netdev - virtio_net: remove recv refill work?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1299791038.25664.213.camel@localhost.localdomain>
Date:	Thu, 10 Mar 2011 13:03:58 -0800
From:	Shirley Ma <mashirle@...ibm.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	kvm@...r.kernel.org, netdev@...r.kernel.org,
	"Michael S. Tsirkin" <mst@...hat.com>
Subject: virtio_net: remove recv refill work?

Hello Rusty,

What's the reason to use refill work in receiving path? 

static void refill_work(struct work_struct *work)
{
        struct virtnet_info *vi;
        bool still_empty;

        vi = container_of(work, struct virtnet_info, refill.work);
        napi_disable(&vi->napi);
        still_empty = !try_fill_recv(vi, GFP_KERNEL);
        napi_enable(&vi->napi);

        /* In theory, this can happen: if we don't get any buffers in
         * we will *never* try to fill again. */
        if (still_empty)
                schedule_delayed_work(&vi->refill, HZ/2);
}

It looks more expensive than only refilling the buffers in recv path. It
could cause more guest exits, maybe more RX interrupts. Can we move the
refill work in recv path only?

If we can remove it, I will run some test to compare the difference with
the change.

Thanks
Shirley



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html