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[Qemu-devel] [PATCH v4 31/47] postcopy: Incoming initialisation
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH v4 31/47] postcopy: Incoming initialisation |
Date: |
Fri, 3 Oct 2014 18:47:37 +0100 |
From: "Dr. David Alan Gilbert" <address@hidden>
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
arch_init.c | 11 ++++
include/migration/migration.h | 1 +
include/migration/postcopy-ram.h | 12 +++++
migration.c | 1 +
postcopy-ram.c | 110 ++++++++++++++++++++++++++++++++++++++-
savevm.c | 4 ++
6 files changed, 138 insertions(+), 1 deletion(-)
diff --git a/arch_init.c b/arch_init.c
index 030d189..4a03171 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -1345,6 +1345,17 @@ void ram_handle_compressed(void *host, uint8_t ch,
uint64_t size)
}
}
+/*
+ * Allocate data structures etc needed by incoming migration with postcopy-ram
+ * postcopy-ram's similarly names postcopy_ram_incoming_init does the work
+ */
+int ram_postcopy_incoming_init(MigrationIncomingState *mis)
+{
+ size_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
+
+ return postcopy_ram_incoming_init(mis, ram_pages);
+}
+
static int ram_load(QEMUFile *f, void *opaque, int version_id)
{
ram_addr_t addr;
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 73d338e..be63c89 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -203,6 +203,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms);
/* For incoming postcopy discard */
int ram_discard_range(MigrationIncomingState *mis, const char *block_name,
uint64_t start, uint64_t end);
+int ram_postcopy_incoming_init(MigrationIncomingState *mis);
/**
* @migrate_add_blocker - prevent migration from proceeding
diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h
index 2a39a03..8f237a2 100644
--- a/include/migration/postcopy-ram.h
+++ b/include/migration/postcopy-ram.h
@@ -19,6 +19,18 @@
int postcopy_ram_hosttest(void);
/*
+ * Initialise postcopy-ram, setting the RAM to a state where we can go into
+ * postcopy later; must be called prior to any precopy.
+ * called from arch_init's similarly named ram_postcopy_incoming_init
+ */
+int postcopy_ram_incoming_init(MigrationIncomingState *mis, size_t ram_pages);
+
+/*
+ * At the end of a migration where postcopy_ram_incoming_init was called.
+ */
+int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis);
+
+/*
* In 'advise' mode record that a page has been received.
*/
void postcopy_hook_early_receive(MigrationIncomingState *mis,
diff --git a/migration.c b/migration.c
index db860c9..63d70b6 100644
--- a/migration.c
+++ b/migration.c
@@ -99,6 +99,7 @@ MigrationIncomingState
*migration_incoming_state_init(QEMUFile* f)
void migration_incoming_state_destroy(void)
{
+ postcopy_pmi_destroy(mis_current);
g_free(mis_current);
mis_current = NULL;
}
diff --git a/postcopy-ram.c b/postcopy-ram.c
index 76f992f..8eccf26 100644
--- a/postcopy-ram.c
+++ b/postcopy-ram.c
@@ -104,7 +104,6 @@ struct PostcopyDiscardState {
/* It's a pair of bitmaps (of the same structure as the migration bitmaps)*/
/* holding one bit per target-page, although all operations work on host */
/* pages. */
-__attribute__ (( unused )) /* Until later in patch series */
static void postcopy_pmi_init(MigrationIncomingState *mis, size_t ram_pages)
{
unsigned int tpb = qemu_target_page_bits();
@@ -388,6 +387,104 @@ int postcopy_ram_discard_range(MigrationIncomingState
*mis, uint8_t *start,
return 0;
}
+/*
+ * Setup an area of RAM so that it *can* be used for postcopy later; this
+ * must be done right at the start prior to pre-copy.
+ * opaque should be the MIS.
+ */
+static int init_area(const char *block_name, void *host_addr,
+ ram_addr_t offset, ram_addr_t length, void *opaque)
+{
+ MigrationIncomingState *mis = opaque;
+
+ DPRINTF("init_area: %s: %p offset=%zx length=%zd(%zx)",
+ block_name, host_addr, offset, length, length);
+ /*
+ * We need the whole of RAM to be truly empty for postcopy, so things
+ * like ROMs and any data tables built during init must be zero'd
+ * - we're going to get the copy from the source anyway.
