[PATCH V7] makedumpfile: exclude page structures of non-dumped pages
Atsushi Kumagai
ats-kumagai at wm.jp.nec.com
Tue Oct 27 21:38:24 PDT 2015
Hello Cliff,
>From: Cliff Wickman <cpw at sgi.com>
>
>Applies to the development branch as of 10/13/2015.
>Incorporates review 10/22 by kumagai-atsushi.
>Incorporates review 10/26 by kumagai-atsushi. (arch x86_64-only implementation)
Thanks for your great work.
I don't want to delay v1.5.9 release anymore, I'll merge this patch
into v1.6.0.
Thanks,
Atsushi Kumagai.
>This patch adds a -e option to makedumpfile.
>The -e option excludes kernel pages that contain nothing but kernel page
>structures for pages that are not being included in the dump.
>The -e option only works in non-cyclic mode, which its use implies.
>And only applies to the x86_64 architecture.
>
>The -e requires the use of --work-dir, as it will create a pfn file in that
>work directory. The --work-dir should probably be set up by the distro procedures
>which determine the mount point of the root device.
>This patch formerly applied after patch:
> [PATCH V2] makedumpfile: make --work-dir easier to use
>but now it stands alone.
>
>I have tested on large memory systems to demonstrate the importance
>of this feature to such systems. See some numbers below.
>
>The most dramatic demonstration was on a 32TB system where the patch
>reduced the process from 2 hours to 26 minutes. The size of the dump
>would probably have been over 30GB (but I ran out of disk space). It was
>reduced to 5.4GB.
>
>A page structure (56 bytes) exists for every 4096-byte page.
>This amounts to 3.67 million pages, or about 14GB, per terabyte of system memory!
>
>Without -e an idle 2-terabyte system can be dumped (compressed) to a file of
>about 3.6G.
>With -e that is reduced to about 456M. And the time and space savings
>multiply for each additional terabyte of memory in the system.
>
>Experimental time/size results: (basically idle systems)
>
>Memory Size With -e Without -e
> (sec.) (sec.)
>(using a sles11sp3 kernel that does not provide mmap of /proc/vmcore:)
>1TB 52 244M 257 1.7G
>2TB 128 456M 526 3.6G
>8TB 780 1.6G 3400 13.8G
>16TB 2600 3.1G 9800 (extrapolated, 2:40 is too long to wait)
>(using a sles11sp3 kernel that provides mmap of /proc/vmcore:)
>16TB 900 3.8G not done
>32TB 6000 5.4G not done
>(using a sles11sp3 kernel that provides mmap of /proc/vmcore:)
>32TB 1600 5.4G 7300 (extrapolated)
> (ran out of 19G space before 1/2 done)
>
>The only disadvantage is that various options of the crash 'kmem' command (that
>walk lists of page structures) will not work.
>Version 7.0.9 of crash is already patched to issue a warning about such commands
>when the dump is flagged DUMP_DH_EXCLUDED_VMEMMAP.
>
>
>Sorry that this patch is large. The vmemmap page scan is done by some very large
>functions, and they are all interrelated. I didn't see any point to breaking
>them into several inter-dependent patches.
>
>---
> arch/x86_64.c | 307 +++++++++++++++++++++++++++++++++++++++++++++++
> diskdump_mod.h | 1
> makedumpfile.c | 365 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> makedumpfile.h | 66 ++++++++++
> print_info.c | 10 +
> 5 files changed, 746 insertions(+), 3 deletions(-)
>
>Index: code/print_info.c
>===================================================================
>--- code.orig/print_info.c
>+++ code/print_info.c
>@@ -58,7 +58,7 @@ print_usage(void)
> MSG("\n");
> MSG("Usage:\n");
> MSG(" Creating DUMPFILE:\n");
>- MSG(" # makedumpfile [-c|-l|-p|-E] [-d DL] [-x VMLINUX|-i VMCOREINFO] VMCORE\n");
>+ MSG(" # makedumpfile [-c|-l|-p|-E] [-d DL] [-e] [-x VMLINUX|-i VMCOREINFO] VMCORE\n");
> MSG(" DUMPFILE\n");
> MSG("\n");
> MSG(" Creating DUMPFILE with filtered kernel data specified through filter config\n");
>@@ -113,6 +113,14 @@ print_usage(void)
> MSG(" -E option, because the ELF format does not support compressed data.\n");
> MSG(" THIS IS ONLY FOR THE CRASH UTILITY.\n");
> MSG("\n");
>+ MSG(" [-e]:\n");
>+ MSG(" Exclude the page structures (vmemmap) which represent excluded pages.\n");
>+ MSG(" This greatly shortens the dump of a very large memory system.\n");
>+ MSG(" The --work-dir option must also be specified, as it will be used\n");
>+ MSG(" to hold bitmaps and a file of page numbers that are to be excluded.\n");
>+ MSG(" The -e option will cause a noncyclic dump procedure.\n");
>+ MSG(" This option is only for x86_64.\n");
>+ MSG("\n");
> MSG(" [-d DL]:\n");
> MSG(" Specify the type of unnecessary page for analysis.\n");
> MSG(" Pages of the specified type are not copied to DUMPFILE. The page type\n");
>Index: code/makedumpfile.h
>===================================================================
>--- code.orig/makedumpfile.h
>+++ code/makedumpfile.h
>@@ -45,6 +45,9 @@
> #include "sadump_mod.h"
> #include <pthread.h>
>
>+#define VMEMMAPSTART 0xffffea0000000000UL
>+#define BITS_PER_WORD 64
>+
> /*
> * Result of command
> */
>@@ -496,6 +499,7 @@ do { \
> #define VMALLOC_END (info->vmalloc_end)
> #define VMEMMAP_START (info->vmemmap_start)
> #define VMEMMAP_END (info->vmemmap_end)
>+#define PMASK (0x7ffffffffffff000UL)
>
> #ifdef __aarch64__
