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[Qemu-devel] [PATCH 26/46] Postcopy page-map-incoming (PMI) structure
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH 26/46] Postcopy page-map-incoming (PMI) structure |
Date: |
Fri, 4 Jul 2014 18:41:37 +0100 |
From: "Dr. David Alan Gilbert" <address@hidden>
The PMI holds the state of each page on the incoming side,
so that we can tell if the page is missing, already received
or there is a request outstanding for it.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
include/migration/migration.h | 18 ++++++
include/migration/postcopy-ram.h | 4 ++
include/qemu/typedefs.h | 1 +
postcopy-ram.c | 118 +++++++++++++++++++++++++++++++++++++++
4 files changed, 141 insertions(+)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 2289254..722c846 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -57,6 +57,23 @@ struct MigrationRetPathState {
typedef struct MigrationState MigrationState;
+/* Postcopy page-map-incoming - data about each page on the inbound side */
+
+typedef enum {
+ POSTCOPY_PMI_MISSING, /* page hasn't yet been received */
+ POSTCOPY_PMI_REQUESTED, /* Kernel asked for a page, but we've not got it */
+ POSTCOPY_PMI_RECEIVED /* We've got the page */
+} PostcopyPMIState;
+
+struct PostcopyPMI {
+ /* TODO: I'm expecting to rework this using some atomic compare-exchange
+ * thing, which will require merging the maps together
+ */
+ QemuMutex mutex;
+ unsigned long *received_map; /* Pages that we have received */
+ unsigned long *requested_map; /* Pages that we're sending a request for */
+};
+
/* State for the incoming migration */
struct MigrationIncomingState {
QEMUFile *file;
@@ -71,6 +88,7 @@ struct MigrationIncomingState {
QEMUFile *return_path;
QemuMutex rp_mutex; /* We send replies from multiple threads */
+ PostcopyPMI postcopy_pmi;
};
MigrationIncomingState *migration_incoming_state_init(QEMUFile *f);
diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h
index fe89a3c..75ca0fd 100644
--- a/include/migration/postcopy-ram.h
+++ b/include/migration/postcopy-ram.h
@@ -36,4 +36,8 @@ int postcopy_ram_discard_range(MigrationIncomingState *mis,
uint8_t *start,
int postcopy_send_discard_bm_ram(MigrationState *ms, const char *name,
unsigned long start, unsigned long end);
+void postcopy_pmi_destroy(MigrationIncomingState *mis);
+void postcopy_pmi_discard_range(MigrationIncomingState *mis,
+ size_t start, size_t npages);
+
#endif
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 8539de6..61b330c 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -77,6 +77,7 @@ typedef struct QEMUSGList QEMUSGList;
typedef struct SHPCDevice SHPCDevice;
typedef struct FWCfgState FWCfgState;
typedef struct PcGuestInfo PcGuestInfo;
+typedef struct PostcopyPMI PostcopyPMI;
typedef struct Range Range;
typedef struct AdapterInfo AdapterInfo;
diff --git a/postcopy-ram.c b/postcopy-ram.c
index ff6bdd6..f92f516 100644
--- a/postcopy-ram.c
+++ b/postcopy-ram.c
@@ -23,6 +23,8 @@
#include "qemu-common.h"
#include "migration/migration.h"
#include "migration/postcopy-ram.h"
+#include "qemu/bitmap.h"
+#include "qemu/error-report.h"
#include "sysemu/sysemu.h"
//#define DEBUG_POSTCOPY
@@ -66,6 +68,122 @@
#define __NR_remap_anon_pages 317
#endif
+/* ---------------------------------------------------------------------- */
+/* Postcopy pagemap-inbound (pmi) - data structures that record the */
+/* state of each page used by the inbound postcopy */
+
+static void postcopy_pmi_init(MigrationIncomingState *mis, size_t ram_pages)
+{
+ qemu_mutex_init(&mis->postcopy_pmi.mutex);
+ mis->postcopy_pmi.received_map = bitmap_new(ram_pages);
+ mis->postcopy_pmi.requested_map = bitmap_new(ram_pages);
+ bitmap_clear(mis->postcopy_pmi.received_map, 0, ram_pages);
+ bitmap_clear(mis->postcopy_pmi.requested_map, 0, ram_pages);
+}
+
+void postcopy_pmi_destroy(MigrationIncomingState *mis)
+{
+ if (mis->postcopy_pmi.received_map) {
+ g_free(mis->postcopy_pmi.received_map);
+ mis->postcopy_pmi.received_map = NULL;
+ }
+ if (mis->postcopy_pmi.requested_map) {
+ g_free(mis->postcopy_pmi.requested_map);
+ mis->postcopy_pmi.requested_map = NULL;
+ }
+ qemu_mutex_destroy(&mis->postcopy_pmi.mutex);
+}
+
+/*
+ * Mark a set of pages in the PMI as being clear; this is used by the discard
+ * at the start of postcopy, and before the postcopy stream starts.