+ */
+ if (postcopy_ram_discard_range(mis, host_addr, (host_addr + length - 1))) {
+ return -1;
+ }
+
+ /*
+ * We also need the area to be normal 4k pages, not huge pages
+ * (otherwise we can't be sure we can use remap_anon_pages to put
+ * a 4k page in later). THP might come along and map a 2MB page
+ * and when it's partially accessed in precopy it might not break
+ * it down, but leave a 2MB zero'd page.
+ */
+ if (madvise(host_addr, length, MADV_NOHUGEPAGE)) {
+ perror("init_area: NOHUGEPAGE");
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * At the end of migration, undo the effects of init_area
+ * opaque should be the MIS.
+ */
+static int cleanup_area(const char *block_name, void *host_addr,
+ ram_addr_t offset, ram_addr_t length, void *opaque)
+{
+ /* Turn off userfault here as well? */
+
+ DPRINTF("cleanup_area: %s: %p offset=%zx length=%zd(%zx)",
+ block_name, host_addr, offset, length, length);
+ /*
+ * We turned off hugepage for the precopy stage with postcopy enabled
+ * we can turn it back on now.
+ */
+ if (madvise(host_addr, length, MADV_HUGEPAGE)) {
+ perror("init_area: HUGEPAGE");
+ return -1;
+ }
+
+ /*
+ * We can also turn off userfault now since we should have all the
+ * pages. It can be useful to leave it on to debug postcopy
+ * if you're not sure it's always getting every page.
+ */
+ if (madvise(host_addr, length, MADV_NOUSERFAULT)) {
+ perror("init_area: NOUSERFAULT");
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Initialise postcopy-ram, setting the RAM to a state where we can go into
+ * postcopy later; must be called prior to any precopy.
+ * called from arch_init's similarly named ram_postcopy_incoming_init
+ */
+int postcopy_ram_incoming_init(MigrationIncomingState *mis, size_t ram_pages)
+{
+ postcopy_pmi_init(mis, ram_pages);
+
+ if (qemu_ram_foreach_block(init_area, mis)) {
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * At the end of a migration where postcopy_ram_incoming_init was called.
+ */
+int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
+{
+ /* TODO: Join the fault thread once we're sure it will exit */
+ if (qemu_ram_foreach_block(cleanup_area, mis)) {
+ return -1;
+ }
+
+ return 0;
+}
+
#else
/* No target OS support, stubs just fail */
@@ -404,6 +501,17 @@ void postcopy_hook_early_receive(MigrationIncomingState
*mis,
/* We don't support postcopy so don't care */
}
+int postcopy_ram_incoming_init(MigrationIncomingState *mis, size_t ram_pages)
+{
+ error_report("postcopy_ram_incoming_init: No OS support");
+ return -1;
+}
+
+int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
+{
+ assert(0);
+}
+
void postcopy_pmi_destroy(MigrationIncomingState *mis)
{
/* Called in normal cleanup path - so it's OK */
diff --git a/savevm.c b/savevm.c
index 7f9e0b2..54bdb26 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1166,6 +1166,10 @@ static int
loadvm_postcopy_ram_handle_advise(MigrationIncomingState *mis,
return -1;
}
+ if (ram_postcopy_incoming_init(mis)) {
+ return -1;
+ }
+
mis->postcopy_ram_state = POSTCOPY_RAM_INCOMING_ADVISE;
/*
--
1.9.3
- [Qemu-devel] [PATCH v4 22/47] QEMU_VM_CMD_PACKAGED: Send a packaged chunk of migration stream, (continued)
- [Qemu-devel] [PATCH v4 22/47] QEMU_VM_CMD_PACKAGED: Send a packaged chunk of migration stream, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 23/47] migrate_init: Call from savevm, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 24/47] Allow savevm handlers to state whether they could go into postcopy, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 25/47] postcopy: OS support test, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 26/47] migrate_start_postcopy: Command to trigger transition to postcopy, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 27/47] MIG_STATE_POSTCOPY_ACTIVE: Add new migration state, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 28/47] qemu_savevm_state_complete: Postcopy changes, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 29/47] Postcopy page-map-incoming (PMI) structure, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 30/47] Postcopy: Maintain sentmap and calculate discard, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 31/47] postcopy: Incoming initialisation,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH v4 32/47] postcopy: ram_enable_notify to switch on userfault, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 33/47] Postcopy: Postcopy startup in migration thread, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 35/47] Page request: Add MIG_RPCOMM_REQPAGES reverse command, Dr. David Alan Gilbert (git), 2014/10/03
- [Qemu-devel] [PATCH v4 36/47] Page request: Process incoming page request, Dr. David Alan Gilbert (git), 2014/10/03