On 09/11/14 at 08:52am, Atsushi Kumagai wrote:
> >Hi Atsushi,
> >
> >Since huge pages are included in user pages, I can't think of a way to
> >make test cases for huge page exclusion. Could you give some suggestions
> >on this or how did you test it?
>
> Before I posted this patch, I tested as below.
> This idea came from the fact that old makedumpfile can't exclude
> huge pages except the first page(PG_head).
>
> 1. Get the number of hugepages from /proc/meminfo
> 2. Calculate the number of PG_tail pages
> 3. Capture the dumpfile without filtering
> 4. Run makedumpfile and compare the report message between v1.5.6
> and v1.5.7(rc) to get how many user pages become excludable with
> this patch.
> 5. The result of Step2's and Step4's must be same, confirm it.
>
> The way above is for THP but you can apply it also for hugetlbfs
> if you take care of the things that old makedumpfile can't exclude
> *any* hugetlbfs pages.
But THP is also Anonymous pages, doesn't it do the same for THP between
1.5.6 and 1.5.7?
>
> I recommend to separate the two cases completely by enabling either
> THP or hugetlbfs explicitly since it's easier to confirm the results.
For hugeTlbfs, this works, I will try this.
>
>
> Thanks
> Atsushi Kumagai
>
> >
> >Thanks
> >Baoquan
> >
> >
> >On 08/20/14 at 07:27am, Atsushi Kumagai wrote:
> >> There are 2 types of hugepages in the kernel, the both should be
> >> excluded as user pages.
> >>
> >> 1. Transparent huge pages (THP)
> >> All the pages are anonymous pages (at least for now), so we should
> >> just get how many pages are in the corresponding hugepage.
> >> It can be gotten from the page->lru.prev of the second page in the
> >> hugepage.
> >>
> >> 2. Hugetlbfs pages
> >> The pages aren't anonymous pages but kind of user pages, we should
> >> exclude also these pages in any way.
> >> Luckily, it's possible to detect these pages by looking the
> >> page->lru.next of the second page in the hugepage. This idea came
> >> from the kernel's PageHuge().
> >> The number of pages can be gotten in the same way as THP.
> >>
> >> Changelog:
> >> v4:
> >> - Cleaned up according to Petr's and Baoquan's comments.
> >> v3:
> >> - Cleaned up according to Petr's comments.
> >> - Fix misdetection of hugetlb pages.
> >> v2:
> >> - Rebased to "Generic multi-page exclusion".
> >>
> >> Signed-off-by: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
> >> ---
> >> makedumpfile.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++----------
> >> makedumpfile.h | 7 +++++
> >> 2 files changed, 78 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/makedumpfile.c b/makedumpfile.c
> >> index 11cd473..b4b6eca 100644
> >> --- a/makedumpfile.c
> >> +++ b/makedumpfile.c
> >> @@ -1180,6 +1180,7 @@ get_symbol_info(void)
> >> SYMBOL_INIT(vmemmap_list, "vmemmap_list");
> >> SYMBOL_INIT(mmu_psize_defs, "mmu_psize_defs");
> >> SYMBOL_INIT(mmu_vmemmap_psize, "mmu_vmemmap_psize");
> >> + SYMBOL_INIT(free_huge_page, "free_huge_page");
> >>
> >> SYMBOL_INIT(cpu_pgd, "cpu_pgd");
> >> SYMBOL_INIT(demote_segment_4k, "demote_segment_4k");
> >> @@ -1296,6 +1297,15 @@ get_structure_info(void)
> >> ENUM_NUMBER_INIT(PG_slab, "PG_slab");
> >> ENUM_NUMBER_INIT(PG_hwpoison, "PG_hwpoison");
> >>
> >> + ENUM_NUMBER_INIT(PG_head_mask, "PG_head_mask");
> >> + if (NUMBER(PG_head_mask) == NOT_FOUND_NUMBER) {
> >> + ENUM_NUMBER_INIT(PG_head, "PG_head");
> >> + if (NUMBER(PG_head) == NOT_FOUND_NUMBER)
> >> + ENUM_NUMBER_INIT(PG_head, "PG_compound");
> >> + if (NUMBER(PG_head) != NOT_FOUND_NUMBER)
> >> + NUMBER(PG_head_mask) = 1UL << NUMBER(PG_head);
> >> + }
> >> +
> >> ENUM_TYPE_SIZE_INIT(pageflags, "pageflags");
> >>
> >> TYPEDEF_SIZE_INIT(nodemask_t, "nodemask_t");
> >> @@ -1530,6 +1540,9 @@ get_value_for_old_linux(void)
