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Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-c
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue |
Date: |
Thu, 12 Nov 2015 14:20:35 +0000 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
* Peter Maydell (address@hidden) wrote:
> On 12 November 2015 at 13:18, Peter Maydell <address@hidden> wrote:
> > On 12 November 2015 at 13:08, Dr. David Alan Gilbert
> > <address@hidden> wrote:
> >> OK, can you try a simple migration by hand outside of the test harness;
> >> just something simple like:
> >>
> >> ./bin/qemu-system-x86_64 -M pc -nographic
> >> (qemu) migrate "exec: cat > /dev/null"
> >>
> >> and the same with q35 ?
> >
> > (qemu) migrate "exec: cat > /dev/null"
> > migrate_get_current do init of current_migration 65307
> > unqueue_page 65307
> > 0 qemu-system-x86_64 0x00000001067c01c3 qemu_mutex_lock
> > + 83
>
> This turns out to be because migrate_init() is corrupting the
> mutex memory when it does "memset(s, 0, sizeof(*s))". Presumably
> Linux's initialized-mutex is all-zeroes, but OSX's is not.
OK, thanks for finding that; I've just smoke tested the following
patch and will post it properly after I test it more thoroughly in
a couple of hours.
Dave
commit 689d4964442c3ee34a2dac77411a30b96c214288
Author: Dr. David Alan Gilbert <address@hidden>
Date: Thu Nov 12 14:10:33 2015 +0000
migration_init: Fix lock initialisation/make it explicit
Peter reported a lock error on MacOS after my a82d593b
patch.
migrate_get_current does one-time initialisation of
a bunch of variables.
migrate_init does reinitialisation even on a 2nd
migrate after a cancel.
The problem here was that I'd initialised the mutex
in migrate_get_current, and the memset in migrate_init
corrupted it.
Remove the memset and replace it by explicit initialisation
of fields that need initialising; this also turns out to be simpler
than the old code that had to preserve some fields.
Reported-by: Peter Maydell <address@hidden>
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Fixes: a82d593b
diff --git a/migration/migration.c b/migration/migration.c
index 9bd2ce7..7e4e27b 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -902,38 +902,31 @@ bool migration_in_postcopy(MigrationState *s)
MigrationState *migrate_init(const MigrationParams *params)
{
MigrationState *s = migrate_get_current();
- int64_t bandwidth_limit = s->bandwidth_limit;
- bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
- int64_t xbzrle_cache_size = s->xbzrle_cache_size;
- int compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
- int compress_thread_count =
- s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
- int decompress_thread_count =
- s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
- int x_cpu_throttle_initial =
- s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
- int x_cpu_throttle_increment =
- s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
-
- memcpy(enabled_capabilities, s->enabled_capabilities,
- sizeof(enabled_capabilities));
- memset(s, 0, sizeof(*s));
+ /*
+ * Reinitialise all migration state, except
+ * parameters/capabilities that the user set, and
+ * locks.
+ */
+ s->bytes_xfer = 0;
+ s->xfer_limit = 0;
+ s->cleanup_bh = 0;
+ s->file = NULL;
+ s->state = MIGRATION_STATUS_NONE;
s->params = *params;
- memcpy(s->enabled_capabilities, enabled_capabilities,
- sizeof(enabled_capabilities));
- s->xbzrle_cache_size = xbzrle_cache_size;
-
- s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
- s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
- compress_thread_count;
- s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
- decompress_thread_count;
- s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =
- x_cpu_throttle_initial;
- s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
- x_cpu_throttle_increment;
- s->bandwidth_limit = bandwidth_limit;
+ s->rp_state.from_dst_file = NULL;
+ s->rp_state.error = false;
+ s->mbps = 0.0;
+ s->downtime = 0;
+ s->expected_downtime = 0;
+ s->dirty_pages_rate = 0;
+ s->dirty_bytes_rate = 0;
+ s->setup_time = 0;
+ s->dirty_sync_count = 0;
+ s->start_postcopy = false;
+ s->migration_thread_running = false;
+ s->last_req_rb = NULL;
+
migrate_set_state(s, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);
QSIMPLEQ_INIT(&s->src_page_requests);
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PULL 44/57] Postcopy: Use helpers to map pages during migration, (continued)
- [Qemu-devel] [PULL 44/57] Postcopy: Use helpers to map pages during migration, Juan Quintela, 2015/11/10
- [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Juan Quintela, 2015/11/10
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Peter Maydell, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Peter Maydell, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Peter Maydell, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Peter Maydell, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Peter Maydell, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue,
Dr. David Alan Gilbert <=
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Juan Quintela, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Juan Quintela, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Markus Armbruster, 2015/11/12
- Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue, Andreas Färber, 2015/11/16
[Qemu-devel] [PULL 43/57] postcopy_ram.c: place_page and helpers, Juan Quintela, 2015/11/10
[Qemu-devel] [PULL 45/57] postcopy: Check order of received target pages, Juan Quintela, 2015/11/10
[Qemu-devel] [PULL 46/57] Don't sync dirty bitmaps in postcopy, Juan Quintela, 2015/11/10
[Qemu-devel] [PULL 51/57] Start up a postcopy/listener thread ready for incoming page data, Juan Quintela, 2015/11/10
[Qemu-devel] [PULL 50/57] Postcopy; Handle userfault requests, Juan Quintela, 2015/11/10