Hi,
if I copy a compiled kernel tree to another location and run
make again in the new directory, a few files always get rebuilt.
These files only are rebuilt if the tree is a copy of another
tree and they are rebuilt only once.
Any ideas why this is the case?
arch=x86_64, make=3.80, filesystem=reiserfs
Log follows:
compiler@switch:/storage> cd linux-2.6.16/
compiler@switch:/storage/linux-2.6.16> make
CHK include/linux/version.h
CHK include/linux/compile.h
CHK usr/initramfs_list
Kernel: arch/x86_64/boot/bzImage is ready (#1)
Building modules, stage 2.
MODPOST
compiler@switch:/storage/linux-2.6.16> cd ..
compiler@switch:/storage> cp -ar linux-2.6.16/ linux-2.6.16-unmodified
compiler@switch:/storage> cd linux-2.6.16-unmodified/
compiler@switch:/storage/linux-2.6.16-unmodified> make
CHK include/linux/version.h
CHK include/linux/compile.h
CHK usr/initramfs_list
OUI2C drivers/ieee1394/oui.c
CC [M] drivers/ieee1394/oui.o
LD [M] drivers/ieee1394/ieee1394.o
UNROLL drivers/md/raid6int1.c
CC [M] drivers/md/raid6int1.o
UNROLL drivers/md/raid6int2.c
CC [M] drivers/md/raid6int2.o
UNROLL drivers/md/raid6int4.c
CC [M] drivers/md/raid6int4.o
UNROLL drivers/md/raid6int8.c
CC [M] drivers/md/raid6int8.o
UNROLL drivers/md/raid6int16.c
CC [M] drivers/md/raid6int16.o
UNROLL drivers/md/raid6int32.c
CC [M] drivers/md/raid6int32.o
UNROLL drivers/md/raid6altivec1.c
CC [M] drivers/md/raid6altivec1.o
UNROLL drivers/md/raid6altivec2.c
CC [M] drivers/md/raid6altivec2.o
UNROLL drivers/md/raid6altivec4.c
CC [M] drivers/md/raid6altivec4.o
UNROLL drivers/md/raid6altivec8.c
CC [M] drivers/md/raid6altivec8.o
LD [M] drivers/md/raid6.o
LD [M] drivers/md/dm-mod.o
LD [M] drivers/md/dm-multipath.o
LD [M] drivers/md/dm-snapshot.o
LD [M] drivers/md/dm-mirror.o
CC [M] drivers/media/video/videodev.o
CC [M] drivers/media/video/v4l2-common.o
CC [M] drivers/media/video/v4l1-compat.o
CC [M] drivers/media/video/compat_ioctl32.o
CC [M] drivers/media/video/bttv-driver.o
CC [M] drivers/media/video/bttv-cards.o
CC [M] drivers/media/video/bttv-if.o
CC [M] drivers/media/video/bttv-risc.o
CC [M] drivers/media/video/bttv-vbi.o
CC [M] drivers/media/video/bttv-i2c.o
CC [M] drivers/media/video/bttv-gpio.o
CC [M] drivers/media/video/bttv-input.o
CC [M] drivers/media/video/msp3400-driver.o
CC [M] drivers/media/video/msp3400-kthreads.o
CC [M] drivers/media/video/tuner-core.o
CC [M] drivers/media/video/tuner-types.o
CC [M] drivers/media/video/tuner-simple.o
CC [M] drivers/media/video/mt20xx.o
CC [M] drivers/media/video/tda8290.o
CC [M] drivers/media/video/tea5767.o
CC [M] drivers/media/video/zoran_procfs.o
CC [M] drivers/media/video/zoran_device.o
drivers/media/video/zoran_device.c: In function `zr36057_overlay':
drivers/media/video/zoran_device.c:539: warning: cast from pointer to integer of different size
CC [M] drivers/media/video/zoran_driver.o
CC [M] drivers/media/video/zoran_card.o
LD [M] drivers/media/video/bttv.o
LD [M] drivers/media/video/msp3400.o
CC [M] drivers/media/video/tvaudio.o
CC [M] drivers/media/video/tda7432.o
CC [M] drivers/media/video/tda9875.o
CC [M] drivers/media/video/ir-kbd-i2c.o
CC [M] drivers/media/video/tvmixer.o
CC [M] drivers/media/video/saa6588.o
CC [M] drivers/media/video/saa5246a.o
