tty line disciplines, and 100 mat rt levels - same problem
** went back to working config - diffed and noticed NFS_FS was off
*** NFS_FS requires FILE_LOCKING

== Table of Config options ==
Here is a table showing default value and value recommended for size savings.

Note that I couldn't use CONFIG_PRINTK, CONFIG_XATTR or CONFIG_FILE_LOCKING in my setup.

{| border="1" cellpadding="5" cellspacing="0" align="center"
! style="background:#ffcc00;"|'''CONFIG option'''
! style="background:#ffcc00;"|'''description'''
! style="background:#ffcc00;"|'''default'''
! style="background:#ffcc00;"|'''small'''
|-
|CONFIG_CORE_SMALL ||tune some kernel data sizes ||N ||Y
|-
|CONFIG_NET_SMALL ||tune some net-related data sizes ||N ||Y
|-
|CONFIG_KMALLOC_ACCOUNTING||turn on kmalloc accounting ||N ||Y - for measurement
|-
|CONFIG_AUDIT_BOOTMEM ||print out all bootmem allocations ||N ||Y - for measurement
|-
|CONFIG_DEPRECATE_INLINES||cause compiler to emit info about inlines ||N ||Y - for measurement
|-
|CONFIG_PRINTK ||allow disable of printk code and message data ||Y ||N
|-
|CONFIG_BUG ||allow elimination of BUG (and BUG_ON??) code ||Y ||N
|-
|CONFIG_ELF_CORE ||allow disabling of ELF core dumps ||Y ||N
|-
|CONFIG_PROC_KCORE ||allow disabling of /proc/kcore ||Y ||N
|-
|CONFIG_AIO ||allow disabling of async IO syscalls ||Y ||N
|-
|CONFIG_XATTR ||allow disabling of xattr syscalls ||Y ||N
|-
|CONFIG_FILE_LOCKING ||allow disabling of file locking syscalls ||Y ||N
|-
|CONFIG_DIRECTIO ||allow disabling of direct IO support ||Y ||N
|-
|CONFIG_MAX_SWAPFILES_SHIFT||number of swapfiles ||5 ||0
|-
|CONFIG_NR_LDISCS ||number of tty line disciplines ||16 ||2?
|-
|CONFIG_MAX_USER_RT_PRIO||number of RT priority levels (schedule slots)||100 ||5?
|-
|style="background:#ffcc00;"|Other config options ||These are not in Linux-tiny, but help with size||default||small
|-
|CONFIG_KALLSYMS ||load all symbols for debugging/kksymoops ||Y ||N
|-
|CONFIG_SHMEM ||allow use of shmem filesystem ||Y ||N
|}

== Some results ==

This was for a quick check of Linux-tiny on an OSK board.

{| border="1" cellpadding="5" cellspacing="0" align="center"
! style="background:#ffcc00;"|'''section'''
! style="background:#ffcc00;"|'''vmlinux.baseline'''
! style="background:#ffcc00;"|'''vmlinux.try3'''
! style="background:#ffcc00;"|'''delta'''
! style="background:#ffcc00;"|'''percent'''
|-
|| text|| 2107356|| 2057276|| -50080||-2%
|-
|| data|| 333344|| 100988|| -232356||-69%
|-
|| bss|| 113680|| 92784|| -20896||-18%
|-
|total|| 2554380|| 2251048|| -303332||-11%
|}

== Program for producing report (Download) ==
*[[Image:size-delta|size delta]]

== Miscellaneous test notes ==
* kernel would not link with CONFIG_PRINTK=n
** undefined reference to add_preferred_console
** undefined reference to printk
* kernel would not link with CONFIG_XATTR=n
** undefined reference to generic_setxattr and generic_getxattr
* kernel would not mount root fs (NFS) with CONFIG_FILE_LOCKING=n

