Message ID | 20180216131625.9639-18-dgilbert@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On Fri, Feb 16, 2018 at 01:16:13PM +0000, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Send requests back to the source for shared page requests. > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > migration/migration.h | 2 ++ > migration/postcopy-ram.c | 31 ++++++++++++++++++++++++++++--- > migration/postcopy-ram.h | 3 +++ > migration/trace-events | 2 ++ > 4 files changed, 35 insertions(+), 3 deletions(-) > > diff --git a/migration/migration.h b/migration/migration.h > index d158e62cf2..457bf37ec2 100644 > --- a/migration/migration.h > +++ b/migration/migration.h > @@ -46,6 +46,8 @@ struct MigrationIncomingState { > int userfault_quit_fd; > QEMUFile *to_src_file; > QemuMutex rp_mutex; /* We send replies from multiple threads */ > + /* RAMBlock of last request sent to source */ > + RAMBlock *last_rb; > void *postcopy_tmp_page; > void *postcopy_tmp_zero_page; > /* PostCopyFD's for external userfaultfds & handlers of shared memory */ > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index d118b78bf5..277ff749a0 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -534,6 +534,31 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr, > return 0; > } > > +/* > + * Callback from shared fault handlers to ask for a page, > + * the page must be specified by a RAMBlock and an offset in that rb > + */ > +int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, > + uint64_t client_addr, uint64_t rb_offset) > +{ > + size_t pagesize = qemu_ram_pagesize(rb); > + uint64_t aligned_rbo = rb_offset & ~(pagesize - 1); > + MigrationIncomingState *mis = migration_incoming_get_current(); > + > + trace_postcopy_request_shared_page(pcfd->idstr, qemu_ram_get_idstr(rb), > + rb_offset); > + /* TODO: Check bitmap to see if we already have the page */ > + if (rb != mis->last_rb) { > + mis->last_rb = rb; > + migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), > + aligned_rbo, pagesize); > + } else { > + /* Save some space */ > + migrate_send_rp_req_pages(mis, NULL, aligned_rbo, pagesize); > + } > + return 0; > +} > + So IIUC this can only be called within the page fault thread or there can be race. Is there a way to guarantee this? Or do we need a comment for that? > /* > * Handle faults detected by the USERFAULT markings > */ > @@ -544,9 +569,9 @@ static void *postcopy_ram_fault_thread(void *opaque) > int ret; > size_t index; > RAMBlock *rb = NULL; > - RAMBlock *last_rb = NULL; /* last RAMBlock we sent part of */ > > trace_postcopy_ram_fault_thread_entry(); > + mis->last_rb = NULL; /* last RAMBlock we sent part of */ > qemu_sem_post(&mis->fault_thread_sem); > > struct pollfd *pfd; > @@ -634,8 +659,8 @@ static void *postcopy_ram_fault_thread(void *opaque) > * Send the request to the source - we want to request one > * of our host page sizes (which is >= TPS) > */ > - if (rb != last_rb) { > - last_rb = rb; > + if (rb != mis->last_rb) { > + mis->last_rb = rb; > migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), > rb_offset, qemu_ram_pagesize(rb)); > } else { > diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h > index dbc2ee1f2b..4c63f20df4 100644 > --- a/migration/postcopy-ram.h > +++ b/migration/postcopy-ram.h > @@ -162,5 +162,8 @@ struct PostCopyFD { > */ > void postcopy_register_shared_ufd(struct PostCopyFD *pcfd); > void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd); > +/* Callback from shared fault handlers to ask for a page */ > +int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, > + uint64_t client_addr, uint64_t offset); > > #endif > diff --git a/migration/trace-events b/migration/trace-events > index 1e617ad7a6..7c910b5479 100644 > --- a/migration/trace-events > +++ b/migration/trace-events > @@ -198,6 +198,8 @@ postcopy_ram_incoming_cleanup_closeuf(void) "" > postcopy_ram_incoming_cleanup_entry(void) "" > postcopy_ram_incoming_cleanup_exit(void) "" > postcopy_ram_incoming_cleanup_join(void) "" > +postcopy_request_shared_page(const char *sharer, const char *rb, uint64_t rb_offset) "for %s in %s offset 0x%"PRIx64 > + > save_xbzrle_page_skipping(void) "" > save_xbzrle_page_overflow(void) "" > ram_save_iterate_big_wait(uint64_t milliconds, int iterations) "big wait: %" PRIu64 " milliseconds, %d iterations" > -- > 2.14.3 >
