Messages in this thread | | | Date | Wed, 5 Aug 2009 09:43:42 -0400 | From | Neil Horman <> | Subject | Re: [Patch 2/7] x86: implement crashkernel=auto |
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On Wed, Aug 05, 2009 at 07:19:22AM -0400, Amerigo Wang wrote: > > Implement "crashkernel=auto" for x86 first, other arch will be added in the > following patches. > > Signed-off-by: WANG Cong <amwang@redhat.com> > > --- > Index: linux-2.6/kernel/kexec.c > =================================================================== > --- linux-2.6.orig/kernel/kexec.c > +++ linux-2.6/kernel/kexec.c > @@ -37,6 +37,7 @@ > #include <asm/io.h> > #include <asm/system.h> > #include <asm/sections.h> > +#include <asm/setup.h> > > /* Per cpu memory for storing cpu states in case of system crash. */ > note_buf_t* crash_notes; > @@ -1297,6 +1298,38 @@ int __init parse_crashkernel(char *cm > > ck_cmdline += 12; /* strlen("crashkernel=") */ > > +#ifdef CONFIG_KEXEC_AUTO_RESERVE > + if (strncmp(ck_cmdline, "auto", 4) == 0) { > + unsigned long long size; > + char tmp[32]; > + > + size = arch_default_crash_size(system_ram); > + if (size != 0) { > + *crash_size = size; > + *crash_base = arch_default_crash_base(); > + size = scnprintf(tmp, sizeof(tmp), "%luM@%luM", > + (unsigned long)(*crash_size)>>20, > + (unsigned long)(*crash_base)>>20); > + /* size can't be <= 4. */ > + if (likely((size - 4 + strlen(cmdline)) > + < COMMAND_LINE_SIZE - 1)) { > + memmove(ck_cmdline + size, ck_cmdline + 4, > + strlen(cmdline) - (ck_cmdline + 4 - cmdline) + 1); > + memcpy(ck_cmdline, tmp, size); > + } > + return 0; > + } else { > + /* > + * We can't reserve memory auotmatcally, > + * remove "crashkernel=" from cmdline. > + */ > + ck_cmdline += 4; /* strlen("auto") */ > + memmove(ck_cmdline - 16, ck_cmdline, > + strlen(cmdline) - (ck_cmdline - cmdline) + 1); > + return -ENOMEM; > + } > + } > +#endif > /* > * if the commandline contains a ':', then that's the extended > * syntax -- if not, it must be the classic syntax > Index: linux-2.6/arch/x86/include/asm/kexec.h > =================================================================== > --- linux-2.6.orig/arch/x86/include/asm/kexec.h > +++ linux-2.6/arch/x86/include/asm/kexec.h > @@ -61,6 +61,29 @@ > # define KEXEC_ARCH KEXEC_ARCH_X86_64 > #endif > > +#ifdef CONFIG_KEXEC_AUTO_RESERVE > +#ifndef KEXEC_AUTO_RESERVED_SIZE > +#define KEXEC_AUTO_RESERVED_SIZE 1ULL<<27 /* 128M */ > +#endif > +#ifndef KEXEC_AUTO_THRESHOLD > +#define KEXEC_AUTO_THRESHOLD 1ULL<<32 /* 4G */ > +#endif > +static inline > +unsigned long long arch_default_crash_size(unsigned long long total_size) > +{ > + if (total_size < KEXEC_AUTO_THRESHOLD) > + return 0; > + else > + return KEXEC_AUTO_RESERVED_SIZE; > +} > +static inline > +unsigned long long arch_default_crash_base(void) > +{ > + /* On x86, 0 means find the base address automatically. */ > + return 0; > +} > +#endif > + > /* > * CPU does not save ss and sp on stack if execution is already > * running in kernel mode at the time of NMI occurrence. This code
What about all the other arches that support kexec? ia64/ppc[64]/s390/etc? Don't they need an implementation of arch_default_crash_size? Or perhaps better still you should put this definition in asm-generic, so that it can be overridden per-arch if need be, but you always have something to fall back on.
Neil
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