== Config changes ==
<pre>
[tbird@crest osk]$ diff config.baseline config.try3
--- config.baseline 2005-05-23 17:31:57.000000000 -0700
+++ config.try3 2005-05-23 17:31:40.000000000 -0700
@@ -1,7 +1,7 @@
#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.11.10-alp
-# Mon May 23 16:49:43 2005
+# Mon May 23 17:27:14 2005
#
CONFIG_ARM=y
CONFIG_MMU=y
@@ -34,34 +34,33 @@
CONFIG_FASTBOOT=y
# CONFIG_RTC_NO_SYNC is not set
CONFIG_PRESET_LPJ=0
-# CONFIG_EMBEDDED is not set
-CONFIG_KALLSYMS=y
-CONFIG_KALLSYMS_ALL=y
-CONFIG_KALLSYMS_EXTRA_PASS=y
+CONFIG_EMBEDDED=y
+# CONFIG_KALLSYMS is not set
# CONFIG_KMALLOC_ACCOUNTING is not set
# CONFIG_AUDIT_BOOTMEM is not set
CONFIG_PRINTK=y
-CONFIG_ELF_CORE=y
-# CONFIG_CORE_SMALL is not set
-# CONFIG_NET_SMALL is not set
-CONFIG_FUTEX=y
-CONFIG_EPOLL=y
-CONFIG_AIO=y
+# CONFIG_ELF_CORE is not set
+CONFIG_CORE_SMALL=y
+CONFIG_NET_SMALL=y
+# CONFIG_FUTEX is not set
+# CONFIG_EPOLL is not set
+# CONFIG_AIO is not set
CONFIG_XATTR=y
CONFIG_FILE_LOCKING=y
-CONFIG_DIRECTIO=y
+# CONFIG_DIRECTIO is not set
+# CONFIG_UID16 is not set
# CONFIG_MEASURE_INLINES is not set
CONFIG_CC_OPTIMIZE_FOR_SIZE=y
-CONFIG_SHMEM=y
+# CONFIG_SHMEM is not set
CONFIG_CC_ALIGN_FUNCTIONS=0
CONFIG_CC_ALIGN_LABELS=0
CONFIG_CC_ALIGN_LOOPS=0
CONFIG_CC_ALIGN_JUMPS=0
# CONFIG_TINY_CFLAGS is not set
-CONFIG_MAX_SWAPFILES_SHIFT=5
-CONFIG_NR_LDISCS=16
-CONFIG_MAX_USER_RT_PRIO=100
-# CONFIG_TINY_SHMEM is not set
+CONFIG_MAX_SWAPFILES_SHIFT=0
+CONFIG_NR_LDISCS=2
+CONFIG_MAX_USER_RT_PRIO=5
+CONFIG_TINY_SHMEM=y

#
# Loadable module support
@@ -435,6 +434,7 @@
CONFIG_SERIO=y
CONFIG_SERIO_SERPORT=y
# CONFIG_SERIO_CT82C710 is not set
+# CONFIG_SERIO_LIBPS2 is not set
# CONFIG_SERIO_RAW is not set

#
@@ -912,7 +912,7 @@
# CONFIG_DEBUG_SPINLOCK is not set
# CONFIG_DEBUG_KOBJECT is not set
CONFIG_BUG=y
-CONFIG_DEBUG_BUGVERBOSE=y
+# CONFIG_DEBUG_BUGVERBOSE is not set
CONFIG_DEBUG_INFO=y
# CONFIG_DEBUG_FS is not set
CONFIG_FRAME_POINTER=y
</pre>

== Series file ==
Please note that I didn't try all the patches. I only integrated and used 37 of the broken-out patches. You can see this from the series file I used, which follows:

<pre>
####################################
# start of linux tiny patches
# key:
# ## = patches Tim commented out
# # = patches commented out in original 2.6.11-tiny broken out series file