+ */
+void postcopy_pmi_discard_range(MigrationIncomingState *mis,
+ size_t start, size_t npages)
+{
+ bitmap_clear(mis->postcopy_pmi.received_map, start, npages);
+}
+
+/*
+ * Retrieve the state of the given page
+ * Note: This version for use by callers already holding the lock
+ */
+static PostcopyPMIState postcopy_pmi_get_state_nolock(
+ MigrationIncomingState *mis,
+ size_t bitmap_index)
+{
+ bool received, requested;
+
+ received = test_bit(bitmap_index, mis->postcopy_pmi.received_map);
+ requested = test_bit(bitmap_index, mis->postcopy_pmi.requested_map);
+
+ if (received) {
+ assert(!requested);
+ return POSTCOPY_PMI_RECEIVED;
+ } else {
+ return requested ? POSTCOPY_PMI_REQUESTED : POSTCOPY_PMI_MISSING;
+ }
+}
+
+/* Retrieve the state of the given page */
+static PostcopyPMIState postcopy_pmi_get_state(MigrationIncomingState *mis,
+ size_t bitmap_index)
+{
+ PostcopyPMIState ret;
+ qemu_mutex_lock(&mis->postcopy_pmi.mutex);
+ ret = postcopy_pmi_get_state_nolock(mis, bitmap_index);
+ qemu_mutex_unlock(&mis->postcopy_pmi.mutex);
+
+ return ret;
+}
+
+/*
+ * Set the page state to the given state if the previous state was as expected
+ * Return the actual previous state.
+ */
+static PostcopyPMIState postcopy_pmi_change_state(MigrationIncomingState *mis,
+ size_t bitmap_index,
+ PostcopyPMIState expected_state,
+ PostcopyPMIState new_state)
+{
+ PostcopyPMIState old_state;
+
+ qemu_mutex_lock(&mis->postcopy_pmi.mutex);
+ old_state = postcopy_pmi_get_state_nolock(mis, bitmap_index);
+
+ if (old_state == expected_state) {
+ switch (new_state) {
+ case POSTCOPY_PMI_MISSING:
+ assert(0); /* This shouldn't actually happen - use discard_range */
+ break;
+
+ case POSTCOPY_PMI_REQUESTED:
+ assert(old_state == POSTCOPY_PMI_MISSING);
+ set_bit(bitmap_index, mis->postcopy_pmi.requested_map);
+ break;
+
+ case POSTCOPY_PMI_RECEIVED:
+ assert(old_state == POSTCOPY_PMI_MISSING ||
+ old_state == POSTCOPY_PMI_REQUESTED);
+ set_bit(bitmap_index, mis->postcopy_pmi.received_map);
+ clear_bit(bitmap_index, mis->postcopy_pmi.requested_map);
+ break;
+ }
+ }
+
+ qemu_mutex_unlock(&mis->postcopy_pmi.mutex);
+ return old_state;
+}
+
+static void postcopy_pmi_dump(MigrationIncomingState *mis)
+{
+ fprintf(stderr, "postcopy_pmi_dump: requested\n");
+ ram_debug_dump_bitmap(mis->postcopy_pmi.requested_map, false);
+ fprintf(stderr, "postcopy_pmi_dump: received\n");
+ ram_debug_dump_bitmap(mis->postcopy_pmi.received_map, true);
+}
+
+/* ---------------------------------------------------------------------- */
int postcopy_ram_hosttest(void)
{
/* TODO: Needs guarding with CONFIG_ once we have libc's that have the defs
--
1.9.3
- Re: [Qemu-devel] [PATCH 07/46] Return path: Open a return path on QEMUFile for sockets, (continued)
- [Qemu-devel] [PATCH 09/46] Migration commands, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 08/46] Return path: socket_writev_buffer: Block even on non-blocking fd's, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 10/46] Return path: Control commands, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 12/46] Return path: Source handling of return path, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 11/46] Return path: Send responses from destination to source, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 23/46] MIG_STATE_POSTCOPY_ACTIVE: Add new migration state, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 24/46] qemu_savevm_state_complete: Postcopy changes, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 25/46] Postcopy: Maintain sentmap during postcopy pre phase, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 26/46] Postcopy page-map-incoming (PMI) structure,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH 27/46] postcopy: Add incoming_init/cleanup functions, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 29/46] postcopy: ram_enable_notify to switch on userfault, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 28/46] postcopy: Incoming initialisation, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 30/46] Postcopy: postcopy_start, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 32/46] mig fd_connect: open return path, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 31/46] Postcopy: Rework migration thread for postcopy mode, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 33/46] Postcopy: Create a fault handler thread before marking the ram as userfault, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 34/46] Page request: Add MIG_RPCOMM_REQPAGES reverse command, Dr. David Alan Gilbert (git), 2014/07/04
- [Qemu-devel] [PATCH 36/46] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert (git), 2014/07/04