[PATCH] makedumpfile/arm64: Add '--mem-usage' support

Bhupesh SHARMA bhupesh.linux at gmail.com
Wed Feb 21 10:57:52 PST 2018


Hi Masaki Tachibana,

On Tue, Feb 20, 2018 at 4:42 PM, Masaki Tachibana
<mas-tachibana at vf.jp.nec.com> wrote:
> Hi Bhupesh,
>
> Sorry for the late reply.
> I'll reply by the end the next week.

Sure. Thanks for your mail.

Regards,
Bhupesh


> Thanks
> tachibana
>
>> -----Original Message-----
>> From: Bhupesh Sharma [mailto:bhsharma at redhat.com]
>> Sent: Tuesday, February 20, 2018 1:56 PM
>> To: kexec at lists.infradead.org
>> Cc: Bhupesh Sharma <bhsharma at redhat.com>; Tachibana Masaki() <mas-tachibana at vf.jp.nec.com>; Nakayama Takuya(
>> ) <tak-nakayama at tg.jp.nec.com>; Nishimura Daisuke() <dai-nishimura at rc.jp.nec.com>
>> Subject: Re: [PATCH] makedumpfile/arm64: Add '--mem-usage' support
>>
>> Hello,
>>
>> On Fri, Feb 9, 2018 at 3:06 PM, Bhupesh Sharma <bhsharma at redhat.com> wrote:
>> > Its good to have the makedumpfile '--mem-usage' support
>> > for arm64 architecture as well, as it allows one to see the page numbers
>> > of current system (1st kernel) in different use.
>> >
>> > Using this we can know how many pages are dumpable when different
>> > dump_level is specified.
>> >
>> > Normally for x86_64, makedumpfile analyzes the 'System Ram' and
>> > 'kernel text' program segment of /proc/kcore excluding
>> > the crashkernel range, then calculates the page number of different
>> > kind per vmcoreinfo.
>> >
>> > We use the similar logic for arm64, but in addition make the '--mem-usage'
>> > usage dependent on the VMLINUX file being passed. This is done to allow
>> > information like VA_BITS being determined from kernel symbol like
>> > _stext. This allows us to get the VA_BITS before 'set_kcore_vmcoreinfo()'
>> > is called.
>> >
>> > Also I have validated the '--mem-usage' makedumpfile option on several
>> > ppc64/ppc64le and s390x machines, so update the makedumpfile.8
>> > documentation to indicate that '--mem-usage' option is supported
>> > not only on x86_64, but also on ppc64, s390x and arm64.
>> >
>> > After this patch, when using the '--mem-usage' option with makedumpfile,
>> > we get the correct information about the different pages. For e.g.
>> > here is an output from my arm64 board:
>> >
>> > TYPE            PAGES                   EXCLUDABLE      DESCRIPTION
>> > ----------------------------------------------------------------------
>> > ZERO            49524                   yes             Pages filled with zero
>> > NON_PRI_CACHE   15143                   yes             Cache pages without private flag
>> > PRI_CACHE       29147                   yes             Cache pages with private flag
>> > USER            3684                    yes             User process pages
>> > FREE            1450569                 yes             Free pages
>> > KERN_DATA       14243                   no              Dumpable kernel data
>> >
>> > page size:              65536
>> > Total pages on system:  1562310
>> > Total size on system:   102387548160     Byte
>> >
>> > Cc: Masaki Tachibana <mas-tachibana at vf.jp.nec.com>
>> > Cc: Takuya Nakayama <tak-nakayama at tg.jp.nec.com>
>> > Cc: Daisuke Nishimura <dai-nishimura at rc.jp.nec.com>
>> > Signed-off-by: Bhupesh Sharma <bhsharma at redhat.com>
>>
>> Ping. Any review comments on this?
>>
>> Regards,
>> Bhupesh
>>
>> > ---
>> >  arch/arm64.c   | 51 ++++++++++++++++++++++++++++++++++++++++++++++++---
>> >  makedumpfile.8 | 11 +++++++++--
>> >  makedumpfile.c | 25 +++++++++++++++++++++++--
>> >  makedumpfile.h |  1 +
>> >  4 files changed, 81 insertions(+), 7 deletions(-)
>> >
>> > diff --git a/arch/arm64.c b/arch/arm64.c
