Commit 096bf4c8 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Michael S. Tsirkin
Browse files

vhost+postcopy: Helper to send requests to source for shared pages 



Provide a helper to be used by shared waker functions to request
shared pages from the source.
The last_rb pointer is moved into the incoming state since this
helper can update it as well as the main fault thread function.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 905125d0

migration/migration.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ struct MigrationIncomingState { 
    int       userfault_event_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 */

migration/postcopy-ram.c

+29 −3
Original line number Diff line number Diff line
@@ -525,6 +525,32 @@ 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

 * Note: Only for use by shared fault handlers (in fault thread)

 */

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

 */
@@ -535,9 +561,9 @@ 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;
@@ -636,8 +662,8 @@ 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 {

migration/postcopy-ram.h

+3 −0
Original line number Diff line number Diff line
@@ -164,5 +164,8 @@ 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

migration/trace-events

+2 −0
Original line number Diff line number Diff line
@@ -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"