CC [M] drivers/media/video/saa5249.o
CC [M] drivers/media/video/c-qcam.o
CC [M] drivers/media/video/bw-qcam.o
CC [M] drivers/media/video/w9966.o
CC [M] drivers/media/video/saa7111.o
CC [M] drivers/media/video/saa7185.o
CC [M] drivers/media/video/zr36060.o
CC [M] drivers/media/video/saa7110.o
CC [M] drivers/media/video/adv7175.o
CC [M] drivers/media/video/vpx3220.o
CC [M] drivers/media/video/zr36050.o
CC [M] drivers/media/video/zr36016.o
CC [M] drivers/media/video/bt819.o
CC [M] drivers/media/video/bt856.o
CC [M] drivers/media/video/saa7114.o
CC [M] drivers/media/video/adv7170.o
LD [M] drivers/media/video/zr36067.o
CC [M] drivers/media/video/videocodec.o
CC [M] drivers/media/video/stradis.o
CC [M] drivers/media/video/cpia.o
CC [M] drivers/media/video/cpia_pp.o
CC [M] drivers/media/video/cpia_usb.o
CC [M] drivers/media/video/saa711x.o
CC [M] drivers/media/video/tvp5150.o
CC [M] drivers/media/video/wm8775.o
CC [M] drivers/media/video/cs53l32a.o
LD [M] drivers/media/video/tuner.o
CC [M] drivers/media/video/tda9840.o
CC [M] drivers/media/video/tea6415c.o
CC [M] drivers/media/video/tea6420.o
CC [M] drivers/media/video/mxb.o
CC [M] drivers/media/video/hexium_orion.o
CC [M] drivers/media/video/hexium_gemini.o
CC [M] drivers/media/video/dpc7146.o
CC [M] drivers/media/video/tuner-3036.o
CC [M] drivers/media/video/tda9887.o
CC [M] drivers/media/video/video-buf.o
CC [M] drivers/media/video/video-buf-dvb.o
CC [M] drivers/media/video/btcx-risc.o
CC [M] drivers/media/video/tveeprom.o
CC [M] drivers/media/video/saa7115.o
CC [M] drivers/media/video/saa7127.o
CC [M] drivers/media/video/cx88/cx88-video.o
CC [M] drivers/media/video/cx88/cx88-vbi.o
CC [M] drivers/media/video/cx88/cx88-mpeg.o
CC [M] drivers/media/video/cx88/cx88-cards.o
CC [M] drivers/media/video/cx88/cx88-core.o
CC [M] drivers/media/video/cx88/cx88-i2c.o
CC [M] drivers/media/video/cx88/cx88-tvaudio.o
CC [M] drivers/media/video/cx88/cx88-input.o
LD [M] drivers/media/video/cx88/cx88xx.o
LD [M] drivers/media/video/cx88/cx8800.o
LD [M] drivers/media/video/cx88/cx8802.o
CC [M] drivers/media/video/cx88/cx88-blackbird.o
CC [M] drivers/media/video/cx88/cx88-dvb.o
CC [M] drivers/media/video/cx88/cx88-alsa.o
CC [M] drivers/media/video/cx88/cx88-vp3054-i2c.o
CC [M] drivers/media/video/saa7134/saa7134-cards.o
CC [M] drivers/media/video/saa7134/saa7134-core.o
CC [M] drivers/media/video/saa7134/saa7134-i2c.o
CC [M] drivers/media/video/saa7134/saa7134-ts.o
CC [M] drivers/media/video/saa7134/saa7134-tvaudio.o
CC [M] drivers/media/video/saa7134/saa7134-vbi.o
CC [M] drivers/media/video/saa7134/saa7134-video.o
CC [M] drivers/media/video/saa7134/saa7134-input.o
LD [M] drivers/media/video/saa7134/saa7134.o
CC [M] drivers/media/video/saa7134/saa7134-empress.o
CC [M] drivers/media/video/saa7134/saa6752hs.o
CC [M] drivers/media/video/saa7134/saa7134-alsa.o
CC [M] drivers/media/video/saa7134/saa7134-dvb.o
CC [M] drivers/net/chelsio/cxgb2.o
CC [M] drivers/net/chelsio/espi.o
CC [M] drivers/net/chelsio/pm3393.o
CC [M] drivers/net/chelsio/sge.o
CC [M] drivers/net/chelsio/subr.o
CC [M] drivers/net/chelsio/mv88x201x.o
LD [M] drivers/net/chelsio/cxgb.o
Kernel: arch/x86_64/boot/bzImage is ready (#1)
Building modules, stage 2.
