| Message ID | 20200506094948.76388-6-david@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | virtio-mem: Paravirtualized memory hot(un)plug | expand |
* David Hildenbrand (david@redhat.com) wrote: > The only remaining special case is postcopy. It cannot handle > concurrent discards yet, which would result in requesting already sent > pages from the source. Special-case it in virtio-balloon instead. > > Cc: "Michael S. Tsirkin" <mst@redhat.com> > Cc: Juan Quintela <quintela@redhat.com> > Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > balloon.c | 18 ------------------ > hw/virtio/virtio-balloon.c | 12 +++++++++++- > include/sysemu/balloon.h | 2 -- > migration/postcopy-ram.c | 23 ----------------------- > 4 files changed, 11 insertions(+), 44 deletions(-) > > diff --git a/balloon.c b/balloon.c > index c49f57c27b..354408c6ea 100644 > --- a/balloon.c > +++ b/balloon.c > @@ -36,24 +36,6 @@ > static QEMUBalloonEvent *balloon_event_fn; > static QEMUBalloonStatus *balloon_stat_fn; > static void *balloon_opaque; > -static int balloon_inhibit_count; > - > -bool qemu_balloon_is_inhibited(void) > -{ > - return atomic_read(&balloon_inhibit_count) > 0 || > - ram_block_discard_is_broken(); > -} > - > -void qemu_balloon_inhibit(bool state) > -{ > - if (state) { > - atomic_inc(&balloon_inhibit_count); > - } else { > - atomic_dec(&balloon_inhibit_count); > - } > - > - assert(atomic_read(&balloon_inhibit_count) >= 0); > -} > > static bool have_balloon(Error **errp) > { > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index a4729f7fc9..aa5b89fb47 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -29,6 +29,7 @@ > #include "trace.h" > #include "qemu/error-report.h" > #include "migration/misc.h" > +#include "migration/postcopy-ram.h" > > #include "hw/virtio/virtio-bus.h" > #include "hw/virtio/virtio-access.h" > @@ -63,6 +64,15 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, > return pbp->base_gpa == base_gpa; > } > > +static bool virtio_balloon_inhibited(void) > +{ > + PostcopyState ps = postcopy_state_get(); > + > + /* Postcopy cannot deal with concurrent discards (yet), so it's special. */ > + return ram_block_discard_is_broken() || > + (ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END); It's a shame this is open-coded here; it would be better to have something in migration.c ; we have a migration_in_postcopy but that's really the sending side; a 'migration_in_incoming_postcopy' would perhaps be good. Dave > +} > + > static void balloon_inflate_page(VirtIOBalloon *balloon, > MemoryRegion *mr, hwaddr mr_offset, > PartiallyBalloonedPage *pbp) > @@ -360,7 +370,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) > > trace_virtio_balloon_handle_output(memory_region_name(section.mr), > pa); > - if (!qemu_balloon_is_inhibited()) { > + if (!virtio_balloon_inhibited()) { > if (vq == s->ivq) { > balloon_inflate_page(s, section.mr, > section.offset_within_region, &pbp); > diff --git a/include/sysemu/balloon.h b/include/sysemu/balloon.h > index aea0c44985..20a2defe3a 100644 > --- a/include/sysemu/balloon.h > +++ b/include/sysemu/balloon.h > @@ -23,7 +23,5 @@ typedef void (QEMUBalloonStatus)(void *opaque, BalloonInfo *info); > int qemu_add_balloon_handler(QEMUBalloonEvent *event_func, > QEMUBalloonStatus *stat_func, void *opaque); > void qemu_remove_balloon_handler(void *opaque); > -bool qemu_balloon_is_inhibited(void); > -void qemu_balloon_inhibit(bool state); > > #endif > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index a36402722b..b41a9fe2fd 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -27,7 +27,6 @@ > #include "qemu/notify.h" > #include "qemu/rcu.h" > #include "sysemu/sysemu.h" > -#include "sysemu/balloon.h" > #include "qemu/error-report.h" > #include "trace.h" > #include "hw/boards.h" > @@ -520,20 +519,6 @@ int postcopy_ram_incoming_init(MigrationIncomingState *mis) > return 0; > } > > -/* > - * Manage a single vote to the QEMU balloon inhibitor for all postcopy usage, > - * last caller wins. > - */ > -static void postcopy_balloon_inhibit(bool state) > -{ > - static bool cur_state = false; > - > - if (state != cur_state) { > - qemu_balloon_inhibit(state); > - cur_state = state; > - } > -} > - > /* > * At the end of a migration where postcopy_ram_incoming_init was called. > */ > @@ -565,8 +550,6 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) > mis->have_fault_thread = false; > } > > - postcopy_balloon_inhibit(false); > - > if (enable_mlock) { > if (os_mlock() < 0) { > error_report("mlock: %s", strerror(errno)); > @@ -1160,12 +1143,6 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis) > } > memset(mis->postcopy_tmp_zero_page, '\0', mis->largest_page_size); > > - /* > - * Ballooning can mark pages as absent while we're postcopying > - * that would cause false userfaults. > - */ > - postcopy_balloon_inhibit(true); > - > trace_postcopy_ram_enable_notify(); > > return 0; > -- > 2.25.3 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On 15.05.20 14:09, Dr. David Alan Gilbert wrote: > * David Hildenbrand (david@redhat.com) wrote: >> The only remaining special case is postcopy. It cannot handle >> concurrent discards yet, which would result in requesting already sent >> pages from the source. Special-case it in virtio-balloon instead. >> >> Cc: "Michael S. Tsirkin" <mst@redhat.com> >> Cc: Juan Quintela <quintela@redhat.com> >> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> >> Signed-off-by: David Hildenbrand <david@redhat.com> >> --- >> balloon.c | 18 ------------------ >> hw/virtio/virtio-balloon.c | 12 +++++++++++- >> include/sysemu/balloon.h | 2 -- >> migration/postcopy-ram.c | 23 ----------------------- >> 4 files changed, 11 insertions(+), 44 deletions(-) >> >> diff --git a/balloon.c b/balloon.c >> index c49f57c27b..354408c6ea 100644 >> --- a/balloon.c >> +++ b/balloon.c >> @@ -36,24 +36,6 @@ >> static QEMUBalloonEvent *balloon_event_fn; >> static QEMUBalloonStatus *balloon_stat_fn; >> static void *balloon_opaque; >> -static int balloon_inhibit_count; >> - >> -bool qemu_balloon_is_inhibited(void) >> -{ >> - return atomic_read(&balloon_inhibit_count) > 0 || >> - ram_block_discard_is_broken(); >> -} >> - >> -void qemu_balloon_inhibit(bool state) >> -{ >> - if (state) { >> - atomic_inc(&balloon_inhibit_count); >> - } else { >> - atomic_dec(&balloon_inhibit_count); >> - } >> - >> - assert(atomic_read(&balloon_inhibit_count) >= 0); >> -} >> >> static bool have_balloon(Error **errp) >> { >> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c >> index a4729f7fc9..aa5b89fb47 100644 >> --- a/hw/virtio/virtio-balloon.c >> +++ b/hw/virtio/virtio-balloon.c >> @@ -29,6 +29,7 @@ >> #include "trace.h" >> #include "qemu/error-report.h" >> #include "migration/misc.h" >> +#include "migration/postcopy-ram.h" >> >> #include "hw/virtio/virtio-bus.h" >> #include "hw/virtio/virtio-access.h" >> @@ -63,6 +64,15 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, >> return pbp->base_gpa == base_gpa; >> } >> >> +static bool virtio_balloon_inhibited(void) >> +{ >> + PostcopyState ps = postcopy_state_get(); >> + >> + /* Postcopy cannot deal with concurrent discards (yet), so it's special. */ >> + return ram_block_discard_is_broken() || >> + (ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END); > > It's a shame this is open-coded here; it would be better to have > something in migration.c ; we have a migration_in_postcopy but that's > really the sending side; a 'migration_in_incoming_postcopy' would > perhaps be good. Yes, makes sense - then I can also reuse it in patch #10. Thanks!
