Hi Julien,
-----Original Message-----
> Hello Julien,
>
> On Tue, Oct 13, 2020 at 3:23 PM Julien Thierry <jthierry@xxxxxxxxxx> wrote:
> >
> > Hi Bhupesh,
> >
> > On 10/13/20 10:27 AM, Bhupesh Sharma wrote:
> > > Hello Julien,
> > >
> > > Thanks for the patch. Some nitpicks inline:
> > >
> > > On Mon, Oct 12, 2020 at 12:39 PM Julien Thierry <jthierry@xxxxxxxxxx> wrote:
> > >>
> > >> A user might want to know how much space a vmcore file will take on
> > >> the system and how much space on their disk should be available to
> > >> save it during a crash.
> > >>
> > >> The option --vmcore-size does not create the vmcore file but provides
> > >> an estimation of the size of the final vmcore file created with the
> > >> same make dumpfile options.
Interesting. Do you have any actual use case? e.g. used by kdumpctl?
or use it in kdump initramfs?
> > >>
> > >> Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
> > >> Cc: Kazuhito Hagio <k-hagio-ab@xxxxxxx>
> > >> ---
> > >> makedumpfile.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++--
> > >> makedumpfile.h | 12 +++++++
> > >> print_info.c | 4 +++
> > >> 3 files changed, 111 insertions(+), 3 deletions(-)
> > >
> > > Please update 'makedumpfile.8' as well in v2, so that the man page can
> > > document the newly added option and how to use it to determine the
> > > vmcore-size.
> > >
> >
> > Ah yes, I'll do that.
> >
> > >> diff --git a/makedumpfile.c b/makedumpfile.c
> > >> index 4c4251e..0a2bfba 100644
> > >> --- a/makedumpfile.c
> > >> +++ b/makedumpfile.c
> > >> @@ -26,6 +26,7 @@
> > >> #include <limits.h>
> > >> #include <assert.h>
> > >> #include <zlib.h>
> > >> +#include <libgen.h>
> > >
> > > I know we don't follow alphabetical order for include files in
> > > makedumpfile code, but it would be good to place the new - ones
> > > accordingly. So <libgen.h> can go with <limits.h> here.
> > >
> >
> > Noted.
> >
> > >> struct symbol_table symbol_table;
> > >> struct size_table size_table;
> > >> @@ -1366,7 +1367,25 @@ open_dump_file(void)
> > >> if (!info->flag_force)
> > >> open_flags |= O_EXCL;
> > >>
> > >> - if (info->flag_flatten) {
> > >> + if (info->flag_vmcore_size) {
> > >> + char *namecpy;
> > >> + struct stat statbuf;
> > >> + int res;
> > >> +
> > >> + namecpy = strdup(info->name_dumpfile ?
> > >> + info->name_dumpfile : ".");
> > >> +
> > >> + res = stat(dirname(namecpy), &statbuf);
> > >> + free(namecpy);
> > >> + if (res != 0)
> > >> + return FALSE;
> > >> +
> > >> + fd = -1;
> > >> + info->dumpsize_info.blksize = statbuf.st_blksize;
> > >> + info->dumpsize_info.block_buff_size = BASE_NUM_BLOCKS;
> > >> + info->dumpsize_info.block_info = calloc(BASE_NUM_BLOCKS, 1);
> > >> + info->dumpsize_info.non_hole_blocks = 0;
> > >> + } else if (info->flag_flatten) {
> > >> fd = STDOUT_FILENO;
> > >> info->name_dumpfile = filename_stdout;
> > >> } else if ((fd = open(info->name_dumpfile, open_flags,
> > >> @@ -1384,6 +1403,9 @@ check_dump_file(const char *path)
> > >> {
> > >> char *err_str;
> > >>
> > >> + if (info->flag_vmcore_size)
> > >> + return TRUE;
> > >> +
> > >> if (access(path, F_OK) != 0)
> > >> return TRUE; /* File does not exist */
> > >> if (info->flag_force) {
> > >> @@ -4622,6 +4644,47 @@ write_and_check_space(int fd, void *buf, size_t buf_size, char *file_name)
> > >> return TRUE;
> > >> }
> > >>
> > >> +static int
> > >> +write_buffer_update_size_info(off_t offset, void *buf, size_t buf_size)
> > >> +{
> > >> + struct dumpsize_info *dumpsize_info = &info->dumpsize_info;
> > >> + int blk_end_idx = (offset + buf_size - 1) / dumpsize_info->blksize;
> > >> + int i;
> > >> +
