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51b19ebe43
The return code of virtqueue_pop/vring_pop is unused except to check for errors or 0. We can thus easily move allocation inside the functions and just return a pointer to the VirtQueueElement. The advantage is that we will be able to allocate only the space that is needed for the actual size of the s/g list instead of the full VIRTQUEUE_MAX_SIZE items. Currently VirtQueueElement takes about 48K of memory, and this kind of allocation puts a lot of stress on malloc. By cutting the size by two or three orders of magnitude, malloc can use much more efficient algorithms. The patch is pretty large, but changes to each device are testable more or less independently. Splitting it would mostly add churn. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
51 lines
1.9 KiB
C
51 lines
1.9 KiB
C
/* Copyright 2012 Red Hat, Inc. and/or its affiliates
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* Copyright IBM, Corp. 2012
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*
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* Based on Linux 2.6.39 vhost code:
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* Copyright (C) 2009 Red Hat, Inc.
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* Copyright (C) 2006 Rusty Russell IBM Corporation
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*
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* Author: Michael S. Tsirkin <mst@redhat.com>
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* Stefan Hajnoczi <stefanha@redhat.com>
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*
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* Inspiration, some code, and most witty comments come from
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* Documentation/virtual/lguest/lguest.c, by Rusty Russell
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*
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* This work is licensed under the terms of the GNU GPL, version 2.
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*/
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#ifndef VRING_H
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#define VRING_H
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#include "qemu-common.h"
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#include "standard-headers/linux/virtio_ring.h"
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#include "hw/virtio/virtio.h"
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typedef struct {
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MemoryRegion *mr_desc; /* memory region for the vring desc */
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MemoryRegion *mr_avail; /* memory region for the vring avail */
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MemoryRegion *mr_used; /* memory region for the vring used */
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struct vring vr; /* virtqueue vring mapped to host memory */
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uint16_t last_avail_idx; /* last processed avail ring index */
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uint16_t last_used_idx; /* last processed used ring index */
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uint16_t signalled_used; /* EVENT_IDX state */
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bool signalled_used_valid;
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bool broken; /* was there a fatal error? */
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} Vring;
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/* Fail future vring_pop() and vring_push() calls until reset */
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static inline void vring_set_broken(Vring *vring)
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{
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vring->broken = true;
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}
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bool vring_setup(Vring *vring, VirtIODevice *vdev, int n);
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void vring_teardown(Vring *vring, VirtIODevice *vdev, int n);
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void vring_disable_notification(VirtIODevice *vdev, Vring *vring);
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bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);
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bool vring_should_notify(VirtIODevice *vdev, Vring *vring);
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void *vring_pop(VirtIODevice *vdev, Vring *vring, size_t sz);
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void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
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int len);
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#endif /* VRING_H */
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