diff --git a/balloon.c b/balloon.c index c49f57c27b..354408c6ea 100644 --- a/balloon.c +++ b/balloon.c @@ -36,24 +36,6 @@ static QEMUBalloonEvent *balloon_event_fn; static QEMUBalloonStatus *balloon_stat_fn; static void *balloon_opaque; -static int balloon_inhibit_count; - -bool qemu_balloon_is_inhibited(void) -{ - return atomic_read(&balloon_inhibit_count) > 0 || - ram_block_discard_is_broken(); -} - -void qemu_balloon_inhibit(bool state) -{ - if (state) { - atomic_inc(&balloon_inhibit_count); - } else { - atomic_dec(&balloon_inhibit_count); - } - - assert(atomic_read(&balloon_inhibit_count) >= 0); -} static bool have_balloon(Error **errp) { diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index a4729f7fc9..aa5b89fb47 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -29,6 +29,7 @@ #include "trace.h" #include "qemu/error-report.h" #include "migration/misc.h" +#include "migration/postcopy-ram.h" #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" @@ -63,6 +64,15 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, return pbp->base_gpa == base_gpa; } +static bool virtio_balloon_inhibited(void) +{ + PostcopyState ps = postcopy_state_get(); + + /* Postcopy cannot deal with concurrent discards (yet), so it's special. */ + return ram_block_discard_is_broken() || + (ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END); +} + static void balloon_inflate_page(VirtIOBalloon *balloon, MemoryRegion *mr, hwaddr mr_offset, PartiallyBalloonedPage *pbp) @@ -360,7 +370,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) trace_virtio_balloon_handle_output(memory_region_name(section.mr), pa); - if (!qemu_balloon_is_inhibited()) { + if (!virtio_balloon_inhibited()) { if (vq == s->ivq) { balloon_inflate_page(s, section.mr, section.offset_within_region, &pbp); diff --git a/include/sysemu/balloon.h b/include/sysemu/balloon.h index aea0c44985..20a2defe3a 100644 --- a/include/sysemu/balloon.h +++ b/include/sysemu/balloon.h @@ -23,7 +23,5 @@ typedef void (QEMUBalloonStatus)(void *opaque, BalloonInfo *info); int qemu_add_balloon_handler(QEMUBalloonEvent *event_func, QEMUBalloonStatus *stat_func, void *opaque); void qemu_remove_balloon_handler(void *opaque); -bool qemu_balloon_is_inhibited(void); -void qemu_balloon_inhibit(bool state); #endif diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index a36402722b..b41a9fe2fd 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -27,7 +27,6 @@ #include "qemu/notify.h" #include "qemu/rcu.h" #include "sysemu/sysemu.h" -#include "sysemu/balloon.h" #include "qemu/error-report.h" #include "trace.h" #include "hw/boards.h" @@ -520,20 +519,6 @@ int postcopy_ram_incoming_init(MigrationIncomingState *mis) return 0; } -/* - * Manage a single vote to the QEMU balloon inhibitor for all postcopy usage, - * last caller wins. - */ -static void postcopy_balloon_inhibit(bool state) -{ - static bool cur_state = false; - - if (state != cur_state) { - qemu_balloon_inhibit(state); - cur_state = state; - } -} - /* * At the end of a migration where postcopy_ram_incoming_init was called. */ @@ -565,8 +550,6 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) mis->have_fault_thread = false; } - postcopy_balloon_inhibit(false); - if (enable_mlock) { if (os_mlock() < 0) { error_report("mlock: %s", strerror(errno)); @@ -1160,12 +1143,6 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis) } memset(mis->postcopy_tmp_zero_page, '\0', mis->largest_page_size); - /* - * Ballooning can mark pages as absent while we're postcopying - * that would cause false userfaults. - */ - postcopy_balloon_inhibit(true); - trace_postcopy_ram_enable_notify(); return 0;
The only remaining special case is postcopy. It cannot handle concurrent discards yet, which would result in requesting already sent pages from the source. Special-case it in virtio-balloon instead. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Juan Quintela <quintela@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> --- balloon.c | 18 ------------------ hw/virtio/virtio-balloon.c | 12 +++++++++++- include/sysemu/balloon.h | 2 -- migration/postcopy-ram.c | 23 ----------------------- 4 files changed, 11 insertions(+), 44 deletions(-)