> > >> + /* Need to grow the dumpsize block buffer? */
> > >> + if (blk_end_idx >= dumpsize_info->block_buff_size) {
> > >> + int alloc_size = MAX(blk_end_idx - dumpsize_info->block_buff_size, BASE_NUM_BLOCKS);
> > >> +
> > >> + dumpsize_info->block_info = realloc(dumpsize_info->block_info,
> > >> + dumpsize_info->block_buff_size + alloc_size);
> > >> + if (!dumpsize_info->block_info) {
> > >> + ERRMSG("Not enough memory\n");
> > >> + return FALSE;
> > >> + }
> > >> +
> > >> + memset(dumpsize_info->block_info + dumpsize_info->block_buff_size,
> > >> + 0, alloc_size);
> > >> + dumpsize_info->block_buff_size += alloc_size;
> > >> + }
> > >> +
> > >> + for (i = 0; i < buf_size; ++i) {
> > >> + int blk_idx = (offset + i) / dumpsize_info->blksize;
> > >> +
> > >> + if (dumpsize_info->block_info[blk_idx]) {
> > >> + i += dumpsize_info->blksize;
> > >> + i = i - (i % dumpsize_info->blksize) - 1;
> > >> + continue;
> > >> + }
> > >> +
> > >> + if (((char *) buf)[i] != 0) {
> > >> + dumpsize_info->non_hole_blocks++;
> > >> + dumpsize_info->block_info[blk_idx] = 1;
> > >> + }
> > >> + }
> > >> +
> > >> + return TRUE;
> > >> +}
> > >> +
> > >> int
> > >> write_buffer(int fd, off_t offset, void *buf, size_t buf_size, char *file_name)
> > >> {
> > >> @@ -4643,6 +4706,8 @@ write_buffer(int fd, off_t offset, void *buf, size_t buf_size, char *file_name)
> > >> }
> > >> if (!write_and_check_space(fd, &fdh, sizeof(fdh), file_name))
> > >> return FALSE;
> > >> + } else if (info->flag_vmcore_size && fd == info->fd_dumpfile) {
> > >> + return write_buffer_update_size_info(offset, buf, buf_size);
Why do we need this function? makedumpfile actually writes zero-filled
pages to the dumpfile with -d 0, and doesn't write them with -d 1.
So isn't "write_bytes += buf_size" enough? For example, with -d 30,
# makedumpfile --vmcore-size -d30 vmcore
Estimated size to save vmcore is: 147595264 Bytes
write_bytes: 172782736 Bytes // calculated by "write_bytes += buf_size"
makedumpfile Completed.
# makedumpfile -d30 vmcore dump.d30
Copying data : [100.0 %] / eta: 0s
The dumpfile is saved to dump.d30.
makedumpfile Completed.
# ls -ls dump.d30
168740 -rw------- 1 root root 172787864 Oct 16 15:14 dump.d30
> > >> } else {
> > >> if (lseek(fd, offset, SEEK_SET) == failed) {
> > >> ERRMSG("Can't seek the dump file(%s). %s\n",
> > >> @@ -9018,6 +9083,12 @@ close_dump_file(void)
> > >> if (info->flag_flatten)
> > >> return;
> > >>
> > >> + if (info->flag_vmcore_size && info->fd_dumpfile == -1) {
> > >> + free(info->dumpsize_info.block_info);
> > >> + info->dumpsize_info.block_info = NULL;
> > >> + return;
> > >> + }
> > >> +
> > >> if (close(info->fd_dumpfile) < 0)
> > >> ERRMSG("Can't close the dump file(%s). %s\n",
> > >> info->name_dumpfile, strerror(errno));
> > >> @@ -10963,6 +11034,12 @@ check_param_for_creating_dumpfile(int argc, char *argv[])
> > >> if (info->flag_flatten && info->flag_split)
> > >> return FALSE;
> > >>
> > >> + if (info->flag_flatten && info->flag_vmcore_size)
> > >> + return FALSE;
> > >> +
> > >> + if (info->flag_mem_usage && info->flag_vmcore_size)
> > >> + return FALSE;
> > >> +
> > >> if (info->name_filterconfig && !info->name_vmlinux)
> > >> return FALSE;
> > >>
> > >> @@ -11043,7 +11120,8 @@ check_param_for_creating_dumpfile(int argc, char *argv[])
> > >> */
> > >> info->name_memory = argv[optind];
> > >>
> > >> - } else if ((argc == optind + 1) && info->flag_mem_usage) {
> > >> + } else if ((argc == optind + 1) && (info->flag_mem_usage ||
> > >> + info->flag_vmcore_size)) {
> > >> /*
> > >> * Parameter for showing the page number of memory
> > >> * in different use from.
