* David Gibson (da...@gibson.dropbear.id.au) wrote:
> On Fri, Oct 03, 2014 at 06:47:42PM +0100, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
> >
> > On receiving MIG_RPCOMM_REQPAGES look up the address and
> > queue the page.
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > ---
> > arch_init.c | 52
> > +++++++++++++++++++++++++++++++++++++++++++
> > include/migration/migration.h | 21 +++++++++++++++++
> > include/qemu/typedefs.h | 3 ++-
> > migration.c | 34 +++++++++++++++++++++++++++-
> > 4 files changed, 108 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch_init.c b/arch_init.c
> > index 4a03171..72f9e17 100644
> > --- a/arch_init.c
> > +++ b/arch_init.c
> > @@ -660,6 +660,58 @@ static int ram_save_page(QEMUFile *f, RAMBlock* block,
> > ram_addr_t offset,
> > }
> >
> > /*
> > + * Queue the pages for transmission, e.g. a request from postcopy
> > destination
> > + * ms: MigrationStatus in which the queue is held
> > + * rbname: The RAMBlock the request is for - may be NULL (to mean reuse
> > last)
> > + * start: Offset from the start of the RAMBlock
> > + * len: Length (in bytes) to send
> > + * Return: 0 on success
> > + */
> > +int ram_save_queue_pages(MigrationState *ms, const char *rbname,
> > + ram_addr_t start, ram_addr_t len)
> > +{
> > + RAMBlock *ramblock;
> > +
> > + if (!rbname) {
> > + /* Reuse last RAMBlock */
> > + ramblock = ms->last_req_rb;
> > +
> > + if (!ramblock) {
> > + error_report("ram_save_queue_pages no previous block");
> > + return -1;
>
> This should be an assert() shouldn't it?
>
> > + }
> > + } else {
> > + ramblock = ram_find_block(rbname);
> > +
> > + if (!ramblock) {
> > + error_report("ram_save_queue_pages no block '%s'", rbname);
> > + return -1;
> > + }
>
> And maybe this one too - I would have expected the rb names to have
> already been validated on the source machine at this stage.
No to both:
I've been trying to avoid asserts in migration outgoing code, because
they shouldn't affect the state of your guest, so there's no reason
to kill off what might still be a viable running guest just because
migration failed.
(On the incoming side it's a bit more OK since if you've not got
a full running VM anyway yet then there's not much to lose).
Dave
>
> > + }
> > + DPRINTF("ram_save_queue_pages: Block %s start %zx len %zx",
> > + ramblock->idstr, start, len);
> > +
> > + if (start+len > ramblock->length) {
> > + error_report("%s request overrun start=%zx len=%zx blocklen=%zx",
> > + __func__, start, len, ramblock->length);
> > + return -1;
> > + }
> > +
> > + struct MigrationSrcPageRequest *new_entry =
> > + g_malloc0(sizeof(struct MigrationSrcPageRequest));
> > + new_entry->rb = ramblock;
> > + new_entry->offset = start;
> > + new_entry->len = len;
> > + ms->last_req_rb = ramblock;
> > +
> > + qemu_mutex_lock(&ms->src_page_req_mutex);
> > + QSIMPLEQ_INSERT_TAIL(&ms->src_page_requests, new_entry, next_req);
> > + qemu_mutex_unlock(&ms->src_page_req_mutex);
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > * ram_find_and_save_block: Finds a page to send and sends it to f
> > *
> > * Returns: The number of bytes written.
