Re: [Crash-utility] [PATCH 1/1 V2] crash: initial note of excluded page structures

----- Original Message ----- > > Version 2 > - Moves the warning to this point: > ... > This GDB was configured as "x86_64-unknown-linux-gnu"... > > WARNING: All unused vmemmap page structures are excluded from this > dump. > This will cause failures of the kmem command if it attempts to > walk any list of free pages (with options -f -F -i -s and -S). > > SYSTEM MAP: /boot/System.map-2.6.32-cpw > ... > > - Drop patch 2, which added warnings to individual kmem options. > > - Feel free to change the wording of the warning. > > And this patch is contingent upon the acceptance of a change to the > makedumpfile command. > http://marc.info/?l=kexec&m=138853299130125&w=2 > > > If makedumpfile excludes unused page structures it will flag that > fact in the dump header. > (There are about 3.67 million pages full of page structures for > every tera byte of system memory. The great bulk of those > page structures are not needed.) > Their exclusion is a makedumpfile option. > > Crash will display a note during initialization if such structures > have been excluded. Crash commands that walk page freelists, for > example, will fail. So the note will help the user understand why. > > Signed-off-by: Cliff Wickman <cpw(a)sgi.com&gt; > --- > defs.h | 1 + > diskdump.c | 3 +++ > diskdump.h | 1 + > main.c | 6 ++++++ > 4 files changed, 11 insertions(+) > > Index: crash-7.0.4/diskdump.c > =================================================================== > --- crash-7.0.4.orig/diskdump.c > +++ crash-7.0.4/diskdump.c > @@ -749,6 +749,9 @@ restart: > dd->valid_pages[i]++; > } > > + if (header->status & DUMP_DH_EXCLUDED_VMEMMAP) > + pc->flags2 |= VMEXCLUDED; > + > return TRUE; > > err: > Index: crash-7.0.4/diskdump.h > =================================================================== > --- crash-7.0.4.orig/diskdump.h > +++ crash-7.0.4/diskdump.h > @@ -84,6 +84,7 @@ struct kdump_sub_header { > #define DUMP_DH_COMPRESSED_ZLIB 0x1 /* page is compressed with zlib */ > #define DUMP_DH_COMPRESSED_LZO 0x2 /* page is compressed with lzo */ > #define DUMP_DH_COMPRESSED_SNAPPY 0x4 /* page is compressed with snappy > */ > +#define DUMP_DH_EXCLUDED_VMEMMAP 0x8 /* unused vmemmap pages are > excluded */ > > /* descriptor of each page for vmcore */ > typedef struct page_desc { > Index: crash-7.0.4/defs.h > =================================================================== > --- crash-7.0.4.orig/defs.h > +++ crash-7.0.4/defs.h > @@ -505,6 +505,7 @@ struct program_context { > #define VMCOREINFO (0x400ULL) > #define ALLOW_FP (0x800ULL) > #define REM_PAUSED_F (0x1000ULL) > +#define VMEXCLUDED (0x2000ULL) > #define REMOTE_PAUSED() (pc->flags2 & REM_PAUSED_F) > char *cleanup; > char *namelist_orig; > Index: crash-7.0.4/main.c > =================================================================== > --- crash-7.0.4.orig/main.c > +++ crash-7.0.4/main.c > @@ -662,6 +662,12 @@ main_loop(void) > } else > SIGACTION(SIGINT, restart, &pc->sigaction, NULL); > > + if (pc->flags2 & VMEXCLUDED) > + fprintf(fp, > + "WARNING: All unused vmemmap page structures are excluded from this dump.\n" > + " This will cause failures of the kmem command if it attempts to\n" > + " walk any list of free pages (with options -f -F -i -s and -S).\n\n"); > + > /* > * Display system statistics and current context. > */ > This patch looks reasonable. BTW, what happens if you enter "kmem <address>" alone with no option? It should fail as well, no?