> > >> @@ -11423,6 +11501,7 @@ static struct option longopts[] = {
> > >> {"work-dir", required_argument, NULL, OPT_WORKING_DIR},
> > >> {"num-threads", required_argument, NULL, OPT_NUM_THREADS},
> > >> {"check-params", no_argument, NULL, OPT_CHECK_PARAMS},
> > >> + {"vmcore-size", no_argument, NULL, OPT_VMCORE_SIZE},
> > >> {0, 0, 0, 0}
> > >> };
> > >>
> > >> @@ -11589,6 +11668,9 @@ main(int argc, char *argv[])
> > >> info->flag_check_params = TRUE;
> > >> message_level = DEFAULT_MSG_LEVEL;
> > >> break;
> > >> + case OPT_VMCORE_SIZE:
> > >> + info->flag_vmcore_size = TRUE;
> > >> + break;
> > >> case '?':
> > >> MSG("Commandline parameter is invalid.\n");
> > >> MSG("Try `makedumpfile --help' for more information.\n");
> > >> @@ -11598,6 +11680,10 @@ main(int argc, char *argv[])
> > >> if (flag_debug)
> > >> message_level |= ML_PRINT_DEBUG_MSG;
> > >>
> > >> + if (info->flag_vmcore_size)
> > >> + /* Suppress progress indicator as dumpfile won't get written */
> > >> + message_level &= ~ML_PRINT_PROGRESS;
> > >> +
> > >> if (info->flag_check_params)
> > >> /* suppress debugging messages */
> > >> message_level = DEFAULT_MSG_LEVEL;
> > >> @@ -11751,7 +11837,11 @@ main(int argc, char *argv[])
> > >> goto out;
> > >>
> > >> MSG("\n");
> > >> - if (info->flag_split) {
> > >> +
> > >> + if (info->flag_vmcore_size) {
> > >> + MSG("Estimated size to save vmcore is: %lld Bytes\n",
> > >> + (long long)info->dumpsize_info.non_hole_blocks *
> info->dumpsize_info.blksize);
> > >> + } else if (info->flag_split) {
> > >> MSG("The dumpfiles are saved to ");
> > >> for (i = 0; i < info->num_dumpfile; i++) {
> > >> if (i != (info->num_dumpfile - 1))
> > >> @@ -11808,6 +11898,8 @@ out:
> > >> free(info->page_buf);
> > >> if (info->parallel_info != NULL)
> > >> free(info->parallel_info);
> > >> + if (info->dumpsize_info.block_info != NULL)
> > >> + free(info->dumpsize_info.block_info);
> > >> free(info);
> > >>
> > >> if (splitblock) {
> > >> diff --git a/makedumpfile.h b/makedumpfile.h
> > >> index 03fb4ce..fd78d5f 100644
> > >> --- a/makedumpfile.h
> > >> +++ b/makedumpfile.h
> > >> @@ -1277,6 +1277,15 @@ struct parallel_info {
> > >> #endif
> > >> };
> > >>
> > >> +#define BASE_NUM_BLOCKS 50
> > >> +
> > >> +struct dumpsize_info {
> > >> + int blksize;
> > >> + int block_buff_size;
> > >> + unsigned char *block_info;
> > >> + int non_hole_blocks;
> > >> +};
> > >> +
> > >> struct ppc64_vmemmap {
> > >> unsigned long phys;
> > >> unsigned long virt;
> > >> @@ -1321,6 +1330,7 @@ struct DumpInfo {
> > >> int flag_vmemmap; /* kernel supports vmemmap address space */
> > >> int flag_excludevm; /* -e - excluding unused vmemmap pages */
> > >> int flag_use_count; /* _refcount is named _count in struct page */
> > >> + int flag_vmcore_size; /* estimate the size of the vmcore file instead of
> creating it */
> > >> unsigned long vaddr_for_vtop; /* virtual address for debugging */
> > >> long page_size; /* size of page */
> > >> long page_shift;
> > >> @@ -1425,6 +1435,7 @@ struct DumpInfo {
> > >> int num_dumpfile;
