On Fri, Feb 16, 2018 at 01:16:18PM +0000, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Cause the vhost-user client to be woken up whenever:
> a) We place a page in postcopy mode
> b) We get a fault and the page has already been received
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> migration/postcopy-ram.c | 14 ++++++++++----
> migration/trace-events | 1 +
> 2 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> index 879711968c..13561703b5 100644
> --- a/migration/postcopy-ram.c
> +++ b/migration/postcopy-ram.c
> @@ -566,7 +566,11 @@ int postcopy_request_shared_page(struct PostCopyFD
> *pcfd, RAMBlock *rb,
>
> 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 (ramblock_recv_bitmap_test_byte_offset(rb, aligned_rbo)) {
> + trace_postcopy_request_shared_page_present(pcfd->idstr,
> + qemu_ram_get_idstr(rb), rb_offset);
> + return postcopy_wake_shared(pcfd, client_addr, rb);
> + }
> if (rb != mis->last_rb) {
> mis->last_rb = rb;
> migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb),
> @@ -863,7 +867,8 @@ int postcopy_place_page(MigrationIncomingState *mis, void
> *host, void *from,
> }
>
> trace_postcopy_place_page(host);
> - return 0;
> + return postcopy_notify_shared_wake(rb,
> + qemu_ram_block_host_offset(rb, host));
> }
>
> /*
> @@ -887,6 +892,9 @@ int postcopy_place_page_zero(MigrationIncomingState *mis,
> void *host,
>
> return -e;
> }
> + return postcopy_notify_shared_wake(rb,
> + qemu_ram_block_host_offset(rb,
> + host));
> } else {
> /* The kernel can't use UFFDIO_ZEROPAGE for hugepages */
> if (!mis->postcopy_tmp_zero_page) {
> @@ -906,8 +914,6 @@ int postcopy_place_page_zero(MigrationIncomingState *mis,
> void *host,
> return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page,
> rb);
> }
> -
> - return 0;
> }
Could there be race? E.g.:
ram_load_thread page_fault_thread
----------------- -------------------
if (recv_bitmap_set())
wake()
copy_page()
recv_bitmap_set()
wake()
request_page()
Then the last requested page may never be serviced?
Thanks,
--
Peter Xu
