Re: [PATCH net-next v7 4/9] xen-netback: Introduce TX grant mapping
From: Ian Campbell <hidden>
Date: 2014-03-13 10:17:59
Also in:
lkml
Pulling out this one comment for the attention on the core Xen/Linux maintainers. On Thu, 2014-03-06 at 21:48 +0000, Zoltan Kiss wrote: [...]
quoted hunk ↗ jump to hunk
@@ -343,8 +347,26 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, vif->pending_prod = MAX_PENDING_REQS; for (i = 0; i < MAX_PENDING_REQS; i++) vif->pending_ring[i] = i; - for (i = 0; i < MAX_PENDING_REQS; i++) - vif->mmap_pages[i] = NULL; + spin_lock_init(&vif->callback_lock); + spin_lock_init(&vif->response_lock); + /* If ballooning is disabled, this will consume real memory, so you + * better enable it. The long term solution would be to use just a + * bunch of valid page descriptors, without dependency on ballooning + */
I wonder if we ought to enforce this via Kconfig? i.e. making CONFIG_XEN_BACKEND (or the individual backends) depend on BALLOON (or select?) or by making CONFIG_XEN_BALLOON non-optional etc. IIRC David V was looking into a solution involving auto hotplugging a new region to use for this case, but then I guess CONFIG_XEN_BALLOON_MEMORY_HOTPLUG would equally need to be enabled.
+ err = alloc_xenballooned_pages(MAX_PENDING_REQS, + vif->mmap_pages, + false);
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