diff mbox series

[v1,15/29] virito-mem: document Sub Block Mode (SBM)

Message ID 20201012125323.17509-16-david@redhat.com (mailing list archive)
State New, archived
Headers show
Series virtio-mem: Big Block Mode (BBM) | expand

Commit Message

David Hildenbrand Oct. 12, 2020, 12:53 p.m. UTC
Let's add some documentation for the current mode - Sub Block Mode (SBM) -
to prepare for a new mode - Big Block Mode (BBM).

Follow-up patches will properly factor out the existing Sub Block Mode
(SBM) and implement Device Block Mode (DBM).

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/virtio/virtio_mem.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Comments

David Hildenbrand Oct. 15, 2020, 9:33 a.m. UTC | #1
On 12.10.20 14:53, David Hildenbrand wrote:
> Let's add some documentation for the current mode - Sub Block Mode (SBM) -
> to prepare for a new mode - Big Block Mode (BBM).
> 
> Follow-up patches will properly factor out the existing Sub Block Mode
> (SBM) and implement Device Block Mode (DBM).

s/Device Block Mode (DBM)/Big Block Mode (BBM)/
Wei Yang Oct. 16, 2020, 8:03 a.m. UTC | #2
On Mon, Oct 12, 2020 at 02:53:09PM +0200, David Hildenbrand wrote:
>Let's add some documentation for the current mode - Sub Block Mode (SBM) -
>to prepare for a new mode - Big Block Mode (BBM).
>
>Follow-up patches will properly factor out the existing Sub Block Mode
>(SBM) and implement Device Block Mode (DBM).
>
>Cc: "Michael S. Tsirkin" <mst@redhat.com>
>Cc: Jason Wang <jasowang@redhat.com>
>Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
>Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>

>---
> drivers/virtio/virtio_mem.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
>diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
>index faeb759687fe..fd8685673fe4 100644
>--- a/drivers/virtio/virtio_mem.c
>+++ b/drivers/virtio/virtio_mem.c
>@@ -27,6 +27,21 @@ static bool unplug_online = true;
> module_param(unplug_online, bool, 0644);
> MODULE_PARM_DESC(unplug_online, "Try to unplug online memory");
> 
>+/*
>+ * virtio-mem currently supports the following modes of operation:
>+ *
>+ * * Sub Block Mode (SBM): A Linux memory block spans 1..X subblocks (SB). The
>+ *   size of a Sub Block (SB) is determined based on the device block size, the
>+ *   pageblock size, and the maximum allocation granularity of the buddy.
>+ *   Subblocks within a Linux memory block might either be plugged or unplugged.
>+ *   Memory is added/removed to Linux MM in Linux memory block granularity.
>+ *
>+ * User space / core MM (auto onlining) is responsible for onlining added
>+ * Linux memory blocks - and for selecting a zone. Linux Memory Blocks are
>+ * always onlined separately, and all memory within a Linux memory block is
>+ * onlined to the same zone - virtio-mem relies on this behavior.
>+ */
>+
> enum virtio_mem_mb_state {
> 	/* Unplugged, not added to Linux. Can be reused later. */
> 	VIRTIO_MEM_MB_STATE_UNUSED = 0,
>-- 
>2.26.2
Pankaj Gupta Oct. 20, 2020, 9:38 a.m. UTC | #3
> > Let's add some documentation for the current mode - Sub Block Mode (SBM) -
> > to prepare for a new mode - Big Block Mode (BBM).
> >
> > Follow-up patches will properly factor out the existing Sub Block Mode
> > (SBM) and implement Device Block Mode (DBM).
>
> s/Device Block Mode (DBM)/Big Block Mode (BBM)/
>

Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
diff mbox series

Patch

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index faeb759687fe..fd8685673fe4 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -27,6 +27,21 @@  static bool unplug_online = true;
 module_param(unplug_online, bool, 0644);
 MODULE_PARM_DESC(unplug_online, "Try to unplug online memory");
 
+/*
+ * virtio-mem currently supports the following modes of operation:
+ *
+ * * Sub Block Mode (SBM): A Linux memory block spans 1..X subblocks (SB). The
+ *   size of a Sub Block (SB) is determined based on the device block size, the
+ *   pageblock size, and the maximum allocation granularity of the buddy.
+ *   Subblocks within a Linux memory block might either be plugged or unplugged.
+ *   Memory is added/removed to Linux MM in Linux memory block granularity.
+ *
+ * User space / core MM (auto onlining) is responsible for onlining added
+ * Linux memory blocks - and for selecting a zone. Linux Memory Blocks are
+ * always onlined separately, and all memory within a Linux memory block is
+ * onlined to the same zone - virtio-mem relies on this behavior.
+ */
+
 enum virtio_mem_mb_state {
 	/* Unplugged, not added to Linux. Can be reused later. */
 	VIRTIO_MEM_MB_STATE_UNUSED = 0,