> -----Original Message-----
> From: Fabiano Rosas <faro...@suse.de>
> Sent: Wednesday, March 20, 2024 11:19 PM
> To: Liu, Yuan1 <yuan1....@intel.com>; pet...@redhat.com
> Cc: qemu-devel@nongnu.org; hao.xi...@bytedance.com;
> bryan.zh...@bytedance.com; Liu, Yuan1 <yuan1....@intel.com>; Zou, Nanhai
> <nanhai....@intel.com>
> Subject: Re: [PATCH v5 2/7] migration/multifd: put IOV initialization into
> compression method
>
> Yuan Liu <yuan1....@intel.com> writes:
>
> > Different compression methods may require different numbers of IOVs.
> > Based on streaming compression of zlib and zstd, all pages will be
> > compressed to a data block, so two IOVs are needed for packet header
> > and compressed data block.
> >
> > Signed-off-by: Yuan Liu <yuan1....@intel.com>
> > Reviewed-by: Nanhai Zou <nanhai....@intel.com>
> > ---
> > migration/multifd-zlib.c | 4 ++++
> > migration/multifd-zstd.c | 6 +++++-
> > migration/multifd.c | 8 +++++---
> > 3 files changed, 14 insertions(+), 4 deletions(-)
> >
> > diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
> > index 99821cd4d5..8095ef8e28 100644
> > --- a/migration/multifd-zlib.c
> > +++ b/migration/multifd-zlib.c
> > @@ -70,6 +70,10 @@ static int zlib_send_setup(MultiFDSendParams *p,
> Error **errp)
> > goto err_free_zbuff;
> > }
> > p->compress_data = z;
> > +
> > + assert(p->iov == NULL);
> > + /* For packet header and zlib streaming compression block */
> > + p->iov = g_new0(struct iovec, 2);
> > return 0;
> >
> > err_free_zbuff:
> > diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c
> > index 02112255ad..9c9217794e 100644
> > --- a/migration/multifd-zstd.c
> > +++ b/migration/multifd-zstd.c
> > @@ -52,7 +52,6 @@ static int zstd_send_setup(MultiFDSendParams *p, Error
> **errp)
> > struct zstd_data *z = g_new0(struct zstd_data, 1);
> > int res;
> >
> > - p->compress_data = z;
> > z->zcs = ZSTD_createCStream();
> > if (!z->zcs) {
> > g_free(z);
> > @@ -77,6 +76,11 @@ static int zstd_send_setup(MultiFDSendParams *p,
> Error **errp)
> > error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
> > return -1;
> > }
> > + p->compress_data = z;
> > +
> > + assert(p->iov == NULL);
> > + /* For packet header and zstd streaming compression block */
> > + p->iov = g_new0(struct iovec, 2);
> > return 0;
> > }
> >
> > diff --git a/migration/multifd.c b/migration/multifd.c
> > index 0179422f6d..5155e02ae3 100644
> > --- a/migration/multifd.c
> > +++ b/migration/multifd.c
> > @@ -1181,9 +1181,11 @@ bool multifd_send_setup(void)
> > p->packet = g_malloc0(p->packet_len);
> > p->packet->magic = cpu_to_be32(MULTIFD_MAGIC);
> > p->packet->version = cpu_to_be32(MULTIFD_VERSION);
> > -
> > - /* We need one extra place for the packet header */
> > - p->iov = g_new0(struct iovec, page_count + 1);
> > + /* IOVs are initialized in send_setup of compression method
> */
> > + if (!migrate_multifd_compression()) {
> > + /* We need one extra place for the packet header */
> > + p->iov = g_new0(struct iovec, page_count + 1);
> > + }
>
> This^ should go into nocomp_send_setup:
>
> static int nocomp_send_setup(MultiFDSendParams *p, Error **errp)
> {
> if (migrate_zero_copy_send()) {
> p->write_flags |= QIO_CHANNEL_WRITE_FLAG_ZERO_COPY;
> }
>
> if (multifd_use_packets()) {
> /* We need one extra place for the packet header */
> p->iov = g_new0(struct iovec, p->page_count + 1);
> } else {
> p->iov = g_new0(struct iovec, p->page_count);
> }
>
> return 0;
> }
Yes, this is better, I will fix this in the next version,
thanks for your comments.
> > } else {
> > p->iov = g_new0(struct iovec, page_count);
> > }
