On 03/21/2013 07:37 PM, Juan Quintela wrote: > Orit Wasserman <[email protected]> wrote: >> This will remove an unneeded copy of guest memory pages. >> For the page header and device state we still copy the data to the >> static buffer the other option is to allocate the memory on demand >> which is more expensive. >> >> Signed-off-by: Orit Wasserman <[email protected]> >> --- >> arch_init.c | 2 +- >> savevm.c | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch_init.c b/arch_init.c >> index 98e2bc6..27b53eb 100644 >> --- a/arch_init.c >> +++ b/arch_init.c >> @@ -481,7 +481,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage) >> /* XBZRLE overflow or normal page */ >> if (bytes_sent == -1) { >> bytes_sent = save_block_hdr(f, block, offset, cont, >> RAM_SAVE_FLAG_PAGE); >> - qemu_put_buffer(f, p, TARGET_PAGE_SIZE); >> + qemu_put_buffer_no_copy(f, p, TARGET_PAGE_SIZE); >> bytes_sent += TARGET_PAGE_SIZE; >> acct_info.norm_pages++; >> } > > Once here, shouldn't we also change: > > block-migration.c::blk_send() > > qemu_put_buffer(f, blk->buf, BLOCK_SIZE); > > to nocopy? Sadly no, I looked at the code and I saw the buffer is freed immediately after call blk_send :(. look at mig_save_device_dirty.
Orit > > Again, this can be an additional patch. > > >> diff --git a/savevm.c b/savevm.c >> index fbfb9e3..50e8fb2 100644 >> --- a/savevm.c >> +++ b/savevm.c >> @@ -634,7 +634,7 @@ void qemu_put_buffer_no_copy(QEMUFile *f, const uint8_t >> *buf, int size) >> abort(); >> } >> >> - f->iov[f->iovcnt].iov_base = f->buf + f->buf_index; >> + f->iov[f->iovcnt].iov_base = (uint8_t *)buf; >> f->iov[f->iovcnt++].iov_len = size; > > This bit should be in the previous patch, the error that I pointed? > > Later, Juan. >
