Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-06-03 Thread Michael Holzheu
On Mon, 3 Jun 2013 11:59:40 -0400 Vivek Goyal wrote: > On Mon, Jun 03, 2013 at 03:27:18PM +0200, Michael Holzheu wrote: > > [..] > > > If not, how would remap_pfn_range() work with HSA region when > > > /proc/vmcore is mmaped()? > > > > I am no memory management expert, so I discussed that

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-06-03 Thread Vivek Goyal
On Mon, Jun 03, 2013 at 03:27:18PM +0200, Michael Holzheu wrote: [..] > > If not, how would remap_pfn_range() work with HSA region when > > /proc/vmcore is mmaped()? > > I am no memory management expert, so I discussed that with Martin > Schwidefsky (s390 architecture maintainer). Perhaps

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-06-03 Thread Michael Holzheu
On Fri, 31 May 2013 12:01:58 -0400 Vivek Goyal wrote: > On Fri, May 31, 2013 at 04:21:27PM +0200, Michael Holzheu wrote: > > On Thu, 30 May 2013 16:38:47 -0400 > > Vivek Goyal wrote: > > > > > On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: > > > [...] > > For zfcpdump

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-06-03 Thread Michael Holzheu
On Fri, 31 May 2013 12:01:58 -0400 Vivek Goyal vgo...@redhat.com wrote: On Fri, May 31, 2013 at 04:21:27PM +0200, Michael Holzheu wrote: On Thu, 30 May 2013 16:38:47 -0400 Vivek Goyal vgo...@redhat.com wrote: On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: [...]

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-06-03 Thread Vivek Goyal
On Mon, Jun 03, 2013 at 03:27:18PM +0200, Michael Holzheu wrote: [..] If not, how would remap_pfn_range() work with HSA region when /proc/vmcore is mmaped()? I am no memory management expert, so I discussed that with Martin Schwidefsky (s390 architecture maintainer). Perhaps something

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-06-03 Thread Michael Holzheu
On Mon, 3 Jun 2013 11:59:40 -0400 Vivek Goyal vgo...@redhat.com wrote: On Mon, Jun 03, 2013 at 03:27:18PM +0200, Michael Holzheu wrote: [..] If not, how would remap_pfn_range() work with HSA region when /proc/vmcore is mmaped()? I am no memory management expert, so I discussed that

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-31 Thread Vivek Goyal
On Fri, May 31, 2013 at 04:21:27PM +0200, Michael Holzheu wrote: > On Thu, 30 May 2013 16:38:47 -0400 > Vivek Goyal wrote: > > > On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: > > > > [..] > > > >>> START QUOTE > > > > > > [PATCH v3 1/3] kdump: Introduce ELF header in new

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-31 Thread Michael Holzheu
On Thu, 30 May 2013 16:38:47 -0400 Vivek Goyal wrote: > On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: > > [..] > > >>> START QUOTE > > > > [PATCH v3 1/3] kdump: Introduce ELF header in new memory feature > > > > Currently for s390 we create the ELF core header in the 2nd

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-31 Thread Michael Holzheu
On Thu, 30 May 2013 16:38:47 -0400 Vivek Goyal vgo...@redhat.com wrote: On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: [..] START QUOTE [PATCH v3 1/3] kdump: Introduce ELF header in new memory feature Currently for s390 we create the ELF core header in the 2nd

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-31 Thread Vivek Goyal
On Fri, May 31, 2013 at 04:21:27PM +0200, Michael Holzheu wrote: On Thu, 30 May 2013 16:38:47 -0400 Vivek Goyal vgo...@redhat.com wrote: On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: [..] START QUOTE [PATCH v3 1/3] kdump: Introduce ELF header in new memory

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-30 Thread Vivek Goyal
On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: [..] > >>> START QUOTE > > [PATCH v3 1/3] kdump: Introduce ELF header in new memory feature > > Currently for s390 we create the ELF core header in the 2nd kernel with > a small trick. We relocate the addresses in the ELF header

