Commit 6629890d authored by Wei Yang's avatar Wei Yang Committed by Dr. David Alan Gilbert
Browse files

migration/postcopy: map large zero page in postcopy_ram_incoming_setup() 



postcopy_ram_incoming_setup() and postcopy_ram_incoming_cleanup() are
counterpart. It is reasonable to map/unmap large zero page in these two
functions respectively.

Signed-off-by: default avatarWei Yang <richardw.yang@linux.intel.com>
Message-Id: <20191005135021.21721-3-richardw.yang@linux.intel.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
parent 3414322a

migration/postcopy-ram.c

+17 −17
Original line number Diff line number Diff line
@@ -1144,6 +1144,22 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis) 
        return -1;

    }



    /*

     * Map large zero page when kernel can't use UFFDIO_ZEROPAGE for hugepages

     */

    mis->postcopy_tmp_zero_page = mmap(NULL, mis->largest_page_size,

                                       PROT_READ | PROT_WRITE,

                                       MAP_PRIVATE | MAP_ANONYMOUS,

                                       -1, 0);

    if (mis->postcopy_tmp_zero_page == MAP_FAILED) {

        int e = errno;

        mis->postcopy_tmp_zero_page = NULL;

        error_report("%s: Failed to map large zero page %s",

                     __func__, strerror(e));

        return -e;

    }

    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.
@@ -1250,23 +1266,7 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, 
                                           qemu_ram_block_host_offset(rb,

                                                                      host));

    } else {

        /* The kernel can't use UFFDIO_ZEROPAGE for hugepages */

        if (!mis->postcopy_tmp_zero_page) {

            mis->postcopy_tmp_zero_page = mmap(NULL, mis->largest_page_size,

                                               PROT_READ | PROT_WRITE,

                                               MAP_PRIVATE | MAP_ANONYMOUS,

                                               -1, 0);

            if (mis->postcopy_tmp_zero_page == MAP_FAILED) {

                int e = errno;

                mis->postcopy_tmp_zero_page = NULL;

                error_report("%s: %s mapping large zero page",

                             __func__, strerror(e));

                return -e;

            }

            memset(mis->postcopy_tmp_zero_page, '\0', mis->largest_page_size);

        }

        return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page,

                                   rb);

        return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page, rb);

    }

}