The size of cyclic buffer is set to DEFAULT_BUFSIZE_CYCLIC(1MB) when
the size isn't specified. But 1MB is too small for large memory machine
and the number of cycle will be so large. As a result, a lot of time
will be spend for dump filtering.
To resolve the issue above, I add calculate_cyclic_buffer_size() to
calculate the buffer size as needed.
Concretely, the logic is to choose the lesser value of the two below
as the size of cyclic buffer:
a. the size enough for storing the 1st/2nd bitmap for the whole of vmcore
b. 80% of free memory (as safety limit)
calculate_cyclic_buffer_size() uses max_mapnr, so it needs to be done
after get_max_mapnr().
Signed-off-by: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
---
makedumpfile.c | 70 +++++++++++++++++++++++++++++++++++++++-------------------
makedumpfile.h | 6 +----
2 files changed, 48 insertions(+), 28 deletions(-)
diff --git a/makedumpfile.c b/makedumpfile.c
index 73a466e..f784400 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -2573,29 +2573,6 @@ initial(void)
}
#endif
- if (info->flag_cyclic) {
- /*
- * buffer size is specified as Kbyte
- */
- if (info->bufsize_cyclic == 0)
- info->bufsize_cyclic = DEFAULT_BUFSIZE_CYCLIC;
- else
- info->bufsize_cyclic <<= 10;
-
- /*
- * Max buffer size is 100 MB
- */
- if (info->bufsize_cyclic > (100 << 20)) {
- MSG("Specified buffer size is too large, ");
- MSG("The buffer size for the cyclic mode will be truncated to 100 MB.\n");
- info->bufsize_cyclic = (100 << 20);
- }
- info->pfn_cyclic = info->bufsize_cyclic * BITPERBYTE;
-
- DEBUG_MSG("\n");
- DEBUG_MSG("Buffer size for the cyclic mode: %ld\n", info->bufsize_cyclic);
- }
-
if (info->flag_exclude_xen_dom) {
if(info->flag_cyclic) {
info->flag_cyclic = FALSE;
@@ -2737,6 +2714,30 @@ out:
if (!get_max_mapnr())
return FALSE;
+ if (info->flag_cyclic) {
+ /*
+ * buffer size is specified as Kbyte
+ */
+ if (info->bufsize_cyclic == 0) {
+ if (!calculate_cyclic_buffer_size())
+ return FALSE;
+ } else
+ info->bufsize_cyclic <<= 10;
+
+ /*
+ * Max buffer size is 100 MB
+ */
+ if (info->bufsize_cyclic > (100 << 20)) {
+ MSG("Specified buffer size is too large, ");
+ MSG("The buffer size for the cyclic mode will be truncated to 100 MB.\n");
+ info->bufsize_cyclic = (100 << 20);
+ }
+ info->pfn_cyclic = info->bufsize_cyclic * BITPERBYTE;
+
+ DEBUG_MSG("\n");
+ DEBUG_MSG("Buffer size for the cyclic mode: %ld\n", info->bufsize_cyclic);
+ }
+
if (debug_info) {
if (info->flag_sadump)
(void) sadump_virt_phys_base();
@@ -8006,6 +8007,29 @@ out:
return free_size;
}
+
+/*
+ * Choose the lesser value of the two below as the size of cyclic buffer.
+ * - the size enough for storing the 1st/2nd bitmap for the whole of vmcore
+ * - 80% of free memory
+ */
+int
+calculate_cyclic_buffer_size(void) {
+ unsigned long long free_size, needed_size;
+
+ if (info->max_mapnr <= 0) {
+ ERRMSG("Invalid max_mapnr(%llu).\n", info->max_mapnr);
+ return FALSE;
+ }
+
+ free_size = get_free_memory_size() * 0.8;
+ needed_size = (info->max_mapnr * 2) / BITPERBYTE;
+
+ info->bufsize_cyclic = (free_size <= needed_size) ? free_size : needed_size;
+
+ return TRUE;
+}
+
static struct option longopts[] = {
{"split", no_argument, NULL, 's'},
{"reassemble", no_argument, NULL, 'r'},
diff --git a/makedumpfile.h b/makedumpfile.h
index c91b4e9..8ffef76 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -199,11 +199,6 @@ isAnon(unsigned long mapping)
#define FILENAME_STDOUT "STDOUT"
/*
- * For cyclic processing
- */
-#define DEFAULT_BUFSIZE_CYCLIC (1024 * 1024)
-
-/*
* Minimam vmcore has 2 ProgramHeaderTables(PT_NOTE and PT_LOAD).
*/
#define MIN_ELF32_HEADER_SIZE \
@@ -1612,5 +1607,6 @@ unsigned long long get_num_dumpable_cyclic(void);
int get_loads_dumpfile_cyclic(void);
int initial_xen(void);
unsigned long long get_free_memory_size(void);
+int calculate_cyclic_buffer_size(void);
#endif /* MAKEDUMPFILE_H */
--
1.7.11