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-30 Thread Vivek Goyal
On Wed, May 29, 2013 at 07:12:49PM +0200, Michael Holzheu wrote: [..] > > > > So are you saying that s390 is ready to switch to mechanism of > > > > creating ELF headers in first kernel by kexec-tools and new kernel > > > > does not have to preare ELF headers? > > > > > > No, I meant that

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-30 Thread Vivek Goyal
On Wed, May 29, 2013 at 07:12:49PM +0200, Michael Holzheu wrote: [..] So are you saying that s390 is ready to switch to mechanism of creating ELF headers in first kernel by kexec-tools and new kernel does not have to preare ELF headers? No, I meant that currently nobody is

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-30 Thread Vivek Goyal
On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: [..] START QUOTE [PATCH v3 1/3] kdump: Introduce ELF header in new memory feature Currently for s390 we create the ELF core header in the 2nd kernel with a small trick. We relocate the addresses in the ELF header in a way

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-29 Thread Michael Holzheu
On Wed, 29 May 2013 12:23:26 -0400 Vivek Goyal wrote: > On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: > > On Tue, 28 May 2013 09:55:01 -0400 > > Vivek Goyal wrote: > > > > > On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: > > > > [snip] > > > > > > Besides

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-29 Thread Vivek Goyal
On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: > On Tue, 28 May 2013 09:55:01 -0400 > Vivek Goyal wrote: > > > On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: > > [snip] > > > > Besides of the newmem mechanism, for completeness, we also > > > implemented the

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-29 Thread Michael Holzheu
On Tue, 28 May 2013 09:55:01 -0400 Vivek Goyal wrote: > On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: [snip] > > Besides of the newmem mechanism, for completeness, we also > > implemented the oldmem ELF header mechansim in kexec. But this is > > disabled by default. > > > >

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-29 Thread Michael Holzheu
On Tue, 28 May 2013 09:55:01 -0400 Vivek Goyal vgo...@redhat.com wrote: On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: [snip] Besides of the newmem mechanism, for completeness, we also implemented the oldmem ELF header mechansim in kexec. But this is disabled by

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-29 Thread Vivek Goyal
On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: On Tue, 28 May 2013 09:55:01 -0400 Vivek Goyal vgo...@redhat.com wrote: On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: [snip] Besides of the newmem mechanism, for completeness, we also implemented

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-29 Thread Michael Holzheu
On Wed, 29 May 2013 12:23:26 -0400 Vivek Goyal vgo...@redhat.com wrote: On Wed, May 29, 2013 at 01:51:44PM +0200, Michael Holzheu wrote: On Tue, 28 May 2013 09:55:01 -0400 Vivek Goyal vgo...@redhat.com wrote: On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: [snip]

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-28 Thread Vivek Goyal
On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: [..] > Therefore, if necessary, IMHO we can switch to the ELF header memory > swap mechanism for s390 in the kernel. Of course we would then also > have to adjust the (disabled) kexec code. I think it is a good idea to fix it in

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-28 Thread Vivek Goyal
On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: > On Sat, 25 May 2013 16:31:58 +0800 > Zhang Yanfei wrote: > > [snip] > > > For s390, if we put swap info into the elf header, This will > > change /sbin/kexec. But at this point, copy_oldmem_page is still > > doing the swap when

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-28 Thread Vivek Goyal
On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: On Sat, 25 May 2013 16:31:58 +0800 Zhang Yanfei zhangyanfei@gmail.com wrote: [snip] For s390, if we put swap info into the elf header, This will change /sbin/kexec. But at this point, copy_oldmem_page is still doing

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-28 Thread Vivek Goyal
On Sat, May 25, 2013 at 02:52:17PM +0200, Michael Holzheu wrote: [..] Therefore, if necessary, IMHO we can switch to the ELF header memory swap mechanism for s390 in the kernel. Of course we would then also have to adjust the (disabled) kexec code. I think it is a good idea to fix it in s390