* Peter Xu (peterx@redhat.com) wrote: > On Fri, Feb 16, 2018 at 01:16:13PM +0000, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > > > Send requests back to the source for shared page requests. > > > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > > --- > > migration/migration.h | 2 ++ > > migration/postcopy-ram.c | 31 ++++++++++++++++++++++++++++--- > > migration/postcopy-ram.h | 3 +++ > > migration/trace-events | 2 ++ > > 4 files changed, 35 insertions(+), 3 deletions(-) > > > > diff --git a/migration/migration.h b/migration/migration.h > > index d158e62cf2..457bf37ec2 100644 > > --- a/migration/migration.h > > +++ b/migration/migration.h > > @@ -46,6 +46,8 @@ struct MigrationIncomingState { > > int userfault_quit_fd; > > QEMUFile *to_src_file; > > QemuMutex rp_mutex; /* We send replies from multiple threads */ > > + /* RAMBlock of last request sent to source */ > > + RAMBlock *last_rb; > > void *postcopy_tmp_page; > > void *postcopy_tmp_zero_page; > > /* PostCopyFD's for external userfaultfds & handlers of shared memory */ > > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > > index d118b78bf5..277ff749a0 100644 > > --- a/migration/postcopy-ram.c > > +++ b/migration/postcopy-ram.c > > @@ -534,6 +534,31 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr, > > return 0; > > } > > > > +/* > > + * Callback from shared fault handlers to ask for a page, > > + * the page must be specified by a RAMBlock and an offset in that rb > > + */ > > +int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, > > + uint64_t client_addr, uint64_t rb_offset) > > +{ > > + size_t pagesize = qemu_ram_pagesize(rb); > > + uint64_t aligned_rbo = rb_offset & ~(pagesize - 1); > > + MigrationIncomingState *mis = migration_incoming_get_current(); > > + > > + trace_postcopy_request_shared_page(pcfd->idstr, qemu_ram_get_idstr(rb), > > + rb_offset); > > + /* TODO: Check bitmap to see if we already have the page */ > > + if (rb != mis->last_rb) { > > + mis->last_rb = rb; > > + migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), > > + aligned_rbo, pagesize); > > + } else { > > + /* Save some space */ > > + migrate_send_rp_req_pages(mis, NULL, aligned_rbo, pagesize); > > + } > > + return 0; > > +} > > + > > So IIUC this can only be called within the page fault thread or there > can be race. Is there a way to guarantee this? Or do we need a > comment for that? I don't think there's a way to guarantee it - especially since it has to be called by the device-specific shared handlers in another file - I've updated the comment to: /* * Callback from shared fault handlers to ask for a page, * the page must be specified by a RAMBlock and an offset in that rb * Note: Only for use by shared fault handlers (in fault thread) */ Dave > > /* > > * Handle faults detected by the USERFAULT markings > > */ > > @@ -544,9 +569,9 @@ static void *postcopy_ram_fault_thread(void *opaque) > > int ret; > > size_t index; > > RAMBlock *rb = NULL; > > - RAMBlock *last_rb = NULL; /* last RAMBlock we sent part of */ > > > > trace_postcopy_ram_fault_thread_entry(); > > + mis->last_rb = NULL; /* last RAMBlock we sent part of */ > > qemu_sem_post(&mis->fault_thread_sem); > > > > struct pollfd *pfd; > > @@ -634,8 +659,8 @@ static void *postcopy_ram_fault_thread(void *opaque) > > * Send the request to the source - we want to request one > > * of our host page sizes (which is >= TPS) > > */ > > - if (rb != last_rb) { > > - last_rb = rb; > > + if (rb != mis->last_rb) { > > + mis->last_rb = rb; > > migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), > > rb_offset, qemu_ram_pagesize(rb)); > > } else { > > diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h > > index dbc2ee1f2b..4c63f20df4 100644 > > --- a/migration/postcopy-ram.h > > +++ b/migration/postcopy-ram.h > > @@ -162,5 +162,8 @@ struct PostCopyFD { > > */ > > void postcopy_register_shared_ufd(struct PostCopyFD *pcfd); > > void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd); > > +/* Callback from shared fault handlers to ask for a page */ > > +int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, > > + uint64_t client_addr, uint64_t