>> > index 25d7a1f4db98..91f113f6447c 100644
>> > --- a/arch/arm64.c
>> > +++ b/arch/arm64.c
>> > @@ -48,6 +48,12 @@ static unsigned long kimage_voffset;
>> >  #define SZ_64K                 (64 * 1024)
>> >  #define SZ_128M                        (128 * 1024 * 1024)
>> >
>> > +#define PAGE_OFFSET_36 ((0xffffffffffffffffUL) << 36)
>> > +#define PAGE_OFFSET_39 ((0xffffffffffffffffUL) << 39)
>> > +#define PAGE_OFFSET_42 ((0xffffffffffffffffUL) << 42)
>> > +#define PAGE_OFFSET_47 ((0xffffffffffffffffUL) << 47)
>> > +#define PAGE_OFFSET_48 ((0xffffffffffffffffUL) << 48)
>> > +
>> >  #define pgd_val(x)             ((x).pgd)
>> >  #define pud_val(x)             (pgd_val((x).pgd))
>> >  #define pmd_val(x)             (pud_val((x).pud))
>> > @@ -140,8 +146,6 @@ pud_offset(pgd_t *pgda, pgd_t *pgdv, unsigned long vaddr)
>> >
>> >  static int calculate_plat_config(void)
>> >  {
>> > -       va_bits = NUMBER(VA_BITS);
>> > -
>> >         /* derive pgtable_level as per arch/arm64/Kconfig */
>> >         if ((PAGESIZE() == SZ_16K && va_bits == 36) ||
>> >                         (PAGESIZE() == SZ_64K && va_bits == 42)) {
>> > @@ -188,7 +192,6 @@ get_machdep_info_arm64(void)
>> >         kimage_voffset = NUMBER(kimage_voffset);
>> >         info->max_physmem_bits = PHYS_MASK_SHIFT;
>> >         info->section_size_bits = SECTIONS_SIZE_BITS;
>> > -       info->page_offset = 0xffffffffffffffffUL << (va_bits - 1);
>> >
>> >         DEBUG_MSG("kimage_voffset   : %lx\n", kimage_voffset);
>> >         DEBUG_MSG("max_physmem_bits : %lx\n", info->max_physmem_bits);
>> > @@ -219,6 +222,48 @@ get_xen_info_arm64(void)
>> >  int
>> >  get_versiondep_info_arm64(void)
>> >  {
>> > +       unsigned long long stext;
>> > +
>> > +       /* We can read the _stext symbol from vmlinux and determine the
>> > +        * VA_BITS and page_offset.
>> > +        */
>> > +
>> > +       /* Open the vmlinux file */
>> > +       open_kernel_file();
>> > +       set_dwarf_debuginfo("vmlinux", NULL,
>> > +                       info->name_vmlinux, info->fd_vmlinux);
>> > +
>> > +       if (!get_symbol_info())
>> > +               return FALSE;
>> > +
>> > +       /* Get the '_stext' symbol */
>> > +       if (SYMBOL(_stext) == NOT_FOUND_SYMBOL) {
>> > +               ERRMSG("Can't get the symbol of _stext.\n");
>> > +               return FALSE;
>> > +       } else {
>> > +               stext = SYMBOL(_stext);
>> > +       }
>> > +
>> > +       /* Derive va_bits as per arch/arm64/Kconfig */
>> > +       if ((stext & PAGE_OFFSET_36) == PAGE_OFFSET_36) {
>> > +               va_bits = 36;
>> > +       } else if ((stext & PAGE_OFFSET_39) == PAGE_OFFSET_39) {
>> > +               va_bits = 39;
>> > +       } else if ((stext & PAGE_OFFSET_42) == PAGE_OFFSET_42) {
>> > +               va_bits = 42;
>> > +       } else if ((stext & PAGE_OFFSET_47) == PAGE_OFFSET_47) {
>> > +               va_bits = 47;
>> > +       } else if ((stext & PAGE_OFFSET_48) == PAGE_OFFSET_48) {
>> > +               va_bits = 48;
>> > +       } else {
>> > +               ERRMSG("Cannot find a proper _stext for calculating VA_BITS\n");
>> > +               return FALSE;
>> > +       }
>> > +
>> > +       info->page_offset = (0xffffffffffffffffUL) << (va_bits - 1);
>> > +
>> > +       DEBUG_MSG("page_offset=%lx, va_bits=%d\n", info->page_offset, va_bits);
>> > +
>> >         return TRUE;
>> >  }
>> >
>> > diff --git a/makedumpfile.8 b/makedumpfile.8
>> > index 15db7947d62f..be9620035316 100644
>> > --- a/makedumpfile.8
>> > +++ b/makedumpfile.8
>> > @@ -593,7 +593,7 @@ last cleared on the crashed kernel, through "dmesg --clear" for example.
>> >
>> >  .TP
>> >  \fB\-\-mem-usage\fR
>> > -This option is only for x86_64.