> > >> struct splitting_info *splitting_info;
> > >> struct parallel_info *parallel_info;
> > >> + struct dumpsize_info dumpsize_info;
> > >>
> > >> /*
> > >> * bitmap info:
> > >> @@ -2364,6 +2375,7 @@ struct elf_prstatus {
> > >> #define OPT_NUM_THREADS OPT_START+16
> > >> #define OPT_PARTIAL_DMESG OPT_START+17
> > >> #define OPT_CHECK_PARAMS OPT_START+18
> > >> +#define OPT_VMCORE_SIZE OPT_START+19
> > >>
> > >> /*
> > >> * Function Prototype.
> > >> diff --git a/print_info.c b/print_info.c
> > >> index e0c38b4..6f5a165 100644
> > >> --- a/print_info.c
> > >> +++ b/print_info.c
> > >> @@ -308,6 +308,10 @@ print_usage(void)
> > >> MSG(" the crashkernel range, then calculates the page number of different kind per\n");
> > >> MSG(" vmcoreinfo. So currently /proc/kcore need be specified explicitly.\n");
> > >> MSG("\n");
> > >> + MSG(" [--vmcore-size]:\n");
> > >> + MSG(" This option provides an estimation of the size needed to save VMCORE on disk.\n");
> > >> + MSG(" This option option cannot be used in combination with -F.\n");
> > >
> > > Also not in combination with --mem-usage (as per the code changes above)?
> > > And may be the options '--mem-usage / -F' also need an update to
> > > mention they can't be used with --vmcore-size option.
> > >
> >
> > Good point, I'll update those.
> >
> > >> + MSG("\n");
> > >> MSG(" [-D]:\n");
> > >> MSG(" Print debugging message.\n");
> > >> MSG("\n");
> > >> --
> > >
> > > I like the idea, but sometimes we use makedumpfile to generate a
> > > dumpfile in the primary kernel as well. For example:
> > >
> > > $ makedumpfile -d 31 -x vmlinux /proc/kcore dumpfile
> > >
> > > In such use-cases it is useful to use --vmcore-size and still generate
> > > the dumpfile (right now the default behaviour is not to generate a
> > > dumpfile when --vmcore-size is specified). Maybe we need to think more
> > > on supporting this use-case as well.
> > >
> >
> > The thing is, if you are generating the dumpfile, you can just check the
> > size of the file created with "du -b" or some other command.
>
> I agree, but I just was looking to replace the two 'makedumpfile +
> du' steps with a single 'makedumpfile --vmcore-size' step.
>
> > Overall I don't mind supporting your case as well. Maybe that can depend
> > on whether a vmcore/dumpfile filename is provided:
> >
> > $ makedumpfile -d 31 -x vmlinux /proc/kcore # only estimates the size
> >
> > $ makedumpfile -d 31 -x vmlinux /proc/kcore dumpfile # writes the
> > dumpfile and gives the final size
> >
> > Any thought, opinions, suggestions?
>
> Let's wait for Kazu's opinion on the same, but I am ok with using a
> two-step 'makedumpfile + du' approach for now (and later expand
> --vmcore-size as we encounter more use-cases).
>
> @Kazuhito Hagio : What's your opinion on the above?
I would prefer only estimating with the option.
And if the write_bytes method above is usable, it can be shown also
in report messages when wrote the dumpfile.
Thanks,
Kazu
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