* [Qemu-devel] [PULL 1/2] hbitmap: Add hbitmap_is_serializable()
2017-01-26 2:48 [Qemu-devel] [PULL 0/2] HBitmap patches Fam Zheng
@ 2017-01-26 2:48 ` Fam Zheng
2017-01-26 2:48 ` [Qemu-devel] [PULL 2/2] test-hbitmap: Add hbitmap_is_serializable() calls Fam Zheng
2017-01-27 11:52 ` [Qemu-devel] [PULL 0/2] HBitmap patches Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Fam Zheng @ 2017-01-26 2:48 UTC (permalink / raw)
To: qemu-devel; +Cc: Peter Maydell
From: Max Reitz <mreitz@redhat.com>
Bitmaps with a granularity of 58 or above can be neither serialized nor
deserialized (see the comment in the function added in this series for
an explanation). This patch adds a function so that we can check whether
a bitmap actually can be (de-)serialized at all, thus avoiding failing
the necessary assertion in hbitmap_serialization_granularity().
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20161115225746.3590-2-mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
include/qemu/hbitmap.h | 13 +++++++++++++
util/hbitmap.c | 22 +++++++++++++++++++---
2 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index eb46475..9239fe5 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -146,6 +146,19 @@ void hbitmap_reset_all(HBitmap *hb);
bool hbitmap_get(const HBitmap *hb, uint64_t item);
/**
+ * hbitmap_is_serializable:
+ * @hb: HBitmap which should be (de-)serialized.
+ *
+ * Returns whether the bitmap can actually be (de-)serialized. Other
+ * (de-)serialization functions may only be invoked if this function returns
+ * true.
+ *
+ * Calling (de-)serialization functions does not affect a bitmap's
+ * (de-)serializability.
+ */
+bool hbitmap_is_serializable(const HBitmap *hb);
+
+/**
* hbitmap_serialization_granularity:
* @hb: HBitmap to operate on.
*
diff --git a/util/hbitmap.c b/util/hbitmap.c
index 9f691b7..35088e1 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -387,6 +387,24 @@ void hbitmap_reset_all(HBitmap *hb)
hb->count = 0;
}
+bool hbitmap_is_serializable(const HBitmap *hb)
+{
+ /* Every serialized chunk must be aligned to 64 bits so that endianness
+ * requirements can be fulfilled on both 64 bit and 32 bit hosts.
+ * We have hbitmap_serialization_granularity() which converts this
+ * alignment requirement from bitmap bits to items covered (e.g. sectors).
+ * That value is:
+ * 64 << hb->granularity
+ * Since this value must not exceed UINT64_MAX, hb->granularity must be
+ * less than 58 (== 64 - 6, where 6 is ld(64), i.e. 1 << 6 == 64).
+ *
+ * In order for hbitmap_serialization_granularity() to always return a
+ * meaningful value, bitmaps that are to be serialized must have a
+ * granularity of less than 58. */
+
+ return hb->granularity < 58;
+}
+
bool hbitmap_get(const HBitmap *hb, uint64_t item)
{
/* Compute position and bit in the last layer. */
@@ -399,9 +417,7 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item)
uint64_t hbitmap_serialization_granularity(const HBitmap *hb)
{
- /* Must hold true so that the shift below is defined
- * (ld(64) == 6, i.e. 1 << 6 == 64) */
- assert(hb->granularity < 64 - 6);
+ assert(hbitmap_is_serializable(hb));
/* Require at least 64 bit granularity to be safe on both 64 bit and 32 bit
* hosts. */
--
2.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread* [Qemu-devel] [PULL 2/2] test-hbitmap: Add hbitmap_is_serializable() calls
2017-01-26 2:48 [Qemu-devel] [PULL 0/2] HBitmap patches Fam Zheng
2017-01-26 2:48 ` [Qemu-devel] [PULL 1/2] hbitmap: Add hbitmap_is_serializable() Fam Zheng
@ 2017-01-26 2:48 ` Fam Zheng
2017-01-27 11:52 ` [Qemu-devel] [PULL 0/2] HBitmap patches Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Fam Zheng @ 2017-01-26 2:48 UTC (permalink / raw)
To: qemu-devel; +Cc: Peter Maydell
From: Max Reitz <mreitz@redhat.com>
Add calls to hbitmap_is_serializable() (asserting that it returns true)
where necessary (i.e. before every series of (de-)serialization function
invocations).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20161115225746.3590-3-mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
tests/test-hbitmap.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index 9b7495c..23773d2 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -744,6 +744,8 @@ static void test_hbitmap_serialize_granularity(TestHBitmapData *data,
int r;
hbitmap_test_init(data, L3 * 2, 3);
+ g_assert(hbitmap_is_serializable(data->hb));
+
r = hbitmap_serialization_granularity(data->hb);
g_assert_cmpint(r, ==, 64 << 3);
}
@@ -768,6 +770,8 @@ static void hbitmap_test_serialize_range(TestHBitmapData *data,
if (count) {
hbitmap_set(data->hb, pos, count);
}
+
+ g_assert(hbitmap_is_serializable(data->hb));
hbitmap_serialize_part(data->hb, buf, 0, data->size);
/* Serialized buffer is inherently LE, convert it back manually to test */
@@ -788,6 +792,8 @@ static void hbitmap_test_serialize_range(TestHBitmapData *data,
memset(buf, 0, buf_size);
hbitmap_serialize_part(data->hb, buf, 0, data->size);
hbitmap_reset_all(data->hb);
+
+ g_assert(hbitmap_is_serializable(data->hb));
hbitmap_deserialize_part(data->hb, buf, 0, data->size, true);
for (i = 0; i < data->size; i++) {
@@ -810,6 +816,7 @@ static void test_hbitmap_serialize_basic(TestHBitmapData *data,
int num_positions = sizeof(positions) / sizeof(positions[0]);
hbitmap_test_init(data, L3, 0);
+ g_assert(hbitmap_is_serializable(data->hb));
buf_size = hbitmap_serialization_size(data->hb, 0, data->size);
buf = g_malloc0(buf_size);
@@ -841,6 +848,8 @@ static void test_hbitmap_serialize_part(TestHBitmapData *data,
hbitmap_set(data->hb, positions[i], 1);
}
+ g_assert(hbitmap_is_serializable(data->hb));
+
for (i = 0; i < data->size; i += buf_size) {
unsigned long *el = (unsigned long *)buf;
hbitmap_serialize_part(data->hb, buf, i, buf_size);
@@ -879,6 +888,8 @@ static void test_hbitmap_serialize_zeroes(TestHBitmapData *data,
hbitmap_set(data->hb, positions[i], L1);
}
+ g_assert(hbitmap_is_serializable(data->hb));
+
for (i = 0; i < num_positions; i++) {
hbitmap_deserialize_zeroes(data->hb, positions[i], min_l1, true);
hbitmap_iter_init(&iter, data->hb, 0);
--
2.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread