RE: [PATCH 4/7] migration/multifd: Add UADK initialization

[Shameerali Kolothum Thodi]

> -----Original Message-----
> From: Fabiano Rosas <farosas@suse.de>
> Sent: Wednesday, June 5, 2024 3:58 PM
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>;
> peterx@redhat.com; yuan1.liu@intel.com
> Cc: qemu-devel@nongnu.org; Linuxarm <linuxarm@huawei.com>; linwenkai
> (C) <linwenkai6@hisilicon.com>; zhangfei.gao@linaro.org; huangchenghai
> <huangchenghai2@huawei.com>
> Subject: Re: [PATCH 4/7] migration/multifd: Add UADK initialization
> 
> Shameer Kolothum via <qemu-devel@nongnu.org> writes:
> 
> > Initialize UADK session and allocate buffers required. The actual
> > compression/decompression will only be done in a subsequent patch.
> >
> > Signed-off-by: Shameer Kolothum
> <shameerali.kolothum.thodi@huawei.com>
> > ---
> >  migration/multifd-uadk.c | 207
> ++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 206 insertions(+), 1 deletion(-)
> >
> > diff --git a/migration/multifd-uadk.c b/migration/multifd-uadk.c
> > index c2bb07535b..3172e4d5ca 100644
> > --- a/migration/multifd-uadk.c
> > +++ b/migration/multifd-uadk.c
> > @@ -12,9 +12,214 @@
> >
> >  #include "qemu/osdep.h"
> >  #include "qemu/module.h"
> > +#include "qapi/error.h"
> > +#include "migration.h"
> > +#include "multifd.h"
> > +#include "options.h"
> > +#include "uadk/wd_comp.h"
> > +#include "uadk/wd_sched.h"
> > +
> > +struct wd_data {
> > +    handle_t handle;
> > +    uint8_t *buf;
> > +    uint32_t *buf_hdr;
> > +};
> > +
> > +static bool uadk_hw_initialised(void)
> 
> The first time this is called it will actually do the initialization,
> no? If so, it should be uadk_hw_init().

Ok. Makes sense.

> 
> > +{
> > +    char alg[] = "zlib";
> > +    int ret;
> > +
> > +    ret = wd_comp_init2(alg, SCHED_POLICY_RR, TASK_HW);
> > +    if (ret && ret != -WD_EEXIST) {
> > +        return false;
> > +    } else {
> > +        return true;
> > +    }
> > +}
> > +
> > +static struct wd_data *multifd_uadk_init_sess(uint32_t count,
> > +                                              uint32_t page_size,
> > +                                              bool compress, Error **errp)
> > +{
> > +    struct wd_comp_sess_setup ss = {0};
> > +    struct sched_params param = {0};
> > +    uint32_t size = count * page_size;
> > +    struct wd_data *wd;
> > +
> > +    if (!uadk_hw_initialised()) {
> > +        error_setg(errp, "multifd: UADK hardware not available");
> 
> Does the lib provide a software fallback path that we could use like QPL
> does?

Unfortunately not. That is why I added patch #6 where we will just send
raw data to take care the CI test.

> 
> > +        return NULL;
> > +    }
> > +
> > +    wd = g_new0(struct wd_data, 1);
> > +    ss.alg_type = WD_ZLIB;
> > +    if (compress) {
> > +        ss.op_type = WD_DIR_COMPRESS;
> > +        /* Add an additional page for handling output > input */
> > +        size += page_size;
> > +    } else {
> > +        ss.op_type = WD_DIR_DECOMPRESS;
> > +    }
> > +    param.type = ss.op_type;
> > +    ss.sched_param = &param;
> 
> What about window size and compression level? Don't we need to set them
> here? What do they default to?

Level 1 and 4K. I will add a comment here.
 
> > +
> > +    wd->handle = wd_comp_alloc_sess(&ss);
> > +    if (!wd->handle) {
> > +        error_setg(errp, "multifd: failed wd_comp_alloc_sess");
> > +        goto out;
> > +    }
> > +
> > +    wd->buf = g_try_malloc(size);
> > +    if (!wd->buf) {
> > +        error_setg(errp, "multifd: out of mem for uadk buf");
> > +        goto out_free_sess;
> > +    }
> > +    wd->buf_hdr = g_new0(uint32_t, count);
> > +    return wd;
> > +
> > +out_free_sess:
> > +    wd_comp_free_sess(wd->handle);
> > +out:
> > +    wd_comp_uninit2();
> > +    g_free(wd);
> > +    return NULL;
> > +}
> > +
> > +static void multifd_uadk_uninit_sess(struct wd_data *wd)
> > +{
> > +    wd_comp_free_sess(wd->handle);
> > +    wd_comp_uninit2();
> > +    g_free(wd->buf);
> > +    g_free(wd->buf_hdr);
> > +    g_free(wd);
> > +}
> > +
> > +/**
> > + * multifd_uadk_send_setup: setup send side
> > + *
> > + * Returns 0 for success or -1 for error
> > + *
> > + * @p: Params for the channel that we are using
> > + * @errp: pointer to an error
> > + */
> > +static int multifd_uadk_send_setup(MultiFDSendParams *p, Error **errp)
> > +{
> > +    struct wd_data *wd;
> > +
> > +    wd = multifd_uadk_init_sess(p->page_count, p->page_size, true, errp);
> > +    if (!wd) {
> > +        return -1;
> > +    }
> > +
> > +    p->compress_data = wd;
> > +    assert(p->iov == NULL);
> > +    /*
> > +     * Each page will be compressed independently and sent using an IOV.
> The
> > +     * additional two IOVs are used to store packet header and compressed
> data
> > +     * length
> > +     */
> > +
> > +    p->iov = g_new0(struct iovec, p->page_count + 2);
> > +    return 0;
> > +}
> > +
> > +/**
> > + * multifd_uadk_send_cleanup: cleanup send side
> > + *
> > + * Close the channel and return memory.
> > + *
> > + * @p: Params for the channel that we are using
> > + * @errp: pointer to an error
> > + */
> > +static void multifd_uadk_send_cleanup(MultiFDSendParams *p, Error
> **errp)
> > +{
> > +    struct wd_data *wd = p->compress_data;
> > +
> > +    multifd_uadk_uninit_sess(wd);
> > +    p->compress_data = NULL;
> > +}
> > +
> > +/**
> > + * multifd_uadk_send_prepare: prepare data to be able to send
> > + *
> > + * Create a compressed buffer with all the pages that we are going to
> > + * send.
> > + *
> > + * Returns 0 for success or -1 for error
> > + *
> > + * @p: Params for the channel that we are using
> > + * @errp: pointer to an error
> > + */
> > +static int multifd_uadk_send_prepare(MultiFDSendParams *p, Error
> **errp)
> > +{
> > +    return -1;
> > +}
> > +
> > +/**
> > + * multifd_uadk_recv_setup: setup receive side
> > + *
> > + * Create the compressed channel and buffer.
> > + *
> > + * Returns 0 for success or -1 for error
> > + *
> > + * @p: Params for the channel that we are using
> > + * @errp: pointer to an error
> > + */
> > +static int multifd_uadk_recv_setup(MultiFDRecvParams *p, Error **errp)
> > +{
> > +    struct wd_data *wd;
> > +
> > +    wd = multifd_uadk_init_sess(p->page_count, p->page_size, false, errp);
> > +    if (!wd) {
> > +        return -1;
> > +    }
> > +    p->compress_data = wd;
> > +    return 0;
> > +}
> > +
> > +/**
> > + * multifd_uadk_recv_cleanup: setup receive side
> > + *
> > + * For no compression this function does nothing.
> 
> This line makes no sense here.

Ok.

Thanks,
Shameer