> >> NUMBER(PG_swapcache) = PG_swapcache_ORIGINAL;
> >> if (NUMBER(PG_slab) == NOT_FOUND_NUMBER)
> >> NUMBER(PG_slab) = PG_slab_ORIGINAL;
> >> + if (NUMBER(PG_head_mask) == NOT_FOUND_NUMBER)
> >> + NUMBER(PG_head_mask) = 1L << PG_compound_ORIGINAL;
> >> +
> >> /*
> >> * The values from here are for free page filtering based on
> >> * mem_map array. These are minimum effort to cover old
> >> @@ -1699,6 +1712,7 @@ write_vmcoreinfo_data(void)
> >> WRITE_SYMBOL("mmu_vmemmap_psize", mmu_vmemmap_psize);
> >> WRITE_SYMBOL("cpu_pgd", cpu_pgd);
> >> WRITE_SYMBOL("demote_segment_4k", demote_segment_4k);
> >> + WRITE_SYMBOL("free_huge_page", free_huge_page);
> >>
> >> /*
> >> * write the structure size of 1st kernel
> >> @@ -1788,6 +1802,7 @@ write_vmcoreinfo_data(void)
> >>
> >> WRITE_NUMBER("PG_lru", PG_lru);
> >> WRITE_NUMBER("PG_private", PG_private);
> >> + WRITE_NUMBER("PG_head_mask", PG_head_mask);
> >> WRITE_NUMBER("PG_swapcache", PG_swapcache);
> >> WRITE_NUMBER("PG_buddy", PG_buddy);
> >> WRITE_NUMBER("PG_slab", PG_slab);
> >> @@ -2040,6 +2055,7 @@ read_vmcoreinfo(void)
> >> READ_SYMBOL("mmu_vmemmap_psize", mmu_vmemmap_psize);
> >> READ_SYMBOL("cpu_pgd", cpu_pgd);
> >> READ_SYMBOL("demote_segment_4k", demote_segment_4k);
> >> + READ_SYMBOL("free_huge_page", free_huge_page);
> >>
> >> READ_STRUCTURE_SIZE("page", page);
> >> READ_STRUCTURE_SIZE("mem_section", mem_section);
> >> @@ -2116,6 +2132,7 @@ read_vmcoreinfo(void)
> >>
> >> READ_NUMBER("PG_lru", PG_lru);
> >> READ_NUMBER("PG_private", PG_private);
> >> + READ_NUMBER("PG_head_mask", PG_head_mask);
> >> READ_NUMBER("PG_swapcache", PG_swapcache);
> >> READ_NUMBER("PG_slab", PG_slab);
> >> READ_NUMBER("PG_buddy", PG_buddy);
> >> @@ -4643,13 +4660,16 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> >> mdf_pfn_t pfn_start, mdf_pfn_t pfn_end, struct cycle *cycle)
> >> {
> >> mdf_pfn_t pfn;
> >> + mdf_pfn_t *pfn_counter;
> >> + mdf_pfn_t nr_pages;
> >> unsigned long index_pg, pfn_mm;
> >> unsigned long long maddr;
> >> mdf_pfn_t pfn_read_start, pfn_read_end;
> >> unsigned char page_cache[SIZE(page) * PGMM_CACHED];
> >> unsigned char *pcache;
> >> - unsigned int _count, _mapcount = 0;
> >> + unsigned int _count, _mapcount = 0, compound_order = 0;
> >> unsigned long flags, mapping, private = 0;
> >> + unsigned long compound_dtor;
> >>
> >> /*
> >> * If a multi-page exclusion is pending, do it first
> >> @@ -4715,11 +4735,36 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> >> flags = ULONG(pcache + OFFSET(page.flags));
> >> _count = UINT(pcache + OFFSET(page._count));
> >> mapping = ULONG(pcache + OFFSET(page.mapping));
> >> +
> >> + if ((index_pg < PGMM_CACHED - 1) &&
> >> + isCompoundHead(flags)) {
> >> + compound_order = ULONG(pcache + SIZE(page) + OFFSET(page.lru)
> >> + + OFFSET(list_head.prev));
> >> + compound_dtor = ULONG(pcache + SIZE(page) + OFFSET(page.lru)
> >> + + OFFSET(list_head.next));
> >> +
> >> + if ((compound_order >= sizeof(unsigned long) * 8)
> >> + || ((pfn & ((1UL << compound_order) - 1)) != 0)) {
> >> + /* Invalid order */
> >> + compound_order = 0;
> >> + }
> >> + } else {
> >> + /*
> >> + * The last pfn of the mem_map cache must not be compound page
> >> + * since all compound pages are aligned to its page order and
> >> + * PGMM_CACHED is a power of 2.
> >> + */
> >> + compound_order = 0;
> >> + compound_dtor = 0;
> >> + }
> >> +
> >> if (OFFSET(page._mapcount) != NOT_FOUND_STRUCTURE)
> >> _mapcount = UINT(pcache + OFFSET(page._mapcount));
> >> if (OFFSET(page.private) != NOT_FOUND_STRUCTURE)
> >> private = ULONG(pcache + OFFSET(page.private));
> >>
> >> + nr_pages = 1 << compound_order;
> >> + pfn_counter = NULL;
> >> /*
> >> * Exclude the free page managed by a buddy
> >> * Use buddy identification of free pages whether cyclic or not.
