refactor: Use uint256 directly as key instead of void pointer (#6313)

This change replaces `void const*` by `uint256 const&` for database fetches.

Object hashes are expressed using the `uint256` data type, and are converted to `void *` when calling the `fetch` or `fetchBatch` functions. However, in these fetch functions they are converted back to `uint256`, making the conversion process unnecessary. In a few cases the underlying pointer is needed, but that can then be easy obtained via `[hash variable].data()`.

.github/workflows/reusable-build-test-config.yml

@@ -101,7 +101,7 @@ jobs:
     steps:
       - name: Cleanup workspace (macOS and Windows)
         if: ${{ runner.os == 'macOS' || runner.os == 'Windows' }}
-        uses: XRPLF/actions/cleanup-workspace@cf0433aa74563aead044a1e395610c96d65a37cf
+        uses: XRPLF/actions/cleanup-workspace@c7d9ce5ebb03c752a354889ecd870cadfc2b1cd4
 
       - name: Checkout repository
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

.github/workflows/upload-conan-deps.yml

@@ -64,7 +64,7 @@ jobs:
     steps:
       - name: Cleanup workspace (macOS and Windows)
         if: ${{ runner.os == 'macOS' || runner.os == 'Windows' }}
-        uses: XRPLF/actions/cleanup-workspace@cf0433aa74563aead044a1e395610c96d65a37cf
+        uses: XRPLF/actions/cleanup-workspace@c7d9ce5ebb03c752a354889ecd870cadfc2b1cd4
 
       - name: Checkout repository
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

include/xrpl/basics/MallocTrim.h

@@ -0,0 +1,73 @@
+#pragma once
+
+#include <xrpl/beast/utility/Journal.h>
+
+#include <chrono>
+#include <cstdint>
+#include <string_view>
+
+namespace xrpl {
+
+// cSpell:ignore ptmalloc
+
+// -----------------------------------------------------------------------------
+// Allocator interaction note:
+// - This facility invokes glibc's malloc_trim(0) on Linux/glibc to request that
+//   ptmalloc return free heap pages to the OS.
+// - If an alternative allocator (e.g. jemalloc or tcmalloc) is linked or
+//   preloaded (LD_PRELOAD), calling glibc's malloc_trim typically has no effect
+//   on the *active* heap. The call is harmless but may not reclaim memory
+//   because those allocators manage their own arenas.
+// - Only glibc sbrk/arena space is eligible for trimming; large mmap-backed
+//   allocations are usually returned to the OS on free regardless of trimming.
+// - Call at known reclamation points (e.g., after cache sweeps / online delete)
+//   and consider rate limiting to avoid churn.
+// -----------------------------------------------------------------------------
+
+struct MallocTrimReport
+{
+    bool supported{false};
+    int trimResult{-1};
+    std::int64_t rssBeforeKB{-1};
+    std::int64_t rssAfterKB{-1};
+    std::chrono::microseconds durationUs{-1};
+    std::int64_t minfltDelta{-1};
+    std::int64_t majfltDelta{-1};
+
+    [[nodiscard]] std::int64_t
+    deltaKB() const noexcept
+    {
+        if (rssBeforeKB < 0 || rssAfterKB < 0)
+            return 0;
+        return rssAfterKB - rssBeforeKB;
+    }
+};
+
+/**
+ * @brief Attempt to return freed memory to the operating system.
+ *
+ * On Linux with glibc malloc, this issues ::malloc_trim(0), which may release
+ * free space from ptmalloc arenas back to the kernel. On other platforms, or if
+ * a different allocator is in use, this function is a no-op and the report will
+ * indicate that trimming is unsupported or had no effect.
+ *
+ * @param tag     Identifier for logging/debugging purposes.
+ * @param journal Journal for diagnostic logging.
+ * @return Report containing before/after metrics and the trim result.
+ *
+ * @note If an alternative allocator (jemalloc/tcmalloc) is linked or preloaded,
+ *       calling glibc's malloc_trim may have no effect on the active heap. The
+ *       call is harmless but typically does not reclaim memory under those
+ *       allocators.
+ *
+ * @note Only memory served from glibc's sbrk/arena heaps is eligible for trim.
+ *       Large allocations satisfied via mmap are usually returned on free
+ *       independently of trimming.
+ *
+ * @note Intended for use after operations that free significant memory (e.g.,
+ *       cache sweeps, ledger cleanup, online delete). Consider rate limiting.
+ */
+MallocTrimReport
+mallocTrim(std::string_view tag, beast::Journal journal);
+
+}  // namespace xrpl

include/xrpl/nodestore/Backend.h

@@ -77,16 +77,16 @@ public:
         If the object is not found or an error is encountered, the
         result will indicate the condition.
         @note This will be called concurrently.
-        @param key A pointer to the key data.
+        @param hash The hash of the object.
         @param pObject [out] The created object if successful.
         @return The result of the operation.
     */
     virtual Status
-    fetch(void const* key, std::shared_ptr<NodeObject>* pObject) = 0;
+    fetch(uint256 const& hash, std::shared_ptr<NodeObject>* pObject) = 0;
 
