Hi Don, > -----Original Message----- > From: Don Brady <don.brady@xxxxxxxxxxx> > > ZFS caches pages for file data in its Adaptive Replacement Cache (ARC). > This cache is separate from the VFS page cache. The amount of data > cached can be significant and it would be ideal to exclude it from the > crashdump file. ZFS can tag these pages so they are easily identifiable > from within makedumpfile. > > ref https://github.com/zfsonlinux/zfs/pull/8899/files > > Below is a suggested patch that can work in tandem with the above ZFS > changes to exclude the ZFS ARC file data pages from a dump file. Thank you for the patch. The idea looks simple and good to me. >From makedumpfile's viewpoint, it would be better to be separated from the dump level (DL_EXCLUDE_CACHE_PRI) because there may be a case that we want to exclude the ZFS ARC pages only, it can exclude unexpected pages by accident, and a similar request to exclude private pages that have another tag value can happen. So what about adding a new option to specify a tag value and exclude the pages that have it? For example: # makedumpfile -l -d 1 --private-page-filter 0x2F5ABDF11ECAC4E For simplicity, it would be enough to accept only a single value, not multiple values/times for now. Thanks, Kazu > > Signed-off-by: Don Brady <don.brady@xxxxxxxxxxx> > --- > makedumpfile.c | 36 ++++++++++++++++++++++++++++++++++-- > 1 file changed, 34 insertions(+), 2 deletions(-) > > diff --git a/makedumpfile.c b/makedumpfile.c > index d76a435..b760934 100644 > --- a/makedumpfile.c > +++ b/makedumpfile.c > @@ -85,6 +85,7 @@ mdf_pfn_t pfn_zero; > mdf_pfn_t pfn_memhole; > mdf_pfn_t pfn_cache; > mdf_pfn_t pfn_cache_private; > +mdf_pfn_t pfn_zfs_arc_pages; > mdf_pfn_t pfn_user; > mdf_pfn_t pfn_free; > mdf_pfn_t pfn_hwpoison; > @@ -282,6 +283,20 @@ is_cache_page(unsigned long flags) > return FALSE; > } > > +#define ZFS_ABD_FILE_CACHE 0x2F5ABDF11ECAC4E > + > +static int > +is_zfs_cache_page(unsigned long flags, unsigned long private) > +{ > + /* > + * ZFS cached file data resides in pages with a private tag > + */ > + if (isPrivate(flags) && private == ZFS_ABD_FILE_CACHE) > + return TRUE; > + > + return FALSE; > +} > + > static inline unsigned long > calculate_len_buf_out(long page_size) > { > @@ -6048,6 +6063,13 @@ __exclude_unnecessary_pages(unsigned long mem_map, > else > pfn_counter = &pfn_cache; > } > + /* > + * Exclude ZFS ARC pages > + */ > + else if ((info->dump_level & DL_EXCLUDE_CACHE_PRI) > + && is_zfs_cache_page(flags, private)) { > + pfn_counter = &pfn_zfs_arc_pages; > + } > /* > * Exclude the data page of the user process. > * - anonymous pages > @@ -7551,6 +7573,7 @@ write_elf_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_page) > if (info->flag_cyclic) { > pfn_zero = pfn_cache = pfn_cache_private = 0; > pfn_user = pfn_free = pfn_hwpoison = pfn_offline = 0; > + pfn_zfs_arc_pages = 0; > pfn_memhole = info->max_mapnr; > } > > @@ -8833,6 +8856,7 @@ write_kdump_pages_and_bitmap_cyclic(struct cache_data *cd_header, struct cache_d > */ > pfn_zero = pfn_cache = pfn_cache_private = 0; > pfn_user = pfn_free = pfn_hwpoison = pfn_offline = 0; > + pfn_zfs_arc_pages = 0; > pfn_memhole = info->max_mapnr; > > /* > @@ -9777,7 +9801,8 @@ print_report(void) > pfn_original = info->max_mapnr - pfn_memhole; > > pfn_excluded = pfn_zero + pfn_cache + pfn_cache_private > - + pfn_user + pfn_free + pfn_hwpoison + pfn_offline; > + + pfn_user + pfn_free + pfn_hwpoison + pfn_offline > + + pfn_zfs_arc_pages; > shrinking = (pfn_original - pfn_excluded) * 100; > shrinking = shrinking / pfn_original; > > @@ -9788,6 +9813,9 @@ print_report(void) > REPORT_MSG(" Non-private cache pages : 0x%016llx\n", pfn_cache); > REPORT_MSG(" Private cache pages : 0x%016llx\n", > pfn_cache_private); > + if (pfn_zfs_arc_pages != 0) > + REPORT_MSG(" ZFS ARC file data pages : 0x%016llx\n", > + pfn_zfs_arc_pages); > REPORT_MSG(" User process data pages : 0x%016llx\n", pfn_user); > REPORT_MSG(" Free pages : 0x%016llx\n", pfn_free); > REPORT_MSG(" Hwpoison pages : 0x%016llx\n", pfn_hwpoison); > @@ -9819,7 +9847,8 @@ print_mem_usage(void) > pfn_original = info->max_mapnr - pfn_memhole; > > pfn_excluded = pfn_zero + pfn_cache + pfn_cache_private > - + pfn_user + pfn_free + pfn_hwpoison + pfn_offline; > + + pfn_user + pfn_free + pfn_hwpoison + pfn_offline > + + pfn_zfs_arc_pages; > shrinking = (pfn_original - pfn_excluded) * 100; > shrinking = shrinking / pfn_original; > total_size = info->page_size * pfn_original; > @@ -9833,6 +9862,9 @@ print_mem_usage(void) > pfn_cache); > MSG("PRI_CACHE %-16llu yes Cache pages with private flag\n", > pfn_cache_private); > + if (pfn_zfs_arc_pages != 0) > + MSG("ZFS_CACHE %-16llu yes ZFS ARC data pages\n", > + pfn_zfs_arc_pages); > MSG("USER %-16llu yes User process pages\n", pfn_user); > MSG("FREE %-16llu yes Free pages\n", pfn_free); > MSG("KERN_DATA %-16llu no Dumpable kernel data \n", > -- > 2.17.1 > > > _______________________________________________ > kexec mailing list > kexec@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/kexec _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
