[MAKDUMPFILE PATCH] Add option to estimate the size of vmcore dump files
lijiang
lijiang at redhat.com
Wed Oct 14 00:31:30 EDT 2020
在 2020年10月13日 17:27, Bhupesh Sharma 写道:
> Hello Julien,
>
> Thanks for the patch. Some nitpicks inline:
>
> On Mon, Oct 12, 2020 at 12:39 PM Julien Thierry <jthierry at redhat.com> 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.
>>
>> Signed-off-by: Julien Thierry <jthierry at redhat.com>
>> Cc: Kazuhito Hagio <k-hagio-ab at nec.com>
>> ---
>> 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.
>
>> 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.
>
>> 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);
>> } 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.
>
>> + 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
The option '--vmcore-size' will get all dumpable pages like the process of
saving vmcore, compute and return the final size of vmcore, but it doesn't
save the vmcore data.
The reason is that it doesn't affect the performance of mkdumprd, because
mkdumprd wants to use the size of vmcore to determine if there is enough
free disk space to hold the vmcore at a certain time point.
Saving vmcore data will waste time and cause the performance degradation
in this case.
Unless, provide additional option and work with the '--vmcore-size' together
in order to choose generating a dumpfile or not.
Thanks.
Lianbo
> dumpfile when --vmcore-size is specified). Maybe we need to think more
> on supporting this use-case as well.
>
> Regards,
> Bhupesh
>
>
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