> #define CONFIG_ARM64_PGTABLE_LEVELS 2
>@@ -609,15 +613,20 @@ do { \
> #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
> #define PGDIR_MASK (~(PGDIR_SIZE - 1))
> #define PTRS_PER_PGD (512)
>+#define PGD_SHIFT (39)
>+#define PUD_SHIFT (30)
> #define PMD_SHIFT (21)
> #define PMD_SIZE (1UL << PMD_SHIFT)
> #define PMD_MASK (~(PMD_SIZE - 1))
>+#define PTRS_PER_PUD (512)
> #define PTRS_PER_PMD (512)
> #define PTRS_PER_PTE (512)
> #define PTE_SHIFT (12)
>
> #define pml4_index(address) (((address) >> PML4_SHIFT) & (PTRS_PER_PML4 - 1))
> #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
>+#define pgd4_index(address) (((address) >> PGD_SHIFT) & (PTRS_PER_PGD - 1))
>+#define pud_index(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
> #define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
> #define pte_index(address) (((address) >> PTE_SHIFT) & (PTRS_PER_PTE - 1))
>
>@@ -783,7 +792,6 @@ do { \
> /*
> * 4 Levels paging
> */
>-#define PUD_SHIFT (PMD_SHIFT + PTRS_PER_PTD_SHIFT)
> #define PGDIR_SHIFT_4L (PUD_SHIFT + PTRS_PER_PTD_SHIFT)
>
> #define MASK_PUD ((1UL << REGION_SHIFT) - 1) & (~((1UL << PUD_SHIFT) - 1))
>@@ -802,6 +810,7 @@ do { \
> */
> static inline int stub_true() { return TRUE; }
> static inline int stub_true_ul(unsigned long x) { return TRUE; }
>+static inline int stub_false() { return FALSE; }
> #ifdef __aarch64__
> int get_phys_base_arm64(void);
> int get_machdep_info_arm64(void);
>@@ -809,6 +818,7 @@ unsigned long long vaddr_to_paddr_arm64(
> int get_versiondep_info_arm64(void);
> int get_xen_basic_info_arm64(void);
> int get_xen_info_arm64(void);
>+#define find_vmemmap() stub_false()
> #define vaddr_to_paddr(X) vaddr_to_paddr_arm64(X)
> #define get_phys_base() get_phys_base_arm64()
> #define get_machdep_info() get_machdep_info_arm64()
>@@ -822,6 +832,7 @@ int get_xen_info_arm64(void);
> int get_phys_base_arm(void);
> int get_machdep_info_arm(void);
> unsigned long long vaddr_to_paddr_arm(unsigned long vaddr);
>+#define find_vmemmap() stub_false()
> #define get_phys_base() get_phys_base_arm()
> #define get_machdep_info() get_machdep_info_arm()
> #define get_versiondep_info() stub_true()
>@@ -833,6 +844,7 @@ unsigned long long vaddr_to_paddr_arm(un
> int get_machdep_info_x86(void);
> int get_versiondep_info_x86(void);
> unsigned long long vaddr_to_paddr_x86(unsigned long vaddr);
>+#define find_vmemmap() stub_false()
> #define get_phys_base() stub_true()
> #define get_machdep_info() get_machdep_info_x86()
> #define get_versiondep_info() get_versiondep_info_x86()
>@@ -846,6 +858,7 @@ int get_phys_base_x86_64(void);
> int get_machdep_info_x86_64(void);
> int get_versiondep_info_x86_64(void);
> unsigned long long vaddr_to_paddr_x86_64(unsigned long vaddr);
>+#define find_vmemmap() find_vmemmap_x86_64()
> #define get_phys_base() get_phys_base_x86_64()
> #define get_machdep_info() get_machdep_info_x86_64()
> #define get_versiondep_info() get_versiondep_info_x86_64()
>@@ -857,6 +870,7 @@ unsigned long long vaddr_to_paddr_x86_64
> int get_machdep_info_ppc64(void);
> int get_versiondep_info_ppc64(void);
> unsigned long long vaddr_to_paddr_ppc64(unsigned long vaddr);
>+#define find_vmemmap() stub_false()
> #define get_phys_base() stub_true()
> #define get_machdep_info() get_machdep_info_ppc64()
> #define get_versiondep_info() get_versiondep_info_ppc64()
>@@ -867,6 +881,7 @@ unsigned long long vaddr_to_paddr_ppc64(
> #ifdef __powerpc32__ /* powerpc32 */
> int get_machdep_info_ppc(void);
> unsigned long long vaddr_to_paddr_ppc(unsigned long vaddr);
>+#define find_vmemmap() stub_false()
> #define get_phys_base() stub_true()
> #define get_machdep_info() get_machdep_info_ppc()
> #define get_versiondep_info() stub_true()
>@@ -878,6 +893,7 @@ unsigned long long vaddr_to_paddr_ppc(un
> int get_machdep_info_s390x(void);
> unsigned long long vaddr_to_paddr_s390x(unsigned long vaddr);
> int is_iomem_phys_addr_s390x(unsigned long addr);
>+#define find_vmemmap() stub_false()
> #define get_phys_base() stub_true()
> #define get_machdep_info() get_machdep_info_s390x()
> #define get_versiondep_info() stub_true()
>@@ -889,6 +905,7 @@ int is_iomem_phys_addr_s390x(unsigned lo
> int get_phys_base_ia64(void);
> int get_machdep_info_ia64(void);
> unsigned long long vaddr_to_paddr_ia64(unsigned long vaddr);
>+#define find_vmemmap() stub_false()
> #define get_machdep_info() get_machdep_info_ia64()
> #define get_phys_base() get_phys_base_ia64()
> #define get_versiondep_info() stub_true()
>@@ -1095,6 +1112,7 @@ struct DumpInfo {
> int flag_use_printk_log; /* did we read printk_log symbol name? */
> int flag_nospace; /* the flag of "No space on device" error */
> int flag_vmemmap; /* kernel supports vmemmap address space */
>+ int flag_excludevm; /* -e - excluding unused vmemmap pages */
> unsigned long vaddr_for_vtop; /* virtual address for debugging */
> long page_size; /* size of page */
> long page_shift;
>@@ -1686,6 +1704,51 @@ struct srcfile_table {
> char pud_t[LEN_SRCFILE];
> };
>
>+/*
>+ * This structure records where the vmemmap page structures reside, and which
>+ * pfn's are represented by those page structures.
