# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1252309078 -3600
# Node ID 49b561416efca3b5ebe143ce6349f892f249b5f4
# Parent ead107bc25cb18143213d271b4122bf87d790228
Fix some issues for HVM log dirty:
* Add necessary logging dirty in qemu to avoid guest error with
intensive disk access when live migration
* Take place of shared memory between qemu and migration tools by new
added hypercall, which is clean and simple
Signed-Off-By: Zhai, Edwin <edwin.zhai@xxxxxxxxx>
---
tools/libxc/ia64/xc_ia64_linux_save.c | 38 +--------
tools/libxc/xc_domain_save.c | 41 +---------
tools/libxc/xenguest.h | 3
tools/xcutils/xc_save.c | 133 ++++++++++------------------------
4 files changed, 53 insertions(+), 162 deletions(-)
diff -r ead107bc25cb -r 49b561416efc tools/libxc/ia64/xc_ia64_linux_save.c
--- a/tools/libxc/ia64/xc_ia64_linux_save.c Fri Sep 04 08:43:05 2009 +0100
+++ b/tools/libxc/ia64/xc_ia64_linux_save.c Mon Sep 07 08:37:58 2009 +0100
@@ -382,8 +382,7 @@ int
int
xc_domain_save(int xc_handle, int io_fd, uint32_t dom, uint32_t max_iters,
uint32_t max_factor, uint32_t flags, int (*suspend)(void),
- int hvm, void *(*init_qemu_maps)(int, unsigned),
- void (*qemu_flip_buffer)(int, int))
+ int hvm, void (*switch_qemu_logdirty)(int, unsigned))
{
DECLARE_DOMCTL;
xc_dominfo_t info;
@@ -423,11 +422,6 @@ xc_domain_save(int xc_handle, int io_fd,
unsigned long *to_skip = NULL;
char *mem;
-
- /* HVM: shared-memory bitmaps for getting log-dirty bits from qemu-dm */
- unsigned long *qemu_bitmaps[2];
- int qemu_active = 0;
- int qemu_non_active = 1;
/* for foreign p2m exposure */
unsigned long memmap_info_num_pages;
@@ -545,14 +539,9 @@ xc_domain_save(int xc_handle, int io_fd,
goto out;
}
- if (hvm) {
- /* Get qemu-dm logging dirty pages too */
- void *seg = init_qemu_maps(dom, bitmap_size);
- qemu_bitmaps[0] = seg;
- qemu_bitmaps[1] = seg + bitmap_size;
- qemu_active = 0;
- qemu_non_active = 1;
- }
+ /* Enable qemu-dm logging dirty pages to xen */
+ if (hvm)
+ switch_qemu_logdirty(dom, 1);
} else {
/* This is a non-live suspend. Issue the call back to get the
@@ -703,23 +692,6 @@ xc_domain_save(int xc_handle, int io_fd,
goto out;
}
- if (hvm) {
- unsigned int j;
- /* Pull in the dirty bits from qemu-dm too */
- if (!last_iter) {
- qemu_active = qemu_non_active;
- qemu_non_active = qemu_active ? 0 : 1;
- qemu_flip_buffer(dom, qemu_active);
- for (j = 0; j < bitmap_size / sizeof(unsigned long); j++) {
- to_send[j] |= qemu_bitmaps[qemu_non_active][j];
- qemu_bitmaps[qemu_non_active][j] = 0;
- }
- } else {
- for (j = 0; j < bitmap_size / sizeof(unsigned long); j++)
- to_send[j] |= qemu_bitmaps[qemu_active][j];
- }
- }
-
sent_last_iter = sent_this_iter;
//print_stats(xc_handle, dom, sent_this_iter, &stats, 1);
@@ -762,6 +734,8 @@ xc_domain_save(int xc_handle, int io_fd,
NULL, 0, NULL, 0, NULL ) < 0) {
DPRINTF("Warning - couldn't disable shadow mode");
}
+ if ( hvm )
+ switch_qemu_logdirty(dom, 0);
}
unlock_pages(to_send, bitmap_size);
diff -r ead107bc25cb -r 49b561416efc tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c Fri Sep 04 08:43:05 2009 +0100
+++ b/tools/libxc/xc_domain_save.c Mon Sep 07 08:37:58 2009 +0100
@@ -38,11 +38,6 @@ static unsigned long hvirt_start;
/* #levels of page tables used by the current guest */
static unsigned int pt_levels;
-
-/* HVM: shared-memory bitmaps for getting log-dirty bits from qemu-dm */
-static unsigned long *qemu_bitmaps[2];
-static int qemu_active;
-static int qemu_non_active;
/* number of pfns this guest has (i.e. number of entries in the P2M) */
static unsigned long p2m_size;
@@ -748,8 +743,7 @@ static xen_pfn_t *map_and_save_p2m_table
int xc_domain_save(int xc_handle, int io_fd, uint32_t dom, uint32_t max_iters,
uint32_t max_factor, uint32_t flags, int (*suspend)(void),
- int hvm, void *(*init_qemu_maps)(int, unsigned),
- void (*qemu_flip_buffer)(int, int))
+ int hvm, void (*switch_qemu_logdirty)(int, unsigned))
{
xc_dominfo_t info;
DECLARE_DOMCTL;
@@ -863,15 +857,9 @@ int xc_domain_save(int xc_handle, int io
}
}
+ /* Enable qemu-dm logging dirty pages to xen */
if ( hvm )
- {
- /* Get qemu-dm logging dirty pages too */
- void *seg = init_qemu_maps(dom, BITMAP_SIZE);
- qemu_bitmaps[0] = seg;
- qemu_bitmaps[1] = seg + BITMAP_SIZE;
- qemu_active = 0;
- qemu_non_active = 1;
- }
+ switch_qemu_logdirty(dom, 1);
}
else
{
@@ -1341,27 +1329,6 @@ int xc_domain_save(int xc_handle, int io
goto out;
}
- if ( hvm )
- {
- /* Pull in the dirty bits from qemu-dm too */
- if ( !last_iter )
- {
- qemu_active = qemu_non_active;
- qemu_non_active = qemu_active ? 0 : 1;
- qemu_flip_buffer(dom, qemu_active);
- for ( j = 0; j < BITMAP_SIZE / sizeof(unsigned long); j++ )
- {
- to_send[j] |= qemu_bitmaps[qemu_non_active][j];
- qemu_bitmaps[qemu_non_active][j] = 0;
- }
- }
- else
- {
- for ( j = 0; j < BITMAP_SIZE / sizeof(unsigned long); j++ )
- to_send[j] |= qemu_bitmaps[qemu_active][j];
- }
- }
-
sent_last_iter = sent_this_iter;
print_stats(xc_handle, dom, sent_this_iter, &stats, 1);
@@ -1629,6 +1596,8 @@ int xc_domain_save(int xc_handle, int io
XEN_DOMCTL_SHADOW_OP_OFF,
NULL, 0, NULL, 0, NULL) < 0 )
DPRINTF("Warning - couldn't disable shadow mode");
+ if ( hvm )
+ switch_qemu_logdirty(dom, 0);
}
/* Flush last write and discard cache for file. */
diff -r ead107bc25cb -r 49b561416efc tools/libxc/xenguest.h
--- a/tools/libxc/xenguest.h Fri Sep 04 08:43:05 2009 +0100
+++ b/tools/libxc/xenguest.h Mon Sep 07 08:37:58 2009 +0100
@@ -26,8 +26,7 @@ int xc_domain_save(int xc_handle, int io
int xc_domain_save(int xc_handle, int io_fd, uint32_t dom, uint32_t max_iters,
uint32_t max_factor, uint32_t flags /* XCFLAGS_xxx */,
int (*suspend)(void), int hvm,
- void *(*init_qemu_maps)(int, unsigned), /* HVM only */
- void (*qemu_flip_buffer)(int, int)); /* HVM only */
+ void (*switch_qemu_logdirty)(int, unsigned)); /* HVM only */
/**
diff -r ead107bc25cb -r 49b561416efc tools/xcutils/xc_save.c
--- a/tools/xcutils/xc_save.c Fri Sep 04 08:43:05 2009 +0100
+++ b/tools/xcutils/xc_save.c Mon Sep 07 08:37:58 2009 +0100
@@ -101,115 +101,64 @@ static int suspend(void)
* the new active buffer. xc_save can then process and clear the old
* active buffer. */
-static char *qemu_active_path;
-static char *qemu_next_active_path;
-static int qemu_shmid = -1;
-static struct xs_handle *xs;
-
-
-/* Mark the shared-memory segment for destruction */
-static void qemu_destroy_buffer(void)
-{
- if (qemu_shmid != -1)
- shmctl(qemu_shmid, IPC_RMID, NULL);
- qemu_shmid = -1;
-}
-
-/* Get qemu to change buffers. */
-static void qemu_flip_buffer(int domid, int next_active)
-{
- char digit = '0' + next_active;
+
+static void switch_qemu_logdirty(int domid, unsigned int enable)
+{
+ struct xs_handle *xs;
+ char *path, *p, *ret_str, *cmd_str, **watch;
unsigned int len;
- char *active_str, **watch;
struct timeval tv;
fd_set fdset;
- /* Tell qemu that we want it to start writing log-dirty bits to the
- * other buffer */
- if (!xs_write(xs, XBT_NULL, qemu_next_active_path, &digit, 1))
- errx(1, "can't write next-active to store path (%s)\n",
- qemu_next_active_path);
-
- /* Wait a while for qemu to signal that it has switched to the new
- * active buffer */
- read_again:
- tv.tv_sec = 5;
- tv.tv_usec = 0;
- FD_ZERO(&fdset);
- FD_SET(xs_fileno(xs), &fdset);
- if ((select(xs_fileno(xs) + 1, &fdset, NULL, NULL, &tv)) != 1)
- errx(1, "timed out waiting for qemu to switch buffers\n");
- watch = xs_read_watch(xs, &len);
- free(watch);
-
- active_str = xs_read(xs, XBT_NULL, qemu_active_path, &len);
- if (active_str == NULL || active_str[0] - '0' != next_active)
- /* Watch fired but value is not yet right */
- goto read_again;
-}
-
-static void *init_qemu_maps(int domid, unsigned int bitmap_size)
-{
- key_t key;
- char key_ascii[17] = {0,};
- void *seg;
- char *path, *p;
-
- /* Make a shared-memory segment */
- do {
- key = rand(); /* No security, just a sequence of numbers */
- qemu_shmid = shmget(key, 2 * bitmap_size,
- IPC_CREAT|IPC_EXCL|S_IRUSR|S_IWUSR);
- if (qemu_shmid == -1 && errno != EEXIST)
- errx(1, "can't get shmem to talk to qemu-dm");
- } while (qemu_shmid == -1);
-
- /* Remember to tidy up after ourselves */
- atexit(qemu_destroy_buffer);
-
- /* Map it into our address space */
- seg = shmat(qemu_shmid, NULL, 0);
- if (seg == (void *) -1)
- errx(1, "can't map shmem to talk to qemu-dm");
- memset(seg, 0, 2 * bitmap_size);
-
- /* Write the size of it into the first 32 bits */
- *(uint32_t *)seg = bitmap_size;
-
- /* Tell qemu about it */
if ((xs = xs_daemon_open()) == NULL)
errx(1, "Couldn't contact xenstore");
if (!(path = strdup("/local/domain/0/device-model/")))
errx(1, "can't get domain path in store");
if (!(path = realloc(path, strlen(path)
+ 10
- + strlen("/logdirty/next-active") + 1)))
+ + strlen("/logdirty/cmd") + 1)))
errx(1, "no memory for constructing xenstore path");
snprintf(path + strlen(path), 11, "%i", domid);
strcat(path, "/logdirty/");
p = path + strlen(path);
- strcpy(p, "key");
- snprintf(key_ascii, 17, "%16.16llx", (unsigned long long) key);
- if (!xs_write(xs, XBT_NULL, path, key_ascii, 16))
- errx(1, "can't write key (%s) to store path (%s)\n", key_ascii, path);
-
- /* Watch for qemu's indication of the active buffer, and request it
- * to start writing to buffer 0 */
- strcpy(p, "active");
- if (!xs_watch(xs, path, "qemu-active-buffer"))
+
+ /* Watch for qemu's return value */
+ strcpy(p, "ret");
+ if (!xs_watch(xs, path, "qemu-logdirty-ret"))
errx(1, "can't set watch in store (%s)\n", path);
- if (!(qemu_active_path = strdup(path)))
- errx(1, "no memory for copying xenstore path");
-
- strcpy(p, "next-active");
- if (!(qemu_next_active_path = strdup(path)))
- errx(1, "no memory for copying xenstore path");
-
- qemu_flip_buffer(domid, 0);
+
+ if (!(cmd_str = strdup( enable == 0 ? "disable" : "enable")))
+ errx(1, "can't get logdirty cmd path in store");
+
+ /* Tell qemu that we want it to start logging dirty page to Xen */
+ strcpy(p, "cmd");
+ if (!xs_write(xs, XBT_NULL, path, cmd_str, strlen(cmd_str)))
+ errx(1, "can't write to store path (%s)\n",
+ path);
+
+ /* Wait a while for qemu to signal that it has service logdirty command */
+ read_again:
+ tv.tv_sec = 5;
+ tv.tv_usec = 0;
+ FD_ZERO(&fdset);
+ FD_SET(xs_fileno(xs), &fdset);
+
+ if ((select(xs_fileno(xs) + 1, &fdset, NULL, NULL, &tv)) != 1)
+ errx(1, "timed out waiting for qemu logdirty response.\n");
+
+ watch = xs_read_watch(xs, &len);
+ free(watch);
+
+ strcpy(p, "ret");
+ ret_str = xs_read(xs, XBT_NULL, path, &len);
+ if (ret_str == NULL || strcmp(ret_str, cmd_str))
+ /* Watch fired but value is not yet right */
+ goto read_again;
free(path);
- return seg;
+ free(cmd_str);
+ free(ret_str);
}
int
@@ -255,7 +204,7 @@ main(int argc, char **argv)
}
ret = xc_domain_save(si.xc_fd, io_fd, si.domid, maxit, max_f, si.flags,
&suspend, !!(si.flags & XCFLAGS_HVM),
- &init_qemu_maps, &qemu_flip_buffer);
+ &switch_qemu_logdirty);
if (si.suspend_evtchn > 0)
xc_suspend_evtchn_release(si.xce, si.suspend_evtchn);
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