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Message-ID: <u2g28c262361004140316l547b9d6cka3bdb2d738b6ad67@mail.gmail.com> Date: Wed, 14 Apr 2010 19:16:36 +0900 From: Minchan Kim <minchan.kim@...il.com> To: Mel Gorman <mel@....ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>, KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, Dave Chinner <david@...morbit.com>, Chris Mason <chris.mason@...cle.com>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, linux-fsdevel@...r.kernel.org Subject: Re: [PATCH] mm: disallow direct reclaim page writeback On Wed, Apr 14, 2010 at 7:07 PM, Mel Gorman <mel@....ul.ie> wrote: > On Wed, Apr 14, 2010 at 07:01:47PM +0900, Minchan Kim wrote: >> >> >>> > Dave Chinner <david@...morbit.com> wrote: >> >> >>> > >> >> >>> > > 50) 3168 64 xfs_vm_writepage+0xab/0x160 [xfs] >> >> >>> > > 51) 3104 384 shrink_page_list+0x65e/0x840 >> >> >>> > > 52) 2720 528 shrink_zone+0x63f/0xe10 >> >> >>> > >> >> >>> > A bit OFF TOPIC. >> >> >>> > >> >> >>> > Could you share disassemble of shrink_zone() ? >> >> >>> > >> >> >>> > In my environ. >> >> >>> > 00000000000115a0 <shrink_zone>: >> >> >>> > 115a0: 55 push %rbp >> >> >>> > 115a1: 48 89 e5 mov %rsp,%rbp >> >> >>> > 115a4: 41 57 push %r15 >> >> >>> > 115a6: 41 56 push %r14 >> >> >>> > 115a8: 41 55 push %r13 >> >> >>> > 115aa: 41 54 push %r12 >> >> >>> > 115ac: 53 push %rbx >> >> >>> > 115ad: 48 83 ec 78 sub $0x78,%rsp >> >> >>> > 115b1: e8 00 00 00 00 callq 115b6 <shrink_zone+0x16> >> >> >>> > 115b6: 48 89 75 80 mov %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 $0x110,%esp >> >> > 183c: 89 85 24 ff ff ff mov %eax,-0xdc(%ebp) >> >> > 1842: 89 95 20 ff ff ff mov %edx,-0xe0(%ebp) >> >> > 1848: 89 8d 1c ff ff ff mov %ecx,-0xe4(%ebp) >> >> > 184e: 8b 41 04 mov 0x4(%ecx) >> >> > >> >> > my gcc is following as. >> >> > >> >> > barrios@...riostarget:~/mmotm$ 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. >> >> >> >> I changed shrink list by noinline_for_stack. >> >> The result is following as. >> >> >> >> >> >> 00001fe0 <shrink_zone>: >> >> 1fe0: 55 push %ebp >> >> 1fe1: 89 e5 mov %esp,%ebp >> >> 1fe3: 57 push %edi >> >> 1fe4: 56 push %esi >> >> 1fe5: 53 push %ebx >> >> 1fe6: 83 ec 4c sub $0x4c,%esp >> >> 1fe9: 89 45 c0 mov %eax,-0x40(%ebp) >> >> 1fec: 89 55 bc mov %edx,-0x44(%ebp) >> >> 1fef: 89 4d b8 mov %ecx,-0x48(%ebp) >> >> >> >> 0x110 -> 0x4c. >> >> >> >> Should we have to add noinline_for_stack for shrink_list? >> >> >> > >> > Hmm. about shirnk_zone(), I don't think uninlining functions directly called >> > by shrink_zone() can be a help. >> > Total stack size of call-chain will be still big. >> >> Absolutely. >> But above 500 byte usage is one of hogger and uninlining is not >> critical about reclaim performance. So I think we don't get any lost >> than gain. >> > > Beat in mind that uninlining can slightly increase the stack usage in some > cases because arguments, return addresses and the like have to be pushed > onto the stack. Inlining or unlining is only the answer when it reduces the > number of stack variables that exist at any given time. Yes. I totally have missed it. Thanks, Mel. -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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