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Eric W. Biederman
Zhang Yanfei writes: > 于 2013年05月25日 11:01, Eric W. Biederman 写道: >> Zhang Yanfei writes: >> >>> Hello Eric, >>> The function copy_oldmem_page also concerns me. I don't have a clue why we duplicate that function on every architecutre in a slightly different form. There should

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Michael Holzheu
On Fri, 24 May 2013 13:05:07 -0400 Vivek Goyal wrote: > On Fri, May 24, 2013 at 06:46:53PM +0200, Michael Holzheu wrote: > > On Fri, 24 May 2013 11:28:49 -0400 > > Vivek Goyal wrote: > > > > > On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: > > > > [snip] > > > > > As

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Michael Holzheu
On Sat, 25 May 2013 16:31:58 +0800 Zhang Yanfei wrote: [snip] > For s390, if we put swap info into the elf header, This will > change /sbin/kexec. But at this point, copy_oldmem_page is still > doing the swap when we try to read the pages among [0 - OLDMEM_SIZE] > and [OLDMEM_BASE - OLDMEM_BASE

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Zhang Yanfei
于 2013年05月25日 11:01, Eric W. Biederman 写道: > Zhang Yanfei writes: > >> Hello Eric, >> >>> The function copy_oldmem_page also concerns me. I don't have a clue why >>> we duplicate that function on every architecutre in a slightly different >>> form. There should be enough abstractions in the

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Zhang Yanfei
于 2013年05月25日 11:01, Eric W. Biederman 写道: Zhang Yanfei zhangyanfei@gmail.com writes: Hello Eric, The function copy_oldmem_page also concerns me. I don't have a clue why we duplicate that function on every architecutre in a slightly different form. There should be enough abstractions

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Michael Holzheu
On Sat, 25 May 2013 16:31:58 +0800 Zhang Yanfei zhangyanfei@gmail.com wrote: [snip] For s390, if we put swap info into the elf header, This will change /sbin/kexec. But at this point, copy_oldmem_page is still doing the swap when we try to read the pages among [0 - OLDMEM_SIZE] and

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Michael Holzheu
On Fri, 24 May 2013 13:05:07 -0400 Vivek Goyal vgo...@redhat.com wrote: On Fri, May 24, 2013 at 06:46:53PM +0200, Michael Holzheu wrote: On Fri, 24 May 2013 11:28:49 -0400 Vivek Goyal vgo...@redhat.com wrote: On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: [snip]

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-25 Thread Eric W. Biederman
Zhang Yanfei zhangyanfei@gmail.com writes: 于 2013年05月25日 11:01, Eric W. Biederman 写道: Zhang Yanfei zhangyanfei@gmail.com writes: Hello Eric, The function copy_oldmem_page also concerns me. I don't have a clue why we duplicate that function on every architecutre in a slightly

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Eric W. Biederman
Zhang Yanfei writes: > Hello Eric, > >> The function copy_oldmem_page also concerns me. I don't have a clue why >> we duplicate that function on every architecutre in a slightly different >> form. There should be enough abstractions in the kernel to make that >> unnecessary. I would be glad

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Zhang Yanfei
Hello Eric, 于 2013年05月25日 06:44, Eric W. Biederman 写道: > Vivek Goyal writes: > >> On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: >>> Hello Vivek, >>> >>> On Fri, 24 May 2013 10:36:44 -0400 >>> Vivek Goyal wrote: >>> >>> [snip] >>> Sorry, I don't understand the problem.

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Eric W. Biederman
Vivek Goyal writes: > On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: >> Hello Vivek, >> >> On Fri, 24 May 2013 10:36:44 -0400 >> Vivek Goyal wrote: >> >> [snip] >> >> > Sorry, I don't understand the problem. If we swapped low memory and >> > crash reserved memory, that

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Vivek Goyal
On Fri, May 24, 2013 at 06:46:53PM +0200, Michael Holzheu wrote: > On Fri, 24 May 2013 11:28:49 -0400 > Vivek Goyal wrote: > > > On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: > > [snip] > > > As /proc/vmcore is the most used and useful interface, I prefer that > > we swap