MODPOST
LD [M] drivers/ieee1394/ieee1394.ko
LD [M] drivers/md/dm-mirror.ko
LD [M] drivers/md/dm-mod.ko
LD [M] drivers/md/dm-multipath.ko
LD [M] drivers/md/dm-snapshot.ko
LD [M] drivers/md/raid6.ko
LD [M] drivers/media/video/adv7170.ko
LD [M] drivers/media/video/adv7175.ko
LD [M] drivers/media/video/bt819.ko
LD [M] drivers/media/video/bt856.ko
LD [M] drivers/media/video/btcx-risc.ko
LD [M] drivers/media/video/bttv.ko
LD [M] drivers/media/video/bw-qcam.ko
LD [M] drivers/media/video/c-qcam.ko
LD [M] drivers/media/video/compat_ioctl32.ko
LD [M] drivers/media/video/cpia.ko
LD [M] drivers/media/video/cpia_pp.ko
LD [M] drivers/media/video/cpia_usb.ko
LD [M] drivers/media/video/cs53l32a.ko
LD [M] drivers/media/video/cx88/cx88-alsa.ko
LD [M] drivers/media/video/cx88/cx88-blackbird.ko
LD [M] drivers/media/video/cx88/cx88-dvb.ko
LD [M] drivers/media/video/cx88/cx88-vp3054-i2c.ko
LD [M] drivers/media/video/cx88/cx8800.ko
LD [M] drivers/media/video/cx88/cx8802.ko
LD [M] drivers/media/video/cx88/cx88xx.ko
LD [M] drivers/media/video/dpc7146.ko
LD [M] drivers/media/video/hexium_gemini.ko
LD [M] drivers/media/video/hexium_orion.ko
LD [M] drivers/media/video/ir-kbd-i2c.ko
LD [M] drivers/media/video/msp3400.ko
LD [M] drivers/media/video/mxb.ko
LD [M] drivers/media/video/saa5246a.ko
LD [M] drivers/media/video/saa5249.ko
LD [M] drivers/media/video/saa6588.ko
LD [M] drivers/media/video/saa7110.ko
LD [M] drivers/media/video/saa7111.ko
LD [M] drivers/media/video/saa7114.ko
LD [M] drivers/media/video/saa7115.ko
LD [M] drivers/media/video/saa711x.ko
LD [M] drivers/media/video/saa7127.ko
LD [M] drivers/media/video/saa7134/saa6752hs.ko
LD [M] drivers/media/video/saa7134/saa7134-alsa.ko
LD [M] drivers/media/video/saa7134/saa7134-dvb.ko
LD [M] drivers/media/video/saa7134/saa7134-empress.ko
LD [M] drivers/media/video/saa7134/saa7134.ko
LD [M] drivers/media/video/saa7185.ko
LD [M] drivers/media/video/stradis.ko
LD [M] drivers/media/video/tda7432.ko
LD [M] drivers/media/video/tda9840.ko
LD [M] drivers/media/video/tda9875.ko
LD [M] drivers/media/video/tda9887.ko
LD [M] drivers/media/video/tea6415c.ko
LD [M] drivers/media/video/tea6420.ko
LD [M] drivers/media/video/tuner-3036.ko
LD [M] drivers/media/video/tuner.ko
LD [M] drivers/media/video/tvaudio.ko
LD [M] drivers/media/video/tveeprom.ko
LD [M] drivers/media/video/tvmixer.ko
LD [M] drivers/media/video/tvp5150.ko
LD [M] drivers/media/video/v4l1-compat.ko
LD [M] drivers/media/video/v4l2-common.ko
LD [M] drivers/media/video/video-buf-dvb.ko
LD [M] drivers/media/video/video-buf.ko
LD [M] drivers/media/video/videocodec.ko
LD [M] drivers/media/video/videodev.ko
LD [M] drivers/media/video/vpx3220.ko
LD [M] drivers/media/video/w9966.ko
LD [M] drivers/media/video/wm8775.ko
LD [M] drivers/media/video/zr36016.ko
LD [M] drivers/media/video/zr36050.ko
LD [M] drivers/media/video/zr36060.ko
LD [M] drivers/media/video/zr36067.ko
LD [M] drivers/net/chelsio/cxgb.ko
compiler@switch:/storage/linux-2.6.16-unmodified> make
CHK include/linux/version.h
CHK include/linux/compile.h
CHK usr/initramfs_list
Kernel: arch/x86_64/boot/bzImage is ready (#1)
Building modules, stage 2.