>+ * The actual pages containing the page structures are 2MB pages, so their pfn's
>+ * will all be multiples of 0x200.
>+ * The page structures are 7 64-bit words in length (0x38) so they overlap the
>+ * 2MB boundaries. Each page structure represents a 4k page.
>+ * A 4k page is here defined to be represented on a 2MB page if its page structure
>+ * 'ends' on that page (even if it began on the page before).
>+ */
>+struct vmap_pfns {
>+ struct vmap_pfns *next;
>+ struct vmap_pfns *prev;
>+ /*
>+ * These (start/end) are literal pfns of 2MB pages on which the page
>+ * structures reside, not start and end+1.
>+ */
>+ unsigned long vmap_pfn_start;
>+ unsigned long vmap_pfn_end;
>+ /*
>+ * These (start/end) are literal pfns represented on these pages, not
>+ * start and end+1.
>+ * The starting page struct is at least partly on the first page; the
>+ * ending page struct is entirely on the last page.
>+ */
>+ unsigned long rep_pfn_start;
>+ unsigned long rep_pfn_end;
>+};
>+
>+/* for saving a list of pfns to a buffer, and then to a file if necessary */
>+struct save_control {
>+ int sc_fd;
>+ char *sc_filename;
>+ char *sc_buf;
>+ long sc_buflen; /* length of buffer never changes */
>+ long sc_bufposition; /* offset of next slot for write, or next to be read */
>+ long sc_filelen; /* length of valid data written */
>+ long sc_fileposition; /* offset in file of next entry to be read */
>+};
>+/* one entry in the buffer and file */
>+struct sc_entry {
>+ unsigned long startpfn;
>+ unsigned long numpfns;
>+};
>+
> extern struct symbol_table symbol_table;
> extern struct size_table size_table;
> extern struct offset_table offset_table;
>@@ -2011,6 +2074,7 @@ struct elf_prstatus {
> #define OPT_DEBUG 'D'
> #define OPT_DUMP_LEVEL 'd'
> #define OPT_ELF_DUMPFILE 'E'
>+#define OPT_EXCLUDE_UNUSED_VM 'e'
> #define OPT_FLATTEN 'F'
> #define OPT_FORCE 'f'
> #define OPT_GENERATE_VMCOREINFO 'g'
>Index: code/makedumpfile.c
>===================================================================
>--- code.orig/makedumpfile.c
>+++ code/makedumpfile.c
>@@ -32,10 +32,14 @@ struct offset_table offset_table;
> struct array_table array_table;
> struct number_table number_table;
> struct srcfile_table srcfile_table;
>+struct save_control sc;
>
> struct vm_table vt = { 0 };
> struct DumpInfo *info = NULL;
> struct SplitBlock *splitblock = NULL;
>+struct vmap_pfns *gvmem_pfns;
>+int nr_gvmem_pfns;
>+extern int find_vmemmap();
>
> char filename_stdout[] = FILENAME_STDOUT;
>
>@@ -5736,6 +5740,329 @@ copy_bitmap(void)
> }
> }
>
>+/*
>+ * Initialize the structure for saving pfn's to be deleted.
>+ */
>+int
>+init_save_control()
>+{
>+ int flags;
>+ char *filename;
>+
>+ filename = malloc(50);
>+ *filename = '\0';
>+ strcpy(filename, info->working_dir);
>+ strcat(filename, "/");
>+ strcat(filename, "makedumpfilepfns");
>+ sc.sc_filename = filename;
>+ flags = O_RDWR|O_CREAT|O_TRUNC;
>+ if ((sc.sc_fd = open(sc.sc_filename, flags, S_IRUSR|S_IWUSR)) < 0) {
>+ ERRMSG("Can't open the pfn file %s.\n", sc.sc_filename);
>+ return FAILED;
>+ }
>+ unlink(sc.sc_filename);
>+
>+ sc.sc_buf = malloc(info->page_size);
>+ if (!sc.sc_buf) {
>+ ERRMSG("Can't allocate a page for pfn buf.\n");
>+ return FAILED;
>+ }
>+ sc.sc_buflen = info->page_size;
>+ sc.sc_bufposition = 0;
>+ sc.sc_fileposition = 0;
>+ sc.sc_filelen = 0;
>+ return COMPLETED;
>+}
>+
>+/*
>+ * Save a starting pfn and number of pfns for later delete from bitmap.
>+ */
>+int
>+save_deletes(unsigned long startpfn, unsigned long numpfns)
>+{
>+ int i;
>+ struct sc_entry *scp;
>+
>+ if (sc.sc_bufposition == sc.sc_buflen) {
>+ i = write(sc.sc_fd, sc.sc_buf, sc.sc_buflen);
>+ if (i != sc.sc_buflen) {
>+ ERRMSG("save: Can't write a page to %s\n",
>+ sc.sc_filename);
>+ return FAILED;
>+ }
>+ sc.sc_filelen += sc.sc_buflen;
>+ sc.sc_bufposition = 0;
>+ }
>+ scp = (struct sc_entry *)(sc.sc_buf + sc.sc_bufposition);
>+ scp->startpfn = startpfn;
>+ scp->numpfns = numpfns;
>+ sc.sc_bufposition += sizeof(struct sc_entry);
>+ return COMPLETED;
>+}
>+
>+/*
>+ * Get a starting pfn and number of pfns for delete from bitmap.