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Michael Holzheu
On Fri, 24 May 2013 11:28:49 -0400 Vivek Goyal wrote: > On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: [snip] > As /proc/vmcore is the most used and useful interface, I prefer that > we swap memory and put that info in elf headers. For /dev/oldme, I > don't mind if we leave

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Vivek Goyal
On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: > Hello Vivek, > > On Fri, 24 May 2013 10:36:44 -0400 > Vivek Goyal wrote: > > [snip] > > > Sorry, I don't understand the problem. If we swapped low memory and > > crash reserved memory, that should have been taken care by

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Michael Holzheu
Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal wrote: [snip] > Sorry, I don't understand the problem. If we swapped low memory and > crash reserved memory, that should have been taken care by prepared > ELF headers so that we map the right pfns. In x86 we swap 640K of low > memory

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Vivek Goyal
On Fri, May 24, 2013 at 03:08:07PM +0200, Michael Holzheu wrote: > Hello Vivek and Hatayama, > > Currently the /proc/vmcore mmap patches are not working on s390. The > problem is that on s390 the kernel in not relocatable and therefore > always runs in the lower memory area. Therefore for kdump

[PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Michael Holzheu
Hello Vivek and Hatayama, Currently the /proc/vmcore mmap patches are not working on s390. The problem is that on s390 the kernel in not relocatable and therefore always runs in the lower memory area. Therefore for kdump on s390 we swap the lower memory area with the crashkernel area before

[PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Michael Holzheu
Hello Vivek and Hatayama, Currently the /proc/vmcore mmap patches are not working on s390. The problem is that on s390 the kernel in not relocatable and therefore always runs in the lower memory area. Therefore for kdump on s390 we swap the lower memory area with the crashkernel area before

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Vivek Goyal
On Fri, May 24, 2013 at 03:08:07PM +0200, Michael Holzheu wrote: Hello Vivek and Hatayama, Currently the /proc/vmcore mmap patches are not working on s390. The problem is that on s390 the kernel in not relocatable and therefore always runs in the lower memory area. Therefore for kdump on

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Michael Holzheu
Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal vgo...@redhat.com wrote: [snip] Sorry, I don't understand the problem. If we swapped low memory and crash reserved memory, that should have been taken care by prepared ELF headers so that we map the right pfns. In x86 we swap 640K

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Vivek Goyal
On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal vgo...@redhat.com wrote: [snip] Sorry, I don't understand the problem. If we swapped low memory and crash reserved memory, that should have been taken care by

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Michael Holzheu
On Fri, 24 May 2013 11:28:49 -0400 Vivek Goyal vgo...@redhat.com wrote: On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: [snip] As /proc/vmcore is the most used and useful interface, I prefer that we swap memory and put that info in elf headers. For /dev/oldme, I don't mind

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Vivek Goyal
On Fri, May 24, 2013 at 06:46:53PM +0200, Michael Holzheu wrote: On Fri, 24 May 2013 11:28:49 -0400 Vivek Goyal vgo...@redhat.com wrote: On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: [snip] As /proc/vmcore is the most used and useful interface, I prefer that we

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Eric W. Biederman
Vivek Goyal vgo...@redhat.com writes: On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal vgo...@redhat.com wrote: [snip] Sorry, I don't understand the problem. If we swapped low memory and crash reserved

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Zhang Yanfei
Hello Eric, 于 2013年05月25日 06:44, Eric W. Biederman 写道: Vivek Goyal vgo...@redhat.com writes: On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: Hello Vivek, On Fri, 24 May 2013 10:36:44 -0400 Vivek Goyal vgo...@redhat.com wrote: [snip] Sorry, I don't understand the

Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390

2013-05-24 Thread Eric W. Biederman
Zhang Yanfei zhangyanfei@gmail.com writes: Hello Eric, The function copy_oldmem_page also concerns me. I don't have a clue why we duplicate that function on every architecutre in a slightly different form. There should be enough abstractions in the kernel to make that unnecessary. I