>> > +This option is currently supported on x86_64, arm64, ppc64 and s390x.
>> >  This option is used to show the page numbers of current system in different
>> >  use. It should be executed in 1st kernel. By the help of this, user can know
>> >  how many pages is dumpable when different dump_level is specified. It analyzes
>> > @@ -601,12 +601,19 @@ the 'System Ram' and 'kernel text' program segment of /proc/kcore excluding
>> >  the crashkernel range, then calculates the page number of different kind per
>> >  vmcoreinfo. So currently /proc/kcore need be specified explicitly.
>> >
>> > +For arm64, path to vmlinux file should be specified as well.
>> > +
>> >  .br
>> > -.B Example:
>> > +.B Example (for architectures other than arm64):
>> >  .br
>> >  # makedumpfile \-\-mem-usage /proc/kcore
>> > +
>> > +.br
>> > +.B Example (for arm64 architecture):
>> >  .br
>> >
>> > +# makedumpfile \-\-mem-usage vmlinux /proc/kcore
>> > +.br
>> >
>> >  .TP
>> >  \fB\-\-diskset=VMCORE\fR
>> > diff --git a/makedumpfile.c b/makedumpfile.c
>> > index ed138d339d9a..b38b5000aa74 100644
>> > --- a/makedumpfile.c
>> > +++ b/makedumpfile.c
>> > @@ -11090,7 +11090,14 @@ static struct option longopts[] = {
>> >         {"cyclic-buffer", required_argument, NULL, OPT_CYCLIC_BUFFER},
>> >         {"eppic", required_argument, NULL, OPT_EPPIC},
>> >         {"non-mmap", no_argument, NULL, OPT_NON_MMAP},
>> > +#ifdef __aarch64__
>> > +       /* VMLINUX file is required for aarch64 for get
>> > +        * the symbols required to calculate va_bits.
>> > +        */
>> > +       {"mem-usage", required_argument, NULL, OPT_MEM_USAGE},
>> > +#else
>> >         {"mem-usage", no_argument, NULL, OPT_MEM_USAGE},
>> > +#endif
>> >         {"splitblock-size", required_argument, NULL, OPT_SPLITBLOCK_SIZE},
>> >         {"work-dir", required_argument, NULL, OPT_WORKING_DIR},
>> >         {"num-threads", required_argument, NULL, OPT_NUM_THREADS},
>> > @@ -11201,8 +11208,22 @@ main(int argc, char *argv[])
>> >                         info->flag_partial_dmesg = 1;
>> >                         break;
>> >                 case OPT_MEM_USAGE:
>> > -                      info->flag_mem_usage = 1;
>> > -                      break;
>> > +                       info->flag_mem_usage = 1;
>> > +#ifdef __aarch64__
>> > +                       /* VMLINUX file is required for aarch64 for get
>> > +                        * the symbols required to calculate va_bits and
>> > +                        * it should be the 1st command parameter being
>> > +                        * specified.
>> > +                        */
>> > +                       if (strcmp(optarg, "/proc/kcore") == 0) {
>> > +                               MSG("vmlinux path should be 1st commandline parameter with --mem-usage option.\n");
>> > +                               goto out;
>> > +                       }
>> > +                       else {
>> > +                               info->name_vmlinux = optarg;
>> > +                       }
>> > +#endif
>> > +                       break;
>> >                 case OPT_COMPRESS_SNAPPY:
>> >                         info->flag_compress = DUMP_DH_COMPRESSED_SNAPPY;
>> >                         break;
>> > diff --git a/makedumpfile.h b/makedumpfile.h
>> > index 01eece231475..f65d91870b73 100644
>> > --- a/makedumpfile.h
>> > +++ b/makedumpfile.h
>> > @@ -2308,6 +2308,7 @@ struct elf_prstatus {
>> >  /*
>> >   * Function Prototype.
>> >   */
>> > +int open_kernel_file(void);
>> >  mdf_pfn_t get_num_dumpable_cyclic(void);
>> >  mdf_pfn_t get_num_dumpable_cyclic_withsplit(void);
>> >  int get_loads_dumpfile_cyclic(void);
>> > --
>> > 2.7.4
>> >
>
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