>+ * Return 0 for success, 1 for 'no more'
>+ */
>+int
>+get_deletes(unsigned long *startpfn, unsigned long *numpfns)
>+{
>+ int i;
>+ struct sc_entry *scp;
>+
>+ if (sc.sc_fileposition >= sc.sc_filelen) {
>+ return FAILED;
>+ }
>+
>+ if (sc.sc_bufposition == sc.sc_buflen) {
>+ i = read(sc.sc_fd, sc.sc_buf, sc.sc_buflen);
>+ if (i <= 0) {
>+ ERRMSG("Can't read a page from %s.\n", sc.sc_filename);
>+ return FAILED;
>+ }
>+ sc.sc_bufposition = 0;
>+ }
>+ scp = (struct sc_entry *)(sc.sc_buf + sc.sc_bufposition);
>+ *startpfn = scp->startpfn;
>+ *numpfns = scp->numpfns;
>+ sc.sc_bufposition += sizeof(struct sc_entry);
>+ sc.sc_fileposition += sizeof(struct sc_entry);
>+ return COMPLETED;
>+}
>+
>+/*
>+ * Given a range of unused pfn's, check whether we can drop the vmemmap pages
>+ * that represent them.
>+ * (pfn ranges are literally start and end, not start and end+1)
>+ * see the array of vmemmap pfns and the pfns they represent: gvmem_pfns
>+ * Return COMPLETED for delete, FAILED for not to delete.
>+ */
>+int
>+find_vmemmap_pages(unsigned long startpfn, unsigned long endpfn, unsigned long *vmappfn,
>+ unsigned long *nmapnpfns)
>+{
>+ int i;
>+ long npfns_offset, vmemmap_offset, vmemmap_pfns, start_vmemmap_pfn;
>+ long npages, end_vmemmap_pfn;
>+ struct vmap_pfns *vmapp;
>+ int pagesize = info->page_size;
>+
>+ for (i = 0; i < nr_gvmem_pfns; i++) {
>+ vmapp = gvmem_pfns + i;
>+ if ((startpfn >= vmapp->rep_pfn_start) &&
>+ (endpfn <= vmapp->rep_pfn_end)) {
>+ npfns_offset = startpfn - vmapp->rep_pfn_start;
>+ vmemmap_offset = npfns_offset * size_table.page;
>+ // round up to a page boundary
>+ if (vmemmap_offset % pagesize)
>+ vmemmap_offset += (pagesize - (vmemmap_offset % pagesize));
>+ vmemmap_pfns = vmemmap_offset / pagesize;
>+ start_vmemmap_pfn = vmapp->vmap_pfn_start + vmemmap_pfns;
>+ *vmappfn = start_vmemmap_pfn;
>+
>+ npfns_offset = endpfn - vmapp->rep_pfn_start;
>+ vmemmap_offset = npfns_offset * size_table.page;
>+ // round down to page boundary
>+ vmemmap_offset -= (vmemmap_offset % pagesize);
>+ vmemmap_pfns = vmemmap_offset / pagesize;
>+ end_vmemmap_pfn = vmapp->vmap_pfn_start + vmemmap_pfns;
>+ npages = end_vmemmap_pfn - start_vmemmap_pfn;
>+ if (npages == 0)
>+ return FAILED;
>+ *nmapnpfns = npages;
>+ return COMPLETED;
>+ }
>+ }
>+ return FAILED;
>+}
>+
>+/*
>+ * Find the big holes in bitmap2; they represent ranges for which
>+ * we do not need page structures.
>+ * Bitmap1 is a map of dumpable (i.e existing) pages.
>+ * They must only be pages that exist, so they will be 0 bits
>+ * in the 2nd bitmap but 1 bits in the 1st bitmap.
>+ * For speed, only worry about whole words full of bits.
>+ */
>+int
>+find_unused_vmemmap_pages(void)
>+{
>+ struct dump_bitmap *bitmap1 = info->bitmap1;
>+ struct dump_bitmap *bitmap2 = info->bitmap2;
>+ unsigned long long pfn;
>+ unsigned long *lp1, *lp2, startpfn, endpfn;
>+ unsigned long vmapstartpfn, vmapnumpfns;
>+ int i, sz, numpages=0, did_deletes;
>+ int startword, numwords, do_break=0;
>+ long deleted_pages = 0;
>+ off_t new_offset1, new_offset2;
>+
>+ /* read each block of both bitmaps */
>+ for (pfn = 0; pfn < info->max_mapnr; pfn += PFN_BUFBITMAP) { /* size in bits */
>+ numpages++;
>+ did_deletes = 0;
>+ new_offset1 = bitmap1->offset + BUFSIZE_BITMAP * (pfn / PFN_BUFBITMAP);
>+ if (lseek(bitmap1->fd, new_offset1, SEEK_SET) < 0 ) {
>+ ERRMSG("Can't seek the bitmap(%s). %s\n",
