diff --git a/src/common/column_matrix.h b/src/common/column_matrix.h
index 454b226e6a66..448099e37b0b 100644
--- a/src/common/column_matrix.h
+++ b/src/common/column_matrix.h
@@ -139,12 +139,16 @@ class DenseColumnIter : public Column<BinIdxT> {
 };
 
 /**
- * \brief Column major matrix for gradient index. This matrix contains both dense column
- * and sparse column, the type of the column is controlled by sparse threshold. When the
- * number of missing values in a column is below the threshold it's classified as dense
- * column.
+ * @brief Column major matrix for gradient index on CPU.
+ *
+ *    This matrix contains both dense columns and sparse columns, the type of the column
+ *    is controlled by the sparse threshold parameter. When the number of missing values
+ *    in a column is below the threshold it's classified as dense column.
  */
 class ColumnMatrix {
+  /**
+   * @brief A bit set for indicating whether an element in a dense column is missing.
+   */
   struct MissingIndicator {
     LBitField32 missing;
     RefResourceView<std::uint32_t> storage;
@@ -159,8 +163,9 @@ class ColumnMatrix {
       storage = common::MakeFixedVecWithMalloc(m_size, init ? ~std::uint32_t{0} : std::uint32_t{0});
       InitView();
     }
-    void Clear(typename LBitField32::index_type i) { missing.Clear(i); }
-
+    /** @brief Set the i^th element to be a valid element (instead of missing). */
+    void SetValid(typename LBitField32::index_type i) { missing.Clear(i); }
+    /** @brief assign the storage to the view. */
     void InitView() { missing = LBitField32{Span{storage.data(), storage.size()}}; }
   };
 
@@ -174,7 +179,7 @@ class ColumnMatrix {
       // not thread-safe with bool vector.
       // FIXME(jiamingy): We can directly assign kMissingId to the index to avoid missing
       // flags.
-      missing_.Clear(feature_offsets_[fid] + rid);
+      missing_.SetValid(feature_offsets_[fid] + rid);
     } else {
       ColumnBinT* begin = &local_index[feature_offsets_[fid]];
       begin[num_nonzeros_[fid]] = bin_id - index_base_[fid];
@@ -186,7 +191,9 @@ class ColumnMatrix {
  public:
   using ByteType = bool;
   // get number of features
-  [[nodiscard]] bst_feature_t GetNumFeature() const { return static_cast<bst_feature_t>(type_.size()); }
+  [[nodiscard]] bst_feature_t GetNumFeature() const {
+    return static_cast<bst_feature_t>(type_.size());
+  }
 
   ColumnMatrix() = default;
   ColumnMatrix(GHistIndexMatrix const& gmat, double sparse_threshold) {
@@ -194,7 +201,7 @@ class ColumnMatrix {
   }
 
   /**
-   * \brief Initialize ColumnMatrix from GHistIndexMatrix with reference to the original
+   * @brief Initialize ColumnMatrix from GHistIndexMatrix with reference to the original
    *        SparsePage.
    */
   void InitFromSparse(SparsePage const& page, const GHistIndexMatrix& gmat, double sparse_threshold,
@@ -206,8 +213,8 @@ class ColumnMatrix {
   }
 
   /**
-   * \brief Initialize ColumnMatrix from GHistIndexMatrix without reference to actual
-   * data.
+   * @brief Initialize ColumnMatrix from GHistIndexMatrix without reference to actual
+   *        data.
    *
    *    This function requires a binary search for each bin to get back the feature index
    *    for those bins.
diff --git a/src/common/io.cc b/src/common/io.cc
index 90812d44a40d..d00f54b64e27 100644
--- a/src/common/io.cc
+++ b/src/common/io.cc
@@ -200,6 +200,9 @@ std::string FileExtension(std::string fname, bool lower) {
   }
 }
 
+// For some reason, NVCC 12.1 marks the function deleted if we expose it in the header.
+ResourceHandler::~ResourceHandler() noexcept(false) = default;
+
 struct MMAPFile {
 #if defined(xgboost_IS_WIN)
   HANDLE fd{INVALID_HANDLE_VALUE};
diff --git a/src/common/io.h b/src/common/io.h
index c3bd5d641b79..c6adff8ddcc4 100644
--- a/src/common/io.h
+++ b/src/common/io.h
@@ -10,9 +10,11 @@
 #include <dmlc/io.h>
 #include <rabit/rabit.h>
 
-#include <cstddef>  // for byte, size_t
+#include <algorithm>  // for min
+#include <cstddef>    // for byte, size_t
 #include <cstring>
 #include <fstream>
+#include <limits>   // for numeric_limits
 #include <memory>   // for unique_ptr
 #include <string>   // for string
 #include <utility>  // for move
@@ -145,7 +147,7 @@ class ResourceHandler {
 
   [[nodiscard]] virtual std::size_t Size() const = 0;
   // Allow exceptions for cleaning up resource.
-  virtual ~ResourceHandler() noexcept(false){};
+  virtual ~ResourceHandler() noexcept(false);
 
   ResourceHandler() = default;
   // Use shared_ptr to manage a pool like resource handler. All copy and assignment