Re: [PATCH] mm: disallow direct reclaim page writeback

[Minchan Kim]

On Wed, Apr 14, 2010 at 2:54 PM, KOSAKI Motohiro
<kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>> On Wed, Apr 14, 2010 at 01:59:45PM +0900, KAMEZAWA Hiroyuki wrote:
>> > On Wed, 14 Apr 2010 11:40:41 +1000
>> > Dave Chinner <david@xxxxxxxxxxxxx> wrote:
>> >
>> > > Â50) Â Â 3168 Â Â Â64 Â xfs_vm_writepage+0xab/0x160 [xfs]
>> > > Â51) Â Â 3104 Â Â 384 Â shrink_page_list+0x65e/0x840
>> > > Â52) Â Â 2720 Â Â 528 Â shrink_zone+0x63f/0xe10
>> >
>> > A bit OFF TOPIC.
>> >
>> > Could you share disassemble of shrink_zone() ?
>> >
>> > In my environ.
>> > 00000000000115a0 <shrink_zone>:
>> >  Â115a0:    55           Âpush  %rbp
>> >  Â115a1:    48 89 e5        Âmov  Â%rsp,%rbp
>> >  Â115a4:    41 57          push  %r15
>> >  Â115a6:    41 56          push  %r14
>> >  Â115a8:    41 55          push  %r13
>> >  Â115aa:    41 54          push  %r12
>> >  Â115ac:    53           Âpush  %rbx
>> >  Â115ad:    48 83 ec 78       sub  Â$0x78,%rsp
>> > Â Â115b1: Â Â Â e8 00 00 00 00 Â Â Â Â Âcallq Â115b6 <shrink_zone+0x16>
>> >  Â115b6:    48 89 75 80       mov  Â%rsi,-0x80(%rbp)
>> >
>> > disassemble seems to show 0x78 bytes for stack. And no changes to %rsp
>> > until retrun.
>>
>> I see the same. I didn't compile those kernels, though. IIUC,
>> they were built through the Ubuntu build infrastructure, so there is
>> something different in terms of compiler, compiler options or config
>> to what we are both using. Most likely it is the compiler inlining,
>> though Chris's patches to prevent that didn't seem to change the
>> stack usage.
>>
>> I'm trying to get a stack trace from the kernel that has shrink_zone
>> in it, but I haven't succeeded yet....
>
> I also got 0x78 byte stack usage. Umm.. Do we discussed real issue now?
>

In my case, 0x110 byte in 32 bit machine.
I think it's possible in 64 bit machine.

00001830 <shrink_zone>:
    1830:       55                      push   %ebp
    1831:       89 e5                   mov    %esp,%ebp
    1833:       57                      push   %edi
    1834:       56                      push   %esi
    1835:       53                      push   %ebx
    1836:       81 ec 10 01 00 00       sub    $0x110,%esp
    183c:       89 85 24 ff ff ff       mov    %eax,-0xdc(%ebp)
    1842:       89 95 20 ff ff ff       mov    %edx,-0xe0(%ebp)
    1848:       89 8d 1c ff ff ff       mov    %ecx,-0xe4(%ebp)
    184e:       8b 41 04                mov    0x4(%ecx)

my gcc is following as.

barrios@barriostarget:~/mmotm$ gcc -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
4.3.3-5ubuntu4'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--with-gxx-include-dir=/usr/include/c++/4.3 --program-suffix=-4.3
--enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc
--enable-mpfr --enable-targets=all --with-tune=generic
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)


Is it depends on config?
I attach my config.

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-- 
Kind regards,
Minchan Kim

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