From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: Marek Kedzierski <mkedzier@redhat.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>,
David Hildenbrand <david@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Alex Williamson <alex.williamson@redhat.com>,
Peter Xu <peterx@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Auger Eric <eric.auger@redhat.com>,
Pankaj Gupta <pankaj.gupta@cloud.ionos.com>,
teawater <teawaterz@linux.alibaba.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Igor Mammedov <imammedo@redhat.com>
Subject: [PATCH v4 09/11] softmmu/physmem: Extend ram_block_discard_(require|disable) by two discard types
Date: Thu, 7 Jan 2021 14:34:21 +0100 [thread overview]
Message-ID: <20210107133423.44964-10-david@redhat.com> (raw)
In-Reply-To: <20210107133423.44964-1-david@redhat.com>
We want to separate the two cases whereby we discard ram
- uncoordinated: e.g., virito-balloon
- coordinated: e.g., virtio-mem coordinated via the RamDiscardMgr
Reviewed-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/exec/memory.h | 18 +++++++++++++--
softmmu/physmem.c | 54 ++++++++++++++++++++++++++++++++++++++-----
2 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 67d9f1f3a7..11832cce3c 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -2808,6 +2808,12 @@ static inline MemOp devend_memop(enum device_endian end)
*/
int ram_block_discard_disable(bool state);
+/*
+ * See ram_block_discard_disable(): only disable uncoordinated discards,
+ * keeping coordinated discards (via the RamDiscardMgr) enabled.
+ */
+int ram_block_uncoordinated_discard_disable(bool state);
+
/*
* Inhibit technologies that disable discarding of pages in RAM blocks.
*
@@ -2817,12 +2823,20 @@ int ram_block_discard_disable(bool state);
int ram_block_discard_require(bool state);
/*
- * Test if discarding of memory in ram blocks is disabled.
+ * See ram_block_discard_require(): only inhibit technologies that disable
+ * uncoordinated discarding of pages in RAM blocks, allowing co-existance with
+ * technologies that only inhibit uncoordinated discards (via the
+ * RamDiscardMgr).
+ */
+int ram_block_coordinated_discard_require(bool state);
+
+/*
+ * Test if any discarding of memory in ram blocks is disabled.
*/
bool ram_block_discard_is_disabled(void);
/*
- * Test if discarding of memory in ram blocks is required to work reliably.
+ * Test if any discarding of memory in ram blocks is required to work reliably.
*/
bool ram_block_discard_is_required(void);
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index dc61335b60..2e8512aa26 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -3660,8 +3660,14 @@ void mtree_print_dispatch(AddressSpaceDispatch *d, MemoryRegion *root)
}
}
+/* Require any discards to work. */
static unsigned int ram_block_discard_requirers;
+/* Require only coordinated discards to work. */
+static unsigned int ram_block_coordinated_discard_requirers;
+/* Disable any discards. */
static unsigned int ram_block_discard_disablers;
+/* Disable only uncoordinated discards. */
+static unsigned int ram_block_uncoordinated_discard_disablers;
static QemuMutex ram_block_discard_disable_mutex;
static void ram_block_discard_disable_mutex_lock(void)
@@ -3687,10 +3693,27 @@ int ram_block_discard_disable(bool state)
ram_block_discard_disable_mutex_lock();
if (!state) {
ram_block_discard_disablers--;
- } else if (!ram_block_discard_requirers) {
- ram_block_discard_disablers++;
+ } else if (ram_block_discard_requirers ||
+ ram_block_coordinated_discard_requirers) {
+ ret = -EBUSY;
} else {
+ ram_block_discard_disablers++;
+ }
+ ram_block_discard_disable_mutex_unlock();
+ return ret;
+}
+
+int ram_block_uncoordinated_discard_disable(bool state)
+{
+ int ret = 0;
+
+ ram_block_discard_disable_mutex_lock();
+ if (!state) {
+ ram_block_uncoordinated_discard_disablers--;
+ } else if (ram_block_discard_requirers) {
ret = -EBUSY;
+ } else {
+ ram_block_uncoordinated_discard_disablers++;
}
ram_block_discard_disable_mutex_unlock();
return ret;
@@ -3703,10 +3726,27 @@ int ram_block_discard_require(bool state)
ram_block_discard_disable_mutex_lock();
if (!state) {
ram_block_discard_requirers--;
- } else if (!ram_block_discard_disablers) {
- ram_block_discard_requirers++;
+ } else if (ram_block_discard_disablers ||
+ ram_block_uncoordinated_discard_disablers) {
+ ret = -EBUSY;
} else {
+ ram_block_discard_requirers++;
+ }
+ ram_block_discard_disable_mutex_unlock();
+ return ret;
+}
+
+int ram_block_coordinated_discard_require(bool state)
+{
+ int ret = 0;
+
+ ram_block_discard_disable_mutex_lock();
+ if (!state) {
+ ram_block_coordinated_discard_requirers--;
+ } else if (ram_block_discard_disablers) {
ret = -EBUSY;
+ } else {
+ ram_block_coordinated_discard_requirers++;
}
ram_block_discard_disable_mutex_unlock();
return ret;
@@ -3714,10 +3754,12 @@ int ram_block_discard_require(bool state)
bool ram_block_discard_is_disabled(void)
{
- return qatomic_read(&ram_block_discard_disablers);
+ return qatomic_read(&ram_block_discard_disablers) ||
+ qatomic_read(&ram_block_uncoordinated_discard_disablers);
}
bool ram_block_discard_is_required(void)
{
- return qatomic_read(&ram_block_discard_requirers);
+ return qatomic_read(&ram_block_discard_requirers) ||
+ qatomic_read(&ram_block_coordinated_discard_requirers);
}
--
2.29.2
next prev parent reply other threads:[~2021-01-07 13:46 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 13:34 [PATCH v4 00/11] virtio-mem: vfio support David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 01/11] memory: Introduce RamDiscardMgr for RAM memory regions David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 02/11] virtio-mem: Factor out traversing unplugged ranges David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 03/11] virtio-mem: Implement RamDiscardMgr interface David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 04/11] vfio: Support for RamDiscardMgr in the !vIOMMU case David Hildenbrand
2021-01-13 23:27 ` Alex Williamson
2021-01-14 15:54 ` David Hildenbrand
2021-01-14 15:57 ` David Hildenbrand
2021-01-15 10:27 ` David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 05/11] vfio: Query and store the maximum number of possible DMA mappings David Hildenbrand
2021-01-13 23:30 ` Alex Williamson
2021-01-07 13:34 ` [PATCH v4 06/11] vfio: Sanity check maximum number of DMA mappings with RamDiscardMgr David Hildenbrand
2021-01-13 23:34 ` Alex Williamson
2021-01-14 15:59 ` David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 07/11] vfio: Support for RamDiscardMgr in the vIOMMU case David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 08/11] softmmu/physmem: Don't use atomic operations in ram_block_discard_(disable|require) David Hildenbrand
2021-01-07 13:34 ` David Hildenbrand [this message]
2021-01-07 13:34 ` [PATCH v4 10/11] virtio-mem: Require only coordinated discards David Hildenbrand
2021-01-07 13:34 ` [PATCH v4 11/11] vfio: Disable only uncoordinated discards David Hildenbrand
2021-01-13 23:57 ` Alex Williamson
2021-01-14 16:19 ` David Hildenbrand
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