Merge "liblp: Allocate "b" extents in the second half of super." am: 5cd7969177
am: fd93770291
Change-Id: I982ab3f72f958c98f4c0d595ab4c35e893ba306a
diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index da86d75..699b9e7 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -578,6 +578,12 @@
CHECK_NE(sectors_per_block, 0);
CHECK(sectors_needed % sectors_per_block == 0);
+ if (IsABDevice() && !IsRetrofitDevice() && GetPartitionSlotSuffix(partition->name()) == "_b") {
+ // Allocate "a" partitions top-down and "b" partitions bottom-up, to
+ // minimize fragmentation during OTA.
+ free_regions = PrioritizeSecondHalfOfSuper(free_regions);
+ }
+
// Find gaps that we can use for new extents. Note we store new extents in a
// temporary vector, and only commit them if we are guaranteed enough free
// space.
@@ -621,6 +627,40 @@
return true;
}
+std::vector<MetadataBuilder::Interval> MetadataBuilder::PrioritizeSecondHalfOfSuper(
+ const std::vector<Interval>& free_list) {
+ const auto& super = block_devices_[0];
+ uint64_t first_sector = super.first_logical_sector;
+ uint64_t last_sector = super.size / LP_SECTOR_SIZE;
+ uint64_t midpoint = first_sector + (last_sector - first_sector) / 2;
+
+ // Choose an aligned sector for the midpoint. This could lead to one half
+ // being slightly larger than the other, but this will not restrict the
+ // size of partitions (it might lead to one extra extent if "B" overflows).
+ midpoint = AlignSector(super, midpoint);
+
+ std::vector<Interval> first_half;
+ std::vector<Interval> second_half;
+ for (const auto& region : free_list) {
+ // Note: deprioritze if not the main super partition. Even though we
+ // don't call this for retrofit devices, we will allow adding additional
+ // block devices on non-retrofit devices.
+ if (region.device_index != 0 || region.end <= midpoint) {
+ first_half.emplace_back(region);
+ continue;
+ }
+ if (region.start < midpoint && region.end > midpoint) {
+ // Split this into two regions.
+ first_half.emplace_back(region.device_index, region.start, midpoint);
+ second_half.emplace_back(region.device_index, midpoint, region.end);
+ } else {
+ second_half.emplace_back(region);
+ }
+ }
+ second_half.insert(second_half.end(), first_half.begin(), first_half.end());
+ return second_half;
+}
+
void MetadataBuilder::ShrinkPartition(Partition* partition, uint64_t aligned_size) {
partition->ShrinkTo(aligned_size);
}
@@ -930,5 +970,9 @@
return android::base::GetBoolProperty("ro.build.ab_update", false);
}
+bool MetadataBuilder::IsRetrofitDevice() const {
+ return GetBlockDevicePartitionName(block_devices_[0]) != LP_METADATA_DEFAULT_PARTITION_NAME;
+}
+
} // namespace fs_mgr
} // namespace android
diff --git a/fs_mgr/liblp/builder_test.cpp b/fs_mgr/liblp/builder_test.cpp
index 926fe12..7833a25 100644
--- a/fs_mgr/liblp/builder_test.cpp
+++ b/fs_mgr/liblp/builder_test.cpp
@@ -720,3 +720,41 @@
ASSERT_EQ(builder->AddPartition("system", 0), nullptr);
ASSERT_NE(builder->AddPartition("system_a", 0), nullptr);
}
+
+TEST_F(BuilderTest, ABExtents) {
+ BlockDeviceInfo device_info("super", 10_GiB, 768 * 1024, 0, 4096);
+
+ // A and B slots should be allocated from separate halves of the partition,
+ // to mitigate allocating too many extents. (b/120433288)
+ MetadataBuilder::OverrideABForTesting(true);
+ auto builder = MetadataBuilder::New(device_info, 65536, 2);
+ ASSERT_NE(builder, nullptr);
+ Partition* system_a = builder->AddPartition("system_a", 0);
+ ASSERT_NE(system_a, nullptr);
+ Partition* system_b = builder->AddPartition("system_b", 0);
+ ASSERT_NE(system_b, nullptr);
+ ASSERT_TRUE(builder->ResizePartition(system_a, 2_GiB));
+ ASSERT_TRUE(builder->ResizePartition(system_b, 2_GiB));
+
+ builder->RemovePartition("system_a");
+ system_a = builder->AddPartition("system_a", 0);
+ ASSERT_NE(system_a, nullptr);
+ ASSERT_TRUE(builder->ResizePartition(system_a, 3_GiB));
+
+ EXPECT_EQ(system_a->extents().size(), static_cast<size_t>(1));
+ EXPECT_EQ(system_b->extents().size(), static_cast<size_t>(1));
+ ASSERT_TRUE(builder->ResizePartition(system_b, 6_GiB));
+ EXPECT_EQ(system_b->extents().size(), static_cast<size_t>(3));
+
+ unique_ptr<LpMetadata> exported = builder->Export();
+ ASSERT_NE(exported, nullptr);
+ ASSERT_EQ(exported->extents.size(), static_cast<size_t>(4));
+ EXPECT_EQ(exported->extents[0].target_data, 10487808);
+ EXPECT_EQ(exported->extents[0].num_sectors, 4194304);
+ EXPECT_EQ(exported->extents[1].target_data, 14682624);
+ EXPECT_EQ(exported->extents[1].num_sectors, 6288896);
+ EXPECT_EQ(exported->extents[2].target_data, 6292992);
+ EXPECT_EQ(exported->extents[2].num_sectors, 2099712);
+ EXPECT_EQ(exported->extents[3].target_data, 1536);
+ EXPECT_EQ(exported->extents[3].num_sectors, 6291456);
+}
diff --git a/fs_mgr/liblp/include/liblp/builder.h b/fs_mgr/liblp/include/liblp/builder.h
index 4bb38d6..f477b4b 100644
--- a/fs_mgr/liblp/include/liblp/builder.h
+++ b/fs_mgr/liblp/include/liblp/builder.h
@@ -275,6 +275,7 @@
const LpMetadataPartition& source);
bool ImportPartition(const LpMetadata& metadata, const LpMetadataPartition& source);
bool IsABDevice() const;
+ bool IsRetrofitDevice() const;
struct Interval {
uint32_t device_index;
@@ -294,6 +295,7 @@
std::vector<Interval> GetFreeRegions() const;
void ExtentsToFreeList(const std::vector<Interval>& extents,
std::vector<Interval>* free_regions) const;
+ std::vector<Interval> PrioritizeSecondHalfOfSuper(const std::vector<Interval>& free_list);
static bool sABOverrideValue;
static bool sABOverrideSet;