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From: Rusty Russell <rusty@rustcorp.com.au>
To: Linus Torvalds <torvalds@linux-foundation.org>,
        Dave Chinner <david@fromorbit.com>, Jens Axboe <axboe@kernel.dk>,
        Minchan Kim <minchan@kernel.org>,
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        Hugh Dickins <hughd@google.com>, "Michael S. Tsirkin" <mst@redhat.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: virtio ring cleanups, which save stack on older gcc
Date: Thu, 29 May 2014 16:56:41 +0930
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They don't make much difference: the easier fix is use gcc 4.8
which drops stack required across virtio block's virtio_queue_rq
down to that kmalloc in virtio_ring from 528 to 392 bytes.

Still, these (*lightly tested*) patches reduce to 432 bytes,
even for gcc 4.6.4.  Posted here FYI.

Cheers,
Rusty.