MODPOST
compiler@switch:/storage/linux-2.6.16-unmodified>
Regards,
Carl-Daniel
On Thu, Mar 30, 2006 at 01:55:55PM +0200, Carl-Daniel Hailfinger wrote:
> Hi,
>
> if I copy a compiled kernel tree to another location and run
> make again in the new directory, a few files always get rebuilt.
> These files only are rebuilt if the tree is a copy of another
> tree and they are rebuilt only once.
> Any ideas why this is the case?
The reason why the predictive rebuild happens is that in some parts
of the kbuild files it has been necessary to use absolute paths.
One example is the oiu2c shell script where we use the full path
to locate the shell script.
The reason why a full path is used is that this shall also work when
compiling the kernel using make O=...
What happens is that kbuild detects that the command used to build the
target has changed and therefore force a rebuild. It is the same
mechanishm that is used to detect when arguments to the compiler
changes.
So the rebuild will happen. It would be possible to minimize the places
where a rebuild is triggered when moving the source tree, but I have not
seen any benefit doing so lately.
Sam
Sam Ravnborg schrieb:
> On Thu, Mar 30, 2006 at 01:55:55PM +0200, Carl-Daniel Hailfinger wrote:
>
>>Hi,
>>
>>if I copy a compiled kernel tree to another location and run
>>make again in the new directory, a few files always get rebuilt.
>>These files only are rebuilt if the tree is a copy of another
>>tree and they are rebuilt only once.
>>Any ideas why this is the case?
>
> The reason why the predictive rebuild happens is that in some parts
> of the kbuild files it has been necessary to use absolute paths.
> One example is the oiu2c shell script where we use the full path
> to locate the shell script.
> The reason why a full path is used is that this shall also work when
> compiling the kernel using make O=...
Thanks for the information.
> So the rebuild will happen. It would be possible to minimize the places
> where a rebuild is triggered when moving the source tree, but I have not
> seen any benefit doing so lately.
Well, it would cause less confusion. It seems that ~90% of rebuilt files
are due to the following makefiles where full paths to includes are
specified:
./drivers/media/video/cx88/Makefile
./drivers/media/video/Makefile
./drivers/media/video/cx25840/Makefile
./drivers/media/video/saa7134/Makefile
./drivers/media/video/em28xx/Makefile
Any objections to fix these?
Regards,
Carl-Daniel
--
http://www.hailfinger.org/
On Thu, Mar 30, 2006 at 10:49:45PM +0200, Carl-Daniel Hailfinger wrote:
> Well, it would cause less confusion. It seems that ~90% of rebuilt files
> are due to the following makefiles where full paths to includes are
> specified:
> ./drivers/media/video/cx88/Makefile
> ./drivers/media/video/Makefile
> ./drivers/media/video/cx25840/Makefile
> ./drivers/media/video/saa7134/Makefile
> ./drivers/media/video/em28xx/Makefile
>
> Any objections to fix these?
Care to send a path - then I will include it with next kbuild update.
Sam