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[Qemu-devel] [PATCH v5 28/45] postcopy: Incoming initialisation
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH v5 28/45] postcopy: Incoming initialisation |
Date: |
Wed, 25 Feb 2015 16:51:51 +0000 |
From: "Dr. David Alan Gilbert" <address@hidden>
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
arch_init.c | 11 ++++
include/migration/migration.h | 3 +
include/migration/postcopy-ram.h | 12 ++++
migration/migration.c | 1 +
migration/postcopy-ram.c | 119 ++++++++++++++++++++++++++++++++++++++-
savevm.c | 4 ++
trace-events | 2 +
7 files changed, 151 insertions(+), 1 deletion(-)
diff --git a/arch_init.c b/arch_init.c
index 21e7ebe..d2c4457 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -1363,6 +1363,17 @@ 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)
{
int flags = 0, ret = 0;
diff --git a/include/migration/migration.h b/include/migration/migration.h
index e749f4c..d09561e 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -84,6 +84,8 @@ struct MigrationIncomingState {
PostcopyState postcopy_state;
+ /* For the kernel to send us notifications */
+ int userfault_fd;
QEMUFile *return_path;
QemuMutex rp_mutex; /* We send replies from multiple threads */
PostcopyPMI postcopy_pmi;
@@ -206,6 +208,7 @@ 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 1fec1c1..305c26b 100644
--- a/include/migration/postcopy-ram.h
+++ b/include/migration/postcopy-ram.h
@@ -19,6 +19,18 @@
bool postcopy_ram_supported_by_host(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/migration.c b/migration/migration.c
index 850fe1a..b1ad7b1 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -88,6 +88,7 @@ MigrationIncomingState
*migration_incoming_state_new(QEMUFile* f)
void migration_incoming_state_destroy(void)
{
+ postcopy_pmi_destroy(mis_current);
loadvm_free_handlers(mis_current);
g_free(mis_current);
mis_current = NULL;
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 391e9c6..dbe1892 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -74,7 +74,6 @@ struct PostcopyDiscardState {
/* the postcopy phase, there is no such guarantee during precopy. We */
/* could boil this down to only holding one bit per-host page, but we lose*/
/* sanity checking that we really do get whole host-pages from the source.*/
-__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();
@@ -392,6 +391,113 @@ 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;
+
+ trace_postcopy_init_area(block_name, host_addr, offset, 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.
+ * (Precopy will just overwrite this data, so doesn't need the discard)
+ */
+ 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 atopically place the
+ * 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.
+ */
+#ifdef MADV_NOHUGEPAGE
+ if (madvise(host_addr, length, MADV_NOHUGEPAGE)) {
+ perror("init_area: NOHUGEPAGE");
+ return -1;
+ }
+#endif
+
+ 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)
+{
+ MigrationIncomingState *mis = opaque;
+ struct uffdio_range range_struct;
+ trace_postcopy_cleanup_area(block_name, host_addr, offset, length);
+
+ /*
+ * We turned off hugepage for the precopy stage with postcopy enabled
+ * we can turn it back on now.
+ */
+#ifdef MADV_HUGEPAGE
+ if (madvise(host_addr, length, MADV_HUGEPAGE)) {
+ perror("cleanup_area: HUGEPAGE");
+ return -1;
+ }
+#endif
+
+ /*
+ * 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.
+ */
+ range_struct.start = (uint64_t)(uintptr_t)host_addr;
+ range_struct.len = (uint64_t)length;
+
+ if (ioctl(mis->userfault_fd, UFFDIO_UNREGISTER, &range_struct)) {
+ perror("cleanup_area: userfault unregister");
+
+ 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 */
@@ -408,6 +514,17 @@ 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 2589b8c..6857660 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1186,6 +1186,10 @@ static int
loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
return -1;
}
+ if (ram_postcopy_incoming_init(mis)) {
+ return -1;
+ }
+
postcopy_state_set(mis, POSTCOPY_INCOMING_ADVISE);
return 0;
diff --git a/trace-events b/trace-events
index f985117..59dea4c 100644
--- a/trace-events
+++ b/trace-events
@@ -1481,6 +1481,8 @@
rdma_start_outgoing_migration_after_rdma_source_init(void) ""
# migration/postcopy-ram.c
postcopy_discard_send_finish(const char *ramblock, int nwords, int ncmds) "%s
mask words sent=%d in %d commands"
+postcopy_cleanup_area(const char *ramblock, void *host_addr, size_t offset,
size_t length) "%s: %p offset=%zx length=%zx"
+postcopy_init_area(const char *ramblock, void *host_addr, size_t offset,
size_t length) "%s: %p offset=%zx length=%zx"
# kvm-all.c
kvm_ioctl(int type, void *arg) "type 0x%x, arg %p"
--
2.1.0
- [Qemu-devel] [PATCH v5 16/45] Add migration-capability boolean for postcopy-ram., (continued)
- [Qemu-devel] [PATCH v5 16/45] Add migration-capability boolean for postcopy-ram., Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 17/45] Add wrappers and handlers for sending/receiving the postcopy-ram migration messages., Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 21/45] Add Linux userfaultfd header, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 20/45] Modify savevm handlers for postcopy, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 24/45] MIG_STATE_POSTCOPY_ACTIVE: Add new migration state, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 22/45] postcopy: OS support test, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 23/45] migrate_start_postcopy: Command to trigger transition to postcopy, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 25/45] qemu_savevm_state_complete: Postcopy changes, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 26/45] Postcopy page-map-incoming (PMI) structure, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 29/45] postcopy: ram_enable_notify to switch on userfault, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 28/45] postcopy: Incoming initialisation,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH v5 27/45] Postcopy: Maintain sentmap and calculate discard, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 30/45] Postcopy: Postcopy startup in migration thread, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 31/45] Postcopy end in migration_thread, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 32/45] Page request: Add MIG_RP_CMD_REQ_PAGES reverse command, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 33/45] Page request: Process incoming page request, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 34/45] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 35/45] postcopy_ram.c: place_page and helpers, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 36/45] Postcopy: Use helpers to map pages during migration, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 38/45] Don't sync dirty bitmaps in postcopy, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 39/45] Host page!=target page: Cleanup bitmaps, Dr. David Alan Gilbert (git), 2015/02/25