     /** Fetch a batch synchronously. */
     virtual std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
-    fetchBatch(std::vector<uint256 const*> const& hashes) = 0;
+    fetchBatch(std::vector<uint256> const& hashes) = 0;
 
     /** Store a single object.
         Depending on the implementation this may happen immediately

include/xrpl/protocol/detail/features.macro

@@ -15,9 +15,10 @@
 
 // Add new amendments to the top of this list.
 // Keep it sorted in reverse chronological order.
+
 XRPL_FIX   (PermissionedDomainInvariant, Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FIX    (ExpiredNFTokenOfferRemoval, Supported::yes, VoteBehavior::DefaultNo)
-XRPL_FIX    (BatchInnerSigs,             Supported::yes, VoteBehavior::DefaultNo)
+XRPL_FIX    (BatchInnerSigs,             Supported::no, VoteBehavior::DefaultNo)
 XRPL_FEATURE(LendingProtocol,            Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(PermissionDelegationV1_1,   Supported::no,  VoteBehavior::DefaultNo)
 XRPL_FIX    (DirectoryLimit,             Supported::yes, VoteBehavior::DefaultNo)
@@ -31,7 +32,7 @@ XRPL_FEATURE(TokenEscrow,                Supported::yes, VoteBehavior::DefaultNo
 XRPL_FIX    (EnforceNFTokenTrustlineV2,  Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FIX    (AMMv1_3,                    Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(PermissionedDEX,            Supported::yes, VoteBehavior::DefaultNo)
-XRPL_FEATURE(Batch,                      Supported::yes, VoteBehavior::DefaultNo)
+XRPL_FEATURE(Batch,                      Supported::no,  VoteBehavior::DefaultNo)
 XRPL_FEATURE(SingleAssetVault,           Supported::yes,  VoteBehavior::DefaultNo)
 XRPL_FIX    (PayChanCancelAfter,         Supported::yes, VoteBehavior::DefaultNo)
 // Check flags in Credential transactions

