fadvise doesn't work well.

In attanchment.

root@kernel:~/Documents/mm/tools/linux-ftools# dd if=../../../images/ubuntu-11.04-desktop-i386.iso of=/tmpfs
1403484+0 records in
1403484+0 records out
718583808 bytes (719 MB) copied, 19.5054 s, 36.8 MB/s
root@kernel:~/Documents/mm/tools/linux-ftools# ./linux-fincore -s ../../../images/ubuntu-11.04-desktop-i386.iso 
filename                                                                                       size        total_pages    min_cached page       cached_pages        cached_size        cached_perc
--------                                                                                       ----        -----------    ---------------       ------------        -----------        -----------
../../../images/ubuntu-11.04-desktop-i386.iso                                             718583808             175436                  0             175436          718585856             100.00
---
total cached size: 718585856
root@kernel:~/Documents/mm/tools/linux-ftools# ./linux-fadvise ../../../images/ubuntu-11.04-desktop-i386.iso DONTNEED 0,718585856
Going to fadvise ../../../images/ubuntu-11.04-desktop-i386.iso as mode DONTNEED
offset: 0
length: 718583808
Invalid mode DONTNEED
root@kernel:~/Documents/mm/tools/linux-ftools# ./linux-fincore -s ../../../images/ubuntu-11.04-desktop-i386.iso 
filename                                                                                       size        total_pages    min_cached page       cached_pages        cached_size        cached_perc
--------                                                                                       ----        -----------    ---------------       ------------        -----------        -----------
../../../images/ubuntu-11.04-desktop-i386.iso                                             718583808             175436                  0             175436          718585856             100.00
---
total cached size: 718585856

Hi Simon,

Try run "sync" before doing fadvise, because fadvise won't drop dirty/writeback/mapped pages.

Thanks,
Fengguang

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Hi Fengguang,

Thanks for your quick response. But the result is the same in attachment.

The pages of ../../../images/ubuntu-11.04-desktop-i386.iso is mapped or unmapped?

root@kernel:~/Documents/mm/tools/linux-ftools# dd if=../../../images/ubuntu-11.04-desktop-i386.iso of=/tmpfs
1403484+0 records in
1403484+0 records out
718583808 bytes (719 MB) copied, 35.5144 s, 20.2 MB/s
root@hacker:~/Documents/mm/tools/linux-ftools# ./linux-fincore -s ../../../images/ubuntu-11.04-desktop-i386.iso
filename                                                                                       size        total_pages    min_cached page       cached_pages        cached_size        cached_perc
--------                                                                                       ----        -----------    ---------------       ------------        -----------        -----------
../../../images/ubuntu-11.04-desktop-i386.iso                                             718583808             175436                  0             175436          718585856             100.00
---
total cached size: 718585856
root@kernel:~/Documents/mm/tools/linux-ftools# sync
root@kernel:~/Documents/mm/tools/linux-ftools# ./linux-fincore -s ../../../images/ubuntu-11.04-desktop-i386.iso
filename                                                                                       size        total_pages    min_cached page       cached_pages        cached_size        cached_perc
--------                                                                                       ----        -----------    ---------------       ------------        -----------        -----------
../../../images/ubuntu-11.04-desktop-i386.iso                                             718583808             175436                  0             175436          718585856             100.00
---
total cached size: 718585856
root@kernel:~/Documents/mm/tools/linux-ftools# ./linux-fadvise ../../../images/ubuntu-11.04-desktop-i386.iso DONTNEED 0,718585856
Going to fadvise ../../../images/ubuntu-11.04-desktop-i386.iso as mode DONTNEED
offset: 0
length: 718583808
Invalid mode DONTNEED
root@kernel:~/Documents/mm/tools/linux-ftools# ./linux-fincore -s ../../../images/ubuntu-11.04-desktop-i386.iso
filename                                                                                       size        total_pages    min_cached page       cached_pages        cached_size        cached_perc
--------                                                                                       ----        -----------    ---------------       ------------        -----------        -----------
../../../images/ubuntu-11.04-desktop-i386.iso                                             718583808             175436                  0             175436          718585856             100.00
---
total cached size: 718585856

You may check if anyone is using (hence possibly mapping) it with

        lsof | grep ubuntu-11.04-desktop-i386.iso

Thanks,
Fengguang

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~~~~~~~~~~~~~~~~~~~~~~~

Oops, that's invalid command. Use "dontneed" rather than "DONTNEED".

fadvise is case sensitive..

Thanks,
Fengguang

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