>+ bitmap1->file_name, strerror(errno));
>+ return FAILED;
>+ }
>+ if (read(bitmap1->fd, bitmap1->buf, BUFSIZE_BITMAP) != BUFSIZE_BITMAP) {
>+ ERRMSG("Can't read the bitmap(%s). %s\n",
>+ bitmap1->file_name, strerror(errno));
>+ return FAILED;
>+ }
>+ bitmap1->no_block = pfn / PFN_BUFBITMAP;
>+
>+ new_offset2 = bitmap2->offset + BUFSIZE_BITMAP * (pfn / PFN_BUFBITMAP);
>+ if (lseek(bitmap2->fd, new_offset2, SEEK_SET) < 0 ) {
>+ ERRMSG("Can't seek the bitmap(%s). %s\n",
>+ bitmap2->file_name, strerror(errno));
>+ return FAILED;
>+ }
>+ if (read(bitmap2->fd, bitmap2->buf, BUFSIZE_BITMAP) != BUFSIZE_BITMAP) {
>+ ERRMSG("Can't read the bitmap(%s). %s\n",
>+ bitmap2->file_name, strerror(errno));
>+ return FAILED;
>+ }
>+ bitmap2->no_block = pfn / PFN_BUFBITMAP;
>+
>+ /* process this one page of both bitmaps at a time */
>+ lp1 = (unsigned long *)bitmap1->buf;
>+ lp2 = (unsigned long *)bitmap2->buf;
>+ /* sz is words in the block */
>+ sz = BUFSIZE_BITMAP / sizeof(unsigned long);
>+ startword = -1;
>+ for (i = 0; i < sz; i++, lp1++, lp2++) {
>+ /* for each whole word in the block */
>+ /* deal in full 64-page chunks only */
>+ if (*lp1 == 0xffffffffffffffffUL) {
>+ if (*lp2 == 0) {
>+ /* we are in a series we want */
>+ if (startword == -1) {
>+ /* starting a new group */
>+ startword = i;
>+ }
>+ } else {
>+ /* we hit a used page */
>+ if (startword >= 0)
>+ do_break = 1;
>+ }
>+ } else {
>+ /* we hit a hole in real memory, or part of one */
>+ if (startword >= 0)
>+ do_break = 1;
>+ }
>+ if (do_break) {
>+ do_break = 0;
>+ if (startword >= 0) {
>+ numwords = i - startword;
>+ /* 64 bits represents 64 page structs, which
>+ are not even one page of them (takes
>+ at least 73) */
>+ if (numwords > 1) {
>+ startpfn = pfn +
>+ (startword * BITS_PER_WORD);
>+ /* pfn ranges are literally start and end,
>+ not start and end + 1 */
>+ endpfn = startpfn +
>+ (numwords * BITS_PER_WORD) - 1;
>+ if (find_vmemmap_pages(startpfn, endpfn,
>+ &vmapstartpfn, &vmapnumpfns) ==
>+ COMPLETED) {
>+ if (save_deletes(vmapstartpfn,
>+ vmapnumpfns) == FAILED) {
>+ ERRMSG("save_deletes failed\n");
>+ return FAILED;
>+ }
>+ deleted_pages += vmapnumpfns;
>+ did_deletes = 1;
>+ }
>+ }
>+ }
>+ startword = -1;
>+ }
>+ }
>+ if (startword >= 0) {
>+ numwords = i - startword;
>+ if (numwords > 1) {
>+ startpfn = pfn + (startword * BITS_PER_WORD);
>+ /* pfn ranges are literally start and end,
>+ not start and end + 1 */
>+ endpfn = startpfn + (numwords * BITS_PER_WORD) - 1;
>+ if (find_vmemmap_pages(startpfn, endpfn,
>+ &vmapstartpfn, &vmapnumpfns) == COMPLETED) {
>+ if (save_deletes(vmapstartpfn, vmapnumpfns)
>+ == FAILED) {
>+ ERRMSG("save_deletes failed\n");
>+ return FAILED;
>+ }
>+ deleted_pages += vmapnumpfns;
>+ did_deletes = 1;
>+ }
>+ }
>+ }
>+ }
>+ PROGRESS_MSG("\nExcluded %ld unused vmemmap pages\n", deleted_pages);
>+
>+ return COMPLETED;
>+}
>+
>+/*
>+ * Retrieve the list of pfn's and delete them from bitmap2;
>+ */
>+void
>+delete_unused_vmemmap_pages(void)
>+{
>+ unsigned long startpfn, numpfns, pfn, i;
>+
>+ while (get_deletes(&startpfn, &numpfns) == COMPLETED) {
>+ for (i = 0, pfn = startpfn; i < numpfns; i++, pfn++) {
>+ clear_bit_on_2nd_bitmap_for_kernel(pfn, (struct cycle *)0);
>+ // note that this is never to be used in cyclic mode!
>+ }
>+ }
>+ return;
>+}
>+
>+/*
>+ * Finalize the structure for saving pfn's to be deleted.
>+ */
>+void
>+finalize_save_control()
>+{
>+ free(sc.sc_buf);
>+ close(sc.sc_fd);
>+ return;
>+}
>+
>+/*
>+ * Reset the structure for saving pfn's to be deleted so that it can be read
>+ */
>+int
>+reset_save_control()
>+{
>+ int i;
>+ if (sc.sc_bufposition == 0)
>+ return COMPLETED;
>+
>+ i = write(sc.sc_fd, sc.sc_buf, sc.sc_buflen);
>+ if (i != sc.sc_buflen) {
>+ ERRMSG("reset: Can't write a page to %s\n",
>+ sc.sc_filename);
>+ return FAILED;
>+ }
>+ sc.sc_filelen += sc.sc_bufposition;
>+
>+ if (lseek(sc.sc_fd, 0, SEEK_SET) < 0) {
>+ ERRMSG("Can't seek the pfn file %s).", sc.sc_filename);
>+ return FAILED;
>+ }
>+ sc.sc_fileposition = 0;
>+ sc.sc_bufposition = sc.sc_buflen; /* trigger 1st read */
>+ return COMPLETED;
>+}
>+
> int
> create_2nd_bitmap(struct cycle *cycle)
> {
>@@ -5815,6 +6142,20 @@ create_2nd_bitmap(struct cycle *cycle)
> if (!sync_2nd_bitmap())
> return FALSE;
>
>+ /* --exclude-unused-vm means exclude vmemmap page structures for unused pages */
>+ if (info->flag_excludevm) {
>+ if (init_save_control() == FAILED)
>+ return FALSE;
>+ if (find_unused_vmemmap_pages() == FAILED)
>+ return FALSE;
>+ if (reset_save_control() == FAILED)
>+ return FALSE;
>+ delete_unused_vmemmap_pages();
>+ finalize_save_control();
>+ if (!sync_2nd_bitmap())
>+ return FALSE;
>+ }
>+
> return TRUE;
> }
>
>@@ -6231,6 +6572,10 @@ write_kdump_header(void)
> dh->bitmap_blocks = divideup(info->len_bitmap, dh->block_size);
> memcpy(&dh->timestamp, &info->timestamp, sizeof(dh->timestamp));
> memcpy(&dh->utsname, &info->system_utsname, sizeof(dh->utsname));
>+
>+ if (info->flag_excludevm)
>+ dh->status |= DUMP_DH_EXCLUDED_VMEMMAP;
>+
> if (info->flag_compress & DUMP_DH_COMPRESSED_ZLIB)
> dh->status |= DUMP_DH_COMPRESSED_ZLIB;
> #ifdef USELZO
>@@ -9198,6 +9543,14 @@ create_dumpfile(void)
> if (!initial())
> return FALSE;
>
>+ /* create an array of translations from pfn to vmemmap pages */
>+ if (info->flag_excludevm) {
>+ if (find_vmemmap() == FAILED) {
>+ ERRMSG("Can't find vmemmap pages\n");
>+ info->flag_excludevm = 0;
>+ }
>+ }
>+
> print_vtop();
>
> num_retry = 0;
>@@ -10418,7 +10771,7 @@ main(int argc, char *argv[])
>
> info->block_order = DEFAULT_ORDER;
> message_level = DEFAULT_MSG_LEVEL;
>- while ((opt = getopt_long(argc, argv, "b:cDd:EFfg:hi:lpRvXx:", longopts,
>+ while ((opt = getopt_long(argc, argv, "b:cDd:eEFfg:hi:lpRvXx:", longopts,
> NULL)) != -1) {
> switch (opt) {
> case OPT_BLOCK_ORDER:
>@@ -10462,6 +10815,10 @@ main(int argc, char *argv[])
> info->flag_read_vmcoreinfo = 1;
> info->name_vmcoreinfo = optarg;
> break;
>+ case OPT_EXCLUDE_UNUSED_VM:
>+ info->flag_excludevm = 1; /* exclude unused vmemmap pages */
>+ info->flag_cyclic = FALSE; /* force create_2nd_bitmap */
>+ break;
> case OPT_DISKSET:
> if (!sadump_add_diskset_info(optarg))
> goto out;
>@@ -10540,6 +10897,12 @@ main(int argc, char *argv[])
> if (flag_debug)
> message_level |= ML_PRINT_DEBUG_MSG;
>
>+ if (info->flag_excludevm && !info->working_dir) {
>+ ERRMSG("Error: -%c requires --work-dir\n", OPT_EXCLUDE_UNUSED_VM);
>+ ERRMSG("Try `makedumpfile --help' for more information\n");
>+ return COMPLETED;
>+ }
>+
> if (info->flag_show_usage) {
> print_usage();
> return COMPLETED;
>Index: code/diskdump_mod.h
>===================================================================
>--- code.orig/diskdump_mod.h
>+++ code/diskdump_mod.h
>@@ -97,6 +97,7 @@ struct kdump_sub_header {
> /* paged is compressed with snappy */
> #define DUMP_DH_COMPRESSED_INCOMPLETE 0x8
> /* indicate an incomplete dumpfile */
>+#define DUMP_DH_EXCLUDED_VMEMMAP 0x10 /* unused vmemmap pages are excluded */
>
> /* descriptor of each page for vmcore */
> typedef struct page_desc {
>Index: code/arch/x86_64.c
>===================================================================
>--- code.orig/arch/x86_64.c
>+++ code/arch/x86_64.c
>@@ -18,6 +18,8 @@
> #include "../print_info.h"
> #include "../elf_info.h"
> #include "../makedumpfile.h"
>+extern struct vmap_pfns *gvmem_pfns;
>+extern int nr_gvmem_pfns;
>
> int
> is_vmalloc_addr_x86_64(ulong vaddr)
>@@ -460,5 +462,310 @@ int get_xen_info_x86_64(void)
> return TRUE;
> }
>
>+/*
>+ * Scan the kernel page table for the pfn's of the page structs
>+ * Place them in array gvmem_pfns[nr_gvmem_pfns]
>+ */
>+int
>+find_vmemmap_x86_64()
>+{
>+ int i;
>+ int pgd_index, pud_index;
>+ int start_range = 1;
>+ int num_pmds=0, num_pmds_valid=0;
>+ int break_in_valids, break_after_invalids;
>+ int do_break, done = 0;
>+ int last_valid=0, last_invalid=0;
>+ int pagestructsize, structsperhpage, hugepagesize;
>+ long page_structs_per_pud;
>+ long num_puds, groups = 0;
>+ long pgdindex, pudindex, pmdindex;
>+ long vaddr, vaddr_base;
>+ long rep_pfn_start = 0, rep_pfn_end = 0;
>+ unsigned long init_level4_pgt;
>+ unsigned long max_paddr, high_pfn;
>+ unsigned long pgd_addr, pud_addr, pmd_addr;
>+ unsigned long *pgdp, *pudp, *pmdp;
>+ unsigned long pud_page[PTRS_PER_PUD];
>+ unsigned long pmd_page[PTRS_PER_PMD];
>+ unsigned long vmap_offset_start = 0, vmap_offset_end = 0;
>+ unsigned long pmd, tpfn;
>+ unsigned long pvaddr = 0;
>+ unsigned long data_addr = 0, last_data_addr = 0, start_data_addr = 0;
>+ /*
>+ * data_addr is the paddr of the page holding the page structs.
>+ * We keep lists of contiguous pages and the pfn's that their
>+ * page structs represent.
>+ * start_data_addr and last_data_addr mark start/end of those
>+ * contiguous areas.
>+ * An area descriptor is vmap start/end pfn and rep start/end
>+ * of the pfn's represented by the vmap start/end.
>+ */
>+ struct vmap_pfns *vmapp, *vmaphead = NULL, *cur, *tail;
>+
>+ init_level4_pgt = SYMBOL(init_level4_pgt);
>+ if (init_level4_pgt == NOT_FOUND_SYMBOL) {
>+ ERRMSG("init_level4_pgt not found\n");
>+ return FAILED;
>+ }
>+ pagestructsize = size_table.page;
>+ hugepagesize = PTRS_PER_PMD * info->page_size;
>+ vaddr_base = info->vmemmap_start;
>+ vaddr = vaddr_base;
>+ max_paddr = get_max_paddr();
>+ /*
>+ * the page structures are mapped at VMEMMAP_START (info->vmemmap_start)
>+ * for max_paddr >> 12 page structures
>+ */
>+ high_pfn = max_paddr >> 12;
>+ pgd_index = pgd4_index(vaddr_base);
>+ pud_index = pud_index(vaddr_base);
>+ pgd_addr = vaddr_to_paddr(init_level4_pgt); /* address of pgd */
>+ pgd_addr += pgd_index * sizeof(unsigned long);
>+ page_structs_per_pud = (PTRS_PER_PUD * PTRS_PER_PMD * info->page_size) /
>+ pagestructsize;
>+ num_puds = (high_pfn + page_structs_per_pud - 1) / page_structs_per_pud;
>+ pvaddr = VMEMMAP_START;
>+ structsperhpage = hugepagesize / pagestructsize;
>+
>+ /* outer loop is for pud entries in the pgd */
>+ for (pgdindex = 0, pgdp = (unsigned long *)pgd_addr; pgdindex < num_puds;
>+ pgdindex++, pgdp++) {
>+ /* read the pgd one word at a time, into pud_addr */
>+ if (!readmem(PADDR, (unsigned long long)pgdp, (void *)&pud_addr,
>+ sizeof(unsigned long))) {
>+ ERRMSG("Can't get pgd entry for slot %d.\n", pgd_index);
>+ return FAILED;
>+ }
>+ /* mask the pgd entry for the address of the pud page */
>+ pud_addr &= PMASK;
>+ /* read the entire pud page */
>+ if (!readmem(PADDR, (unsigned long long)pud_addr, (void *)pud_page,
>+ PTRS_PER_PUD * sizeof(unsigned long))) {
>+ ERRMSG("Can't get pud entry for pgd slot %ld.\n", pgdindex);
>+ return FAILED;
>+ }
>+ /* step thru each pmd address in the pud page */
>+ /* pudp points to an entry in the pud page */
>+ for (pudp = (unsigned long *)pud_page, pudindex = 0;
>+ pudindex < PTRS_PER_PUD; pudindex++, pudp++) {
>+ pmd_addr = *pudp & PMASK;
>+ /* read the entire pmd page */
>+ if (!readmem(PADDR, pmd_addr, (void *)pmd_page,
>+ PTRS_PER_PMD * sizeof(unsigned long))) {
>+ ERRMSG("Can't get pud entry for slot %ld.\n", pudindex);
>+ return FAILED;
>+ }
>+ /* pmdp points to an entry in the pmd */
>+ for (pmdp = (unsigned long *)pmd_page, pmdindex = 0;
>+ pmdindex < PTRS_PER_PMD; pmdindex++, pmdp++) {
>+ /* linear page position in this page table: */
>+ pmd = *pmdp;
>+ num_pmds++;
>+ tpfn = (pvaddr - VMEMMAP_START) /
>+ pagestructsize;
>+ if (tpfn >= high_pfn) {
>+ done = 1;
>+ break;
>+ }
>+ /*
>+ * vmap_offset_start:
>+ * Starting logical position in the
>+ * vmemmap array for the group stays
>+ * constant until a hole in the table
>+ * or a break in contiguousness.
>+ */
>+
>+ /*
>+ * Ending logical position in the
>+ * vmemmap array:
>+ */
>+ vmap_offset_end += hugepagesize;
>+ do_break = 0;
>+ break_in_valids = 0;
>+ break_after_invalids = 0;
>+ /*
>+ * We want breaks either when:
>+ * - we hit a hole (invalid)
>+ * - we discontiguous page is a string of valids
>+ */
>+ if (pmd) {
>+ data_addr = (pmd & PMASK);
>+ if (start_range) {
>+ /* first-time kludge */
>+ start_data_addr = data_addr;
>+ last_data_addr = start_data_addr
>+ - hugepagesize;
>+ start_range = 0;
>+ }
>+ if (last_invalid) {
>+ /* end of a hole */
>+ start_data_addr = data_addr;
>+ last_data_addr = start_data_addr
>+ - hugepagesize;
>+ /* trigger update of offset */
>+ do_break = 1;
>+ }
>+ last_valid = 1;
>+ last_invalid = 0;
>+ /*
>+ * we have a gap in physical
>+ * contiguousness in the table.
>+ */
>+ /* ?? consecutive holes will have
>+ same data_addr */
>+ if (data_addr !=
>+ last_data_addr + hugepagesize) {
>+ do_break = 1;
>+ break_in_valids = 1;
>+ }
>+ DEBUG_MSG("valid: pud %ld pmd %ld pfn %#lx"
>+ " pvaddr %#lx pfns %#lx-%lx"
>+ " start %#lx end %#lx\n",
>+ pudindex, pmdindex,
>+ data_addr >> 12,
>+ pvaddr, tpfn,
>+ tpfn + structsperhpage - 1,
>+ vmap_offset_start,
>+ vmap_offset_end);
>+ num_pmds_valid++;
>+ if (!(pmd & _PAGE_PSE)) {
>+ printf("vmemmap pmd not huge, abort\n");
>+ return FAILED;
>+ }
>+ } else {
>+ if (last_valid) {
>+ /* this a hole after some valids */
>+ do_break = 1;
>+ break_in_valids = 1;
>+ break_after_invalids = 0;
>+ }
>+ last_valid = 0;
>+ last_invalid = 1;
>+ /*
>+ * There are holes in this sparsely
>+ * populated table; they are 2MB gaps
>+ * represented by null pmd entries.
>+ */
>+ DEBUG_MSG("invalid: pud %ld pmd %ld %#lx"
>+ " pfns %#lx-%lx start %#lx end"
>+ " %#lx\n", pudindex, pmdindex,
>+ pvaddr, tpfn,
>+ tpfn + structsperhpage - 1,
>+ vmap_offset_start,
>+ vmap_offset_end);
>+ }
>+ if (do_break) {
>+ /* The end of a hole is not summarized.
>+ * It must be the start of a hole or
>+ * hitting a discontiguous series.
>+ */
>+ if (break_in_valids || break_after_invalids) {
>+ /*
>+ * calculate that pfns
>+ * represented by the current
>+ * offset in the vmemmap.
>+ */
>+ /* page struct even partly on this page */
>+ rep_pfn_start = vmap_offset_start /
>+ pagestructsize;
>+ /* ending page struct entirely on
>+ this page */
>+ rep_pfn_end = ((vmap_offset_end -
>+ hugepagesize) / pagestructsize);
>+ DEBUG_MSG("vmap pfns %#lx-%lx "
>+ "represent pfns %#lx-%lx\n\n",
>+ start_data_addr >> PAGESHIFT(),
>+ last_data_addr >> PAGESHIFT(),
>+ rep_pfn_start, rep_pfn_end);
>+ groups++;
>+ vmapp = (struct vmap_pfns *)malloc(
>+ sizeof(struct vmap_pfns));
>+ /* pfn of this 2MB page of page structs */
>+ vmapp->vmap_pfn_start = start_data_addr
>+ >> PTE_SHIFT;
>+ vmapp->vmap_pfn_end = last_data_addr
>+ >> PTE_SHIFT;
>+ /* these (start/end) are literal pfns
>+ * on this page, not start and end+1 */
>+ vmapp->rep_pfn_start = rep_pfn_start;
>+ vmapp->rep_pfn_end = rep_pfn_end;
>+
>+ if (!vmaphead) {
>+ vmaphead = vmapp;
>+ vmapp->next = vmapp;
>+ vmapp->prev = vmapp;
>+ } else {
>+ tail = vmaphead->prev;
>+ vmaphead->prev = vmapp;
>+ tail->next = vmapp;
>+ vmapp->next = vmaphead;
>+ vmapp->prev = tail;
>+ }
>+ }
>+
>+ /* update logical position at every break */
>+ vmap_offset_start =
>+ vmap_offset_end - hugepagesize;
>+ start_data_addr = data_addr;
>+ }
>+
>+ last_data_addr = data_addr;
>+ pvaddr += hugepagesize;
>+ /*
>+ * pvaddr is current virtual address
>+ * eg 0xffffea0004200000 if
>+ * vmap_offset_start is 4200000
>+ */
>+ }
>+ }
>+ tpfn = (pvaddr - VMEMMAP_START) / pagestructsize;
>+ if (tpfn >= high_pfn) {
>+ done = 1;
>+ break;
>+ }
>+ }
>+ rep_pfn_start = vmap_offset_start / pagestructsize;
>+ rep_pfn_end = (vmap_offset_end - hugepagesize) / pagestructsize;
>+ DEBUG_MSG("vmap pfns %#lx-%lx represent pfns %#lx-%lx\n\n",
>+ start_data_addr >> PAGESHIFT(), last_data_addr >> PAGESHIFT(),
>+ rep_pfn_start, rep_pfn_end);
>+ groups++;
>+ vmapp = (struct vmap_pfns *)malloc(sizeof(struct vmap_pfns));
>+ vmapp->vmap_pfn_start = start_data_addr >> PTE_SHIFT;
>+ vmapp->vmap_pfn_end = last_data_addr >> PTE_SHIFT;
>+ vmapp->rep_pfn_start = rep_pfn_start;
>+ vmapp->rep_pfn_end = rep_pfn_end;
>+ if (!vmaphead) {
>+ vmaphead = vmapp;
>+ vmapp->next = vmapp;
>+ vmapp->prev = vmapp;
>+ } else {
>+ tail = vmaphead->prev;
>+ vmaphead->prev = vmapp;
>+ tail->next = vmapp;
>+ vmapp->next = vmaphead;
>+ vmapp->prev = tail;
>+ }
>+ DEBUG_MSG("num_pmds: %d num_pmds_valid %d\n", num_pmds, num_pmds_valid);
>+
>+ /* transfer the linked list to an array */
>+ cur = vmaphead;
>+ gvmem_pfns = (struct vmap_pfns *)malloc(sizeof(struct vmap_pfns) * groups);
>+ i = 0;
>+ do {
>+ vmapp = gvmem_pfns + i;
>+ vmapp->vmap_pfn_start = cur->vmap_pfn_start;
>+ vmapp->vmap_pfn_end = cur->vmap_pfn_end;
>+ vmapp->rep_pfn_start = cur->rep_pfn_start;
>+ vmapp->rep_pfn_end = cur->rep_pfn_end;
>+ cur = cur->next;
>+ free(cur->prev);
>+ i++;
>+ } while (cur != vmaphead);
>+ nr_gvmem_pfns = i;
>+ return COMPLETED;
>+}
>+
> #endif /* x86_64 */
>
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