> >> @@ -4727,12 +4772,8 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> >> if ((info->dump_level & DL_EXCLUDE_FREE)
> >> && info->page_is_buddy
> >> && info->page_is_buddy(flags, _mapcount, private, _count)) {
> >> - int nr_pages = 1 << private;
> >> -
> >> - exclude_range(&pfn_free, pfn, pfn + nr_pages, cycle);
> >> -
> >> - pfn += nr_pages - 1;
> >> - mem_map += (nr_pages - 1) * SIZE(page);
> >> + nr_pages = 1 << private;
> >> + pfn_counter = &pfn_free;
> >> }
> >> /*
> >> * Exclude the cache page without the private page.
> >> @@ -4740,8 +4781,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> >> else if ((info->dump_level & DL_EXCLUDE_CACHE)
> >> && (isLRU(flags) || isSwapCache(flags))
> >> && !isPrivate(flags) && !isAnon(mapping)) {
> >> - if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
> >> - pfn_cache++;
> >> + pfn_counter = &pfn_cache;
> >> }
> >> /*
> >> * Exclude the cache page with the private page.
> >> @@ -4749,23 +4789,39 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> >> else if ((info->dump_level & DL_EXCLUDE_CACHE_PRI)
> >> && (isLRU(flags) || isSwapCache(flags))
> >> && !isAnon(mapping)) {
> >> - if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
> >> - pfn_cache_private++;
> >> + pfn_counter = &pfn_cache_private;
> >> }
> >> /*
> >> * Exclude the data page of the user process.
> >> + * - anonymous pages
> >> + * - hugetlbfs pages
> >> */
> >> else if ((info->dump_level & DL_EXCLUDE_USER_DATA)
> >> - && isAnon(mapping)) {
> >> - if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
> >> - pfn_user++;
> >> + && (isAnon(mapping) || isHugetlb(compound_dtor))) {
> >> + pfn_counter = &pfn_user;
> >> }
> >> /*
> >> * Exclude the hwpoison page.
> >> */
> >> else if (isHWPOISON(flags)) {
> >> + pfn_counter = &pfn_hwpoison;
> >> + }
> >> + /*
> >> + * Unexcludable page
> >> + */
> >> + else
> >> + continue;
> >> +
> >> + /*
> >> + * Execute exclusion
> >> + */
> >> + if (nr_pages == 1) {
> >> if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
> >> - pfn_hwpoison++;
> >> + (*pfn_counter)++;
> >> + } else {
> >> + exclude_range(pfn_counter, pfn, pfn + nr_pages, cycle);
> >> + pfn += nr_pages - 1;
> >> + mem_map += (nr_pages - 1) * SIZE(page);
> >> }
> >> }
> >> return TRUE;
> >> diff --git a/makedumpfile.h b/makedumpfile.h
> >> index eba9798..9f90b53 100644
> >> --- a/makedumpfile.h
> >> +++ b/makedumpfile.h
> >> @@ -74,6 +74,7 @@ int get_mem_type(void);
> >> #define PG_lru_ORIGINAL (5)
> >> #define PG_slab_ORIGINAL (7)
> >> #define PG_private_ORIGINAL (11) /* Has something at ->private */
> >> +#define PG_compound_ORIGINAL (14) /* Is part of a compound page */
> >> #define PG_swapcache_ORIGINAL (15) /* Swap page: swp_entry_t in private */
> >>
> >> #define PAGE_BUDDY_MAPCOUNT_VALUE_v2_6_38 (-2)
> >> @@ -148,6 +149,9 @@ test_bit(int nr, unsigned long addr)
> >>
> >> #define isLRU(flags) test_bit(NUMBER(PG_lru), flags)
> >> #define isPrivate(flags) test_bit(NUMBER(PG_private), flags)
> >> +#define isCompoundHead(flags) (!!((flags) & NUMBER(PG_head_mask)))
> >> +#define isHugetlb(dtor) ((SYMBOL(free_huge_page) != NOT_FOUND_SYMBOL) \
> >> + && (SYMBOL(free_huge_page) == dtor))
> >> #define isSwapCache(flags) test_bit(NUMBER(PG_swapcache), flags)
> >> #define isHWPOISON(flags) (test_bit(NUMBER(PG_hwpoison), flags) \
> >> && (NUMBER(PG_hwpoison) != NOT_FOUND_NUMBER))
> >> @@ -1218,6 +1222,7 @@ struct symbol_table {
> >> unsigned long long node_remap_start_vaddr;
> >> unsigned long long node_remap_end_vaddr;
> >> unsigned long long node_remap_start_pfn;
> >> + unsigned long long free_huge_page;
> >>
> >> /*
> >> * for Xen extraction
> >> @@ -1509,6 +1514,8 @@ struct number_table {
> >> */
> >> long PG_lru;
> >> long PG_private;
> >> + long PG_head;
> >> + long PG_head_mask;
> >> long PG_swapcache;
> >> long PG_buddy;
> >> long PG_slab;
> >> --
> >> 1.9.0
> >>
> >> _______________________________________________
> >> kexec mailing list
> >> kexec at lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/kexec