offset); > > > > #endif > > diff --git a/migration/trace-events b/migration/trace-events > > index 1e617ad7a6..7c910b5479 100644 > > --- a/migration/trace-events > > +++ b/migration/trace-events > > @@ -198,6 +198,8 @@ postcopy_ram_incoming_cleanup_closeuf(void) "" > > postcopy_ram_incoming_cleanup_entry(void) "" > > postcopy_ram_incoming_cleanup_exit(void) "" > > postcopy_ram_incoming_cleanup_join(void) "" > > +postcopy_request_shared_page(const char *sharer, const char *rb, uint64_t rb_offset) "for %s in %s offset 0x%"PRIx64 > > + > > save_xbzrle_page_skipping(void) "" > > save_xbzrle_page_overflow(void) "" > > ram_save_iterate_big_wait(uint64_t milliconds, int iterations) "big wait: %" PRIu64 " milliseconds, %d iterations" > > -- > > 2.14.3 > > > > -- > Peter Xu -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/migration/migration.h b/migration/migration.h index d158e62cf2..457bf37ec2 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -46,6 +46,8 @@ struct MigrationIncomingState { int userfault_quit_fd; QEMUFile *to_src_file; QemuMutex rp_mutex; /* We send replies from multiple threads */ + /* RAMBlock of last request sent to source */ + RAMBlock *last_rb; void *postcopy_tmp_page; void *postcopy_tmp_zero_page; /* PostCopyFD's for external userfaultfds & handlers of shared memory */ diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index d118b78bf5..277ff749a0 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -534,6 +534,31 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr, return 0; } +/* + * Callback from shared fault handlers to ask for a page, + * the page must be specified by a RAMBlock and an offset in that rb + */ +int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, + uint64_t client_addr, uint64_t rb_offset) +{ + size_t pagesize = qemu_ram_pagesize(rb); + uint64_t aligned_rbo = rb_offset & ~(pagesize - 1); + MigrationIncomingState *mis = migration_incoming_get_current(); + + trace_postcopy_request_shared_page(pcfd->idstr, qemu_ram_get_idstr(rb), + rb_offset); + /* TODO: Check bitmap to see if we already have the page */ + if (rb != mis->last_rb) { + mis->last_rb = rb; + migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), + aligned_rbo, pagesize); + } else { + /* Save some space */ + migrate_send_rp_req_pages(mis, NULL, aligned_rbo, pagesize); + } + return 0; +} + /* * Handle faults detected by the USERFAULT markings */ @@ -544,9 +569,9 @@ static void *postcopy_ram_fault_thread(void *opaque) int ret; size_t index; RAMBlock *rb = NULL; - RAMBlock *last_rb = NULL; /* last RAMBlock we sent part of */ trace_postcopy_ram_fault_thread_entry(); + mis->last_rb = NULL; /* last RAMBlock we sent part of */ qemu_sem_post(&mis->fault_thread_sem); struct pollfd *pfd; @@ -634,8 +659,8 @@ static void *postcopy_ram_fault_thread(void *opaque) * Send the request to the source - we want to request one * of our host page sizes (which is >= TPS) */ - if (rb != last_rb) { - last_rb = rb; + if (rb != mis->last_rb) { + mis->last_rb = rb; migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), rb_offset, qemu_ram_pagesize(rb)); } else { diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h index dbc2ee1f2b..4c63f20df4 100644 --- a/migration/postcopy-ram.h +++ b/migration/postcopy-ram.h @@ -162,5 +162,8 @@ struct PostCopyFD { */ void postcopy_register_shared_ufd(struct PostCopyFD *pcfd); void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd); +/* Callback from shared fault handlers to ask for a page */ +int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, + uint64_t client_addr, uint64_t offset); #endif diff --git a/migration/trace-events b/migration/trace-events index 1e617ad7a6..7c910b5479 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -198,6 +198,8 @@ postcopy_ram_incoming_cleanup_closeuf(void) "" postcopy_ram_incoming_cleanup_entry(void) "" postcopy_ram_incoming_cleanup_exit(void) "" postcopy_ram_incoming_cleanup_join(void) "" +postcopy_request_shared_page(const char *sharer, const char *rb, uint64_t rb_offset) "for %s in %s offset 0x%"PRIx64 + save_xbzrle_page_skipping(void) "" save_xbzrle_page_overflow(void) "" ram_save_iterate_big_wait(uint64_t milliconds, int iterations) "big wait: %" PRIu64 " milliseconds, %d iterations"