##tiny/tiny-extraversion.patch
#
# stuff already in -mm
#
##tiny/kgdb-ga.patch
##tiny/kgdboe-netpoll.patch
tiny/use-funit-at-a-time.patch
##tiny/devlist.patch
#
# tiny stuff
#
# core
tiny/core-small.patch
tiny/pid-max.patch
tiny/user-hash.patch
tiny/futex-queues.patch
tiny/tvec_bases.patch
tiny/con_buf.patch
# net
tiny/config-net-small.patch
tiny/cache_defer_hash.patch
tiny/unix_socket_table.patch
tiny/inet_protos.patch
tiny/flow-cache-small.patch
#
# Unconditional bits
#
##tiny/small-8023.patch
##tiny/tg3-oops.patch
tiny/namei-inlines.patch
tiny/buffer-inlines.patch
tiny/fs_open-inlines.patch
tiny/inode-inlines.patch
tiny/ext2namei-inlines.patch
tiny/fslocks-inline.patch
##tiny/06-crypto-sleep.patch
#
# build options
#
tiny/tiny-cflags.patch
#
# measurement bits
#
tiny/kmalloc-accounting.patch
tiny/audit-bootmem.patch
tiny/bloat-o-meter.patch
tiny/deprecate-inline.patch
tiny/func-size.patch
#
# trimmed debugging support
#
##tiny/no-doublefault.patch
tiny/kill-printk.patch
##tiny/tiny-panic.patch
tiny/nobug.patch
##tiny/nopanic.patch
tiny/no-elf-core.patch
tiny/no-kcore.patch
#
# trimmed code
#
# TRB - 5/19 - haven't looked at these yet
##tiny/tiny-crc.patch
##tiny/threadinfo-ool.patch
##tiny/semaphore-inline.patch
##tiny/slob.patch
##tiny/slob-accounting.patch
##tiny/mempool-shrink.patch
#tiny/sysfs-backingstore.patch
##tiny/no-translations.patch
#tiny/tinyvt.patch
#
# trimmed apis
#
# TRB - 5/19 - haven't looked at ## ones yet
##tiny/ptrace.patch
##tiny/remove-vm86.patch
##tiny/sysenter.patch
tiny/no-aio.patch
tiny/no-xattr.patch
tiny/fslock.patch
tiny/direct-io-core.patch
tiny/uid16.patch
#tiny/posix-timers.patch
##tiny/ethtool.patch
##tiny/inetpeer.patch
##tiny/net-filter.patch
##tiny/dev_mcast.patch
#tiny/rtnetlink.patch
##tiny/igmp.patch
##tiny/binfmt-script.patch
##tiny/elf-no-aout.patch
#
# trimmed constants
#
tiny/max-swapfiles.patch
tiny/ldiscs.patch
tiny/max_user_rt_prio.patch
##tiny/change-hz.patch
#
# trimmed hw support
#
# TRB - 5/19 - haven't looked at ## ones yet
#tiny/small-nomodedb.patch
##tiny/ide-hwif.patch
##tiny/sbf.patch
##tiny/serial-pci.patch
##tiny/dmi_blacklist.patch
##tiny/pci-quirks.patch
##tiny/tsc.patch
##tiny/cpu-support.patch
##tiny/mtrr.patch
#
# inflate cleanups
#
# TRB - 5/19 - haven't looked at ## ones yet
##tiny/inflate-noinline.patch
##tiny/inflate-formatting.patch
##tiny/inflate-legacy.patch
##tiny/inflate-input.patch
##tiny/inflate-iostate.patch
##tiny/inflate-huft.patch
##tiny/inflate-crc.patch
##tiny/inflate-killglobals.patch
##tiny/inflate-initramfs.patch
##tiny/inflate-initrd.patch
##tiny/inflate-i386.patch
##tiny/inflate-arm.patch
##tiny/inflate-x86_64.patch
#
# unsorted
#
# TRB - 5/19 - haven't looked at ## ones yet
##tiny/inflate-roll-crc.patch
##tiny/netpoll-timeout.patch
##tiny/movsl-mask.patch
#tiny/rolled-md4.patch
#tiny/kill-ext3-md4.patch

# end of linux tiny patches
####################################
</pre>

@@ Line 212: / Line 212: @@
-== Program for producing report (Download) ==
+== Program for producing report  ==
-*[[Media:size-delta|size delta]]
+<pre>
 == Miscellaneous test notes ==

← Older revision		Revision as of 12:44, 14 July 2007
Line 458:		Line 458:
	####################################		####################################
	</pre>		</pre>
		+
		+	[[Category: Linux Tiny]]

Linux Tiny Notes - Revision history

Wmat: Fixing broken links

Wmat: /* Program for producing report (Download) */

Chris at 12:44, 14 July 2007

Wmat: Legacy Content Conversion