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. 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