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index 5e0d30d..5bc01d5 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -102,6 +102,18 @@ MigrationIncomingState
> > *migration_incoming_get_current(void);
> > MigrationIncomingState *migration_incoming_state_init(QEMUFile *f);
> > void migration_incoming_state_destroy(void);
> >
> > +/*
> > + * An outstanding page request, on the source, having been received
> > + * and queued
> > + */
> > +struct MigrationSrcPageRequest {
> > + RAMBlock *rb;
> > + hwaddr offset;
> > + hwaddr len;
> > +
> > + QSIMPLEQ_ENTRY(MigrationSrcPageRequest) next_req;
> > +};
> > +
> > struct MigrationState
> > {
> > int64_t bandwidth_limit;
> > @@ -138,6 +150,12 @@ struct MigrationState
> > * of the postcopy phase
> > */
> > unsigned long *sentmap;
> > +
> > + /* Queue of outstanding page requests from the destination */
> > + QemuMutex src_page_req_mutex;
> > + QSIMPLEQ_HEAD(src_page_requests, MigrationSrcPageRequest)
> > src_page_requests;
> > + /* The RAMBlock used in the last src_page_request */
> > + RAMBlock *last_req_rb;
> > };
> >
> > void process_incoming_migration(QEMUFile *f);
> > @@ -273,4 +291,7 @@ size_t ram_control_save_page(QEMUFile *f, ram_addr_t
> > block_offset,
> > ram_addr_t offset, size_t size,
> > int *bytes_sent);
> >
> > +int ram_save_queue_pages(MigrationState *ms, const char *rbname,
> > + ram_addr_t start, ram_addr_t len);
> > +
> > #endif
> > diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
> > index 79f57c0..24c2207 100644
> > --- a/include/qemu/typedefs.h
> > +++ b/include/qemu/typedefs.h
> > @@ -8,6 +8,7 @@ typedef struct QEMUTimerListGroup QEMUTimerListGroup;
> > typedef struct QEMUFile QEMUFile;
> > typedef struct QEMUBH QEMUBH;
> >
> > +typedef struct AdapterInfo AdapterInfo;
> > typedef struct AioContext AioContext;
> >
> > typedef struct Visitor Visitor;
> > @@ -80,6 +81,6 @@ typedef struct FWCfgState FWCfgState;
> > typedef struct PcGuestInfo PcGuestInfo;
> > typedef struct PostcopyPMI PostcopyPMI;
> > typedef struct Range Range;
> > -typedef struct AdapterInfo AdapterInfo;
> > +typedef struct RAMBlock RAMBlock;
> >
> > #endif /* QEMU_TYPEDEFS_H */
> > diff --git a/migration.c b/migration.c
> > index cfdaa52..63d7699 100644
> > --- a/migration.c
> > +++ b/migration.c
> > @@ -26,6 +26,8 @@
> > #include "qemu/thread.h"
> > #include "qmp-commands.h"
> > #include "trace.h"
> > +#include "exec/memory.h"
> > +#include "exec/address-spaces.h"
> >
> > //#define DEBUG_MIGRATION
> >
> > @@ -504,6 +506,15 @@ static void migrate_fd_cleanup(void *opaque)
> >
> > migrate_fd_cleanup_src_rp(s);
> >
> > + /* This queue generally should be empty - but in the case of a failed
> > + * migration might have some droppings in.
> > + */
> > + struct MigrationSrcPageRequest *mspr, *next_mspr;
> > + QSIMPLEQ_FOREACH_SAFE(mspr, &s->src_page_requests, next_req,
> > next_mspr) {
> > + QSIMPLEQ_REMOVE_HEAD(&s->src_page_requests, next_req);
> > + g_free(mspr);
> > + }
> > +
> > if (s->file) {
> > trace_migrate_fd_cleanup();
> > qemu_mutex_unlock_iothread();
> > @@ -610,6 +621,9 @@ MigrationState *migrate_init(const MigrationParams
> > *params)
> > s->state = MIG_STATE_SETUP;
> > trace_migrate_set_state(MIG_STATE_SETUP);
> >
> > + qemu_mutex_init(&s->src_page_req_mutex);
> > + QSIMPLEQ_INIT(&s->src_page_requests);
> > +
> > s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> > return s;
> > }
> > @@ -823,7 +837,25 @@ static void source_return_path_bad(MigrationState *s)
> > static void migrate_handle_rp_reqpages(MigrationState *ms, const char*
> > rbname,
> > ram_addr_t start, ram_addr_t len)
> > {
> > - DPRINTF("migrate_handle_rp_reqpages: at %zx for len %zx", start, len);
> > + DPRINTF("migrate_handle_rp_reqpages: in %s start %zx len %zx",
> > + rbname, start, len);
> > +
> > + /* Round everything up to our host page size */
> > + long our_host_ps = sysconf(_SC_PAGESIZE);
> > + if (start & (our_host_ps-1)) {
> > + long roundings = start & (our_host_ps-1);
> > + start -= roundings;
> > + len += roundings;
> > + }
> > + if (len & (our_host_ps-1)) {
> > + long roundings = len & (our_host_ps-1);
> > + len -= roundings;
> > + len += our_host_ps;
> > + }
> > +
> > + if (ram_save_queue_pages(ms, rbname, start, len)) {
> > + source_return_path_bad(ms);
> > + }
> > }
> >
> > /*
>
> --
> David Gibson | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_
> _other_
> | _way_ _around_!
> http://www.ozlabs.org/~dgibson
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