src/libxrpl/basics/MallocTrim.cpp

@@ -0,0 +1,157 @@
+#include <xrpl/basics/Log.h>
+#include <xrpl/basics/MallocTrim.h>
+
+#include <boost/predef.h>
+
+#include <chrono>
+#include <cstdint>
+#include <cstdio>
+#include <fstream>
+#include <sstream>
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+#include <sys/resource.h>
+
+#include <malloc.h>
+#include <unistd.h>
+
+// Require RUSAGE_THREAD for thread-scoped page fault tracking
+#ifndef RUSAGE_THREAD
+#error "MallocTrim rusage instrumentation requires RUSAGE_THREAD on Linux/glibc"
+#endif
+
+namespace {
+
+bool
+getRusageThread(struct rusage& ru)
+{
+    return ::getrusage(RUSAGE_THREAD, &ru) == 0;  // LCOV_EXCL_LINE
+}
+
+}  // namespace
+#endif
+
+namespace xrpl {
+
+namespace detail {
+
+// cSpell:ignore statm
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+
+inline int
+mallocTrimWithPad(std::size_t padBytes)
+{
+    return ::malloc_trim(padBytes);
+}
+
+long
+parseStatmRSSkB(std::string const& statm)
+{
+    // /proc/self/statm format: size resident shared text lib data dt
+    // We want the second field (resident) which is in pages
+    std::istringstream iss(statm);
+    long size, resident;
+    if (!(iss >> size >> resident))
+        return -1;
+
+    // Convert pages to KB
+    long const pageSize = ::sysconf(_SC_PAGESIZE);
+    if (pageSize <= 0)
+        return -1;
+
+    return (resident * pageSize) / 1024;
+}
+
+#endif  // __GLIBC__ && BOOST_OS_LINUX
+
+}  // namespace detail
+
+MallocTrimReport
+mallocTrim(std::string_view tag, beast::Journal journal)
+{
+    // LCOV_EXCL_START
+
+    MallocTrimReport report;
+
+#if !(defined(__GLIBC__) && BOOST_OS_LINUX)
+    JLOG(journal.debug()) << "malloc_trim not supported on this platform (tag=" << tag << ")";
+#else
+    // Keep glibc malloc_trim padding at 0 (default): 12h Mainnet tests across 0/256KB/1MB/16MB
+    // showed no clear, consistent benefit from custom padding—0 provided the best overall balance
+    // of RSS reduction and trim-latency stability without adding a tuning surface.
+    constexpr std::size_t TRIM_PAD = 0;
+
+    report.supported = true;
+
+    if (journal.debug())
+    {
+        auto readFile = [](std::string const& path) -> std::string {
+            std::ifstream ifs(path, std::ios::in | std::ios::binary);
+            if (!ifs.is_open())
+                return {};
+
+            // /proc files are often not seekable; read as a stream.
+            std::ostringstream oss;
+            oss << ifs.rdbuf();
+            return oss.str();
+        };
+
+        std::string const tagStr{tag};
+        std::string const statmPath = "/proc/self/statm";
+
+        auto const statmBefore = readFile(statmPath);
+        long const rssBeforeKB = detail::parseStatmRSSkB(statmBefore);
+
+        struct rusage ru0{};
+        bool const have_ru0 = getRusageThread(ru0);
+
+        auto const t0 = std::chrono::steady_clock::now();
+
+        report.trimResult = detail::mallocTrimWithPad(TRIM_PAD);
+
+        auto const t1 = std::chrono::steady_clock::now();
+
+        struct rusage ru1{};
+        bool const have_ru1 = getRusageThread(ru1);
+
+        auto const statmAfter = readFile(statmPath);
+        long const rssAfterKB = detail::parseStatmRSSkB(statmAfter);
+
+        // Populate report fields
+        report.rssBeforeKB = rssBeforeKB;
+        report.rssAfterKB = rssAfterKB;
+        report.durationUs = std::chrono::duration_cast<std::chrono::microseconds>(t1 - t0);
+
+        if (have_ru0 && have_ru1)
+        {
+            report.minfltDelta = ru1.ru_minflt - ru0.ru_minflt;
+            report.majfltDelta = ru1.ru_majflt - ru0.ru_majflt;
+        }
+
+        std::int64_t const deltaKB = (rssBeforeKB < 0 || rssAfterKB < 0)
+            ? 0
+            : (static_cast<std::int64_t>(rssAfterKB) - static_cast<std::int64_t>(rssBeforeKB));
+
+        JLOG(journal.debug()) << "malloc_trim tag=" << tagStr << " result=" << report.trimResult
+                              << " pad=" << TRIM_PAD << " bytes"
+                              << " rss_before=" << rssBeforeKB << "kB"
+                              << " rss_after=" << rssAfterKB << "kB"
+                              << " delta=" << deltaKB << "kB"
+                              << " duration_us=" << report.durationUs.count()
+                              << " minflt_delta=" << report.minfltDelta
+                              << " majflt_delta=" << report.majfltDelta;
+    }
+    else
+    {
+        report.trimResult = detail::mallocTrimWithPad(TRIM_PAD);
+    }
+
+#endif
+
+    return report;
+
+    // LCOV_EXCL_STOP
+}
+
+}  // namespace xrpl

src/libxrpl/nodestore/DatabaseNodeImp.cpp

@@ -33,7 +33,7 @@ DatabaseNodeImp::fetchNodeObject(
 
     try
     {
-        status = backend_->fetch(hash.data(), &nodeObject);
+        status = backend_->fetch(hash, &nodeObject);
     }
     catch (std::exception const& e)
     {
@@ -68,18 +68,10 @@ DatabaseNodeImp::fetchBatch(std::vector<uint256> const& hashes)
     using namespace std::chrono;
     auto const before = steady_clock::now();
 
-    std::vector<uint256 const*> batch{};
-    batch.reserve(hashes.size());
-    for (size_t i = 0; i < hashes.size(); ++i)
-    {
-        auto const& hash = hashes[i];
-        batch.push_back(&hash);
-    }
-
     // Get the node objects that match the hashes from the backend. To protect
     // against the backends returning fewer or more results than expected, the
     // container is resized to the number of hashes.
-    auto results = backend_->fetchBatch(batch).first;
+    auto results = backend_->fetchBatch(hashes).first;
     XRPL_ASSERT(
         results.size() == hashes.size() || results.empty(),
         "number of output objects either matches number of input hashes or is empty");

src/libxrpl/nodestore/DatabaseRotatingImp.cpp

@@ -105,7 +105,7 @@ DatabaseRotatingImp::fetchNodeObject(
         std::shared_ptr<NodeObject> nodeObject;
         try
         {
-            status = backend->fetch(hash.data(), &nodeObject);
+            status = backend->fetch(hash, &nodeObject);
         }
         catch (std::exception const& e)
         {

src/libxrpl/nodestore/backend/MemoryFactory.cpp

@@ -116,10 +116,9 @@ public:
     //--------------------------------------------------------------------------
 
     Status
-    fetch(void const* key, std::shared_ptