From: Qiao Nuohan <qiaonuo...@cn.fujitsu.com>
Struct dump_bitmap is associated with a tmp file, and the tmp file can be used
to save data of bitmap in kdump-compressed format temporarily.
The following patch will use these functions to get the data of bitmap and cache
them into tmp files.
Signed-off-by: Qiao Nuohan <qiaonuo...@cn.fujitsu.com>
Reviewed-by: Zhang Xiaohe <zhan...@cn.fujitsu.com>
---
Makefile.target | 2 +-
dump_bitmap.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++++
include/dump_bitmap.h | 60 +++++++++++++++++
3 files changed, 232 insertions(+), 1 deletions(-)
create mode 100644 dump_bitmap.c
create mode 100644 include/dump_bitmap.h
diff --git a/Makefile.target b/Makefile.target
index ce4391f..00d4f13 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -112,7 +112,7 @@ obj-$(CONFIG_FDT) += device_tree.o
obj-$(CONFIG_KVM) += kvm-all.o
obj-y += memory.o savevm.o cputlb.o
obj-$(CONFIG_HAVE_GET_MEMORY_MAPPING) += memory_mapping.o
-obj-$(CONFIG_HAVE_CORE_DUMP) += dump.o
+obj-$(CONFIG_HAVE_CORE_DUMP) += dump.o dump_bitmap.o
obj-$(CONFIG_NO_GET_MEMORY_MAPPING) += memory_mapping-stub.o
obj-$(CONFIG_NO_CORE_DUMP) += dump-stub.o
LIBS+=$(libs_softmmu)
diff --git a/dump_bitmap.c b/dump_bitmap.c
new file mode 100644
index 0000000..d2f6c9f
--- /dev/null
+++ b/dump_bitmap.c
@@ -0,0 +1,171 @@
+/*
+ * QEMU dump bitmap
+ *
+ * Copyright Fujitsu, Corp. 2013
+ *
+ * Authors:
+ * Qiao Nuohan <qiaonuo...@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "dump_bitmap.h"
+
+int init_dump_bitmap(struct dump_bitmap *db, const char *filename)
+{
+ int fd;
+ char *tmpname;
+
+ /* init the tmp file */
+ tmpname = getenv("TMPDIR");
+ if (!tmpname) {
+ tmpname = (char *)P_tmpdir;
+ }
+
+ db->file_name = (char *)g_strdup_printf("%s/%s", tmpname, filename);
+
+ fd = mkstemp(db->file_name);
+ if (fd < 0) {
+ return -1;
+ }
+
+ db->fd = fd;
+ unlink(db->file_name);
+
+ /* num_block should be set to -1, for nothing is store in buf now */
+ db->num_block = -1;
+ memset(db->buf, 0, BUFSIZE_BITMAP);
+ /* the tmp file starts to write at the very beginning */
+ db->offset = 0;
+
+ return 0;
+}
+
+int clear_dump_bitmap(struct dump_bitmap *db, size_t len_db)
+{
+ int ret;
+ char buf[BUFSIZE_BITMAP];
+ off_t offset_bit;
+
+ /* use buf to clear the tmp file block by block */
+ memset(buf, 0, sizeof(buf));
+
+ ret = lseek(db->fd, db->offset, SEEK_SET);
+ if (ret < 0) {
+ return -1;
+ }
+
+ offset_bit = 0;
+ while (offset_bit < len_db) {
+ if (write(db->fd, buf, BUFSIZE_BITMAP) != BUFSIZE_BITMAP) {
+ return -1;
+ }
+
+ offset_bit += BUFSIZE_BITMAP;
+ }
+
+ return 0;
+}
+
+int set_dump_bitmap(struct dump_bitmap *db, unsigned long long pfn, int val)
+{
+ int byte, bit;
+ off_t old_offset, new_offset;
+ old_offset = db->offset + BUFSIZE_BITMAP * db->num_block;
+ new_offset = db->offset + BUFSIZE_BITMAP * (pfn / PFN_BUFBITMAP);
+
+ /*
+ * if the block needed to be set is not same as the one cached in buf,
+ * write the block back to the tmp file, then cache new block to the buf
+ */
+ if (0 <= db->num_block && old_offset != new_offset) {
+ if (lseek(db->fd, old_offset, SEEK_SET) < 0) {
+ return -1;
+ }
+
+ if (write(db->fd, db->buf, BUFSIZE_BITMAP) != BUFSIZE_BITMAP) {
+ return -1;
+ }
+ }
+
+ if (old_offset != new_offset) {
+ if (lseek(db->fd, new_offset, SEEK_SET) < 0) {
+ return -1;
+ }
+
+ if (read(db->fd, db->buf, BUFSIZE_BITMAP) != BUFSIZE_BITMAP) {
+ return -1;
+ }
+
+ db->num_block = pfn / PFN_BUFBITMAP;
+ }
+
+ /* get the exact place of the bit in the buf, set it */
+ byte = (pfn % PFN_BUFBITMAP) >> 3;
+ bit = (pfn % PFN_BUFBITMAP) & 7;
+ if (val) {
+ db->buf[byte] |= 1<<bit;
+ } else {
+ db->buf[byte] &= ~(1<<bit);
+ }
+
+ return 0;
+}
+
+int sync_dump_bitmap(struct dump_bitmap *db)
+{
+ off_t offset;
+ offset = db->offset + BUFSIZE_BITMAP * db->num_block;
+
+ /* db has not been used yet */
+ if (db->num_block < 0) {
+ return 0;
+ }
+
+ if (lseek(db->fd, offset, SEEK_SET) < 0) {
+ return -1;
+ }
+
+ if (write(db->fd, db->buf, BUFSIZE_BITMAP) != BUFSIZE_BITMAP) {
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * check if the bit is set to 1
+ */
+static inline int is_on(char *bitmap, int i)
+{
+ return bitmap[i>>3] & (1 << (i & 7));
+}
+
+int is_bit_set(struct dump_bitmap *db, unsigned long long pfn)
+{
+ off_t offset;
+
+ /* cache the block pfn belongs to, then check the block */
+ if (pfn == 0 || db->num_block != pfn/PFN_BUFBITMAP) {
+ offset = db->offset + BUFSIZE_BITMAP * (pfn/PFN_BUFBITMAP);
+ lseek(db->fd, offset, SEEK_SET);
+ read(db->fd, db->buf, BUFSIZE_BITMAP);
+ db->num_block = pfn/PFN_BUFBITMAP;
+ }
+
+ return is_on(db->buf, pfn%PFN_BUFBITMAP);
+}
+
+void free_dump_bitmap(struct dump_bitmap *db)
+{
+ if (db) {
+ if (db->file_name) {
+ g_free(db->file_name);
+ }
+
+ g_free(db);
+ }
+}
diff --git a/include/dump_bitmap.h b/include/dump_bitmap.h
new file mode 100644
index 0000000..ee91543
--- /dev/null
+++ b/include/dump_bitmap.h
@@ -0,0 +1,60 @@
+/*
+ * QEMU dump bitmap
+ *
+ * Copyright Fujitsu, Corp. 2013
+ *
+ * Authors:
+ * Qiao Nuohan <qiaonuo...@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef DUMP_BITMAP_H
+#define DUMP_BITMAP_H
+
+#define BUFSIZE_BITMAP (4096)
+#define PFN_BUFBITMAP (CHAR_BIT * BUFSIZE_BITMAP)
+
+struct dump_bitmap {
+ int fd; /* fd of the tmp file */
+ int num_block; /* number of blocks cached in buf */
+ char *file_name; /* name of the tmp file */
+ char buf[BUFSIZE_BITMAP]; /* used to cache blocks */
+ off_t offset; /* offset of the tmp file */
+};
+
+/*
+ * create a tmp file used to store dump bitmap, then init buf of dump_bitmap
+ */
+int init_dump_bitmap(struct dump_bitmap *db, const char *filename);
+
+/*
+ * clear the content of the tmp file with all bits set to 0
+ */
+int clear_dump_bitmap(struct dump_bitmap *db, size_t len_db);
+
+/*
+ * 'pfn' is the number of bit needed to be set, use buf to cache the block
which
+ * 'pfn' belongs to, then set 'val' to the bit
+ */
+int set_dump_bitmap(struct dump_bitmap *db, unsigned long long pfn, int val);
+
+/*
+ * when buf is caching a block, sync_dump_bitmap is needed to write the cached
+ * block to the tmp file
+ */
+int sync_dump_bitmap(struct dump_bitmap *db);
+
+/*
+ * check whether 'pfn' is set
+ */
+int is_bit_set(struct dump_bitmap *db, unsigned long long pfn);
+
+/*
+ * free the space used by dump_bitmap
+ */
+void free_dump_bitmap(struct dump_bitmap *db);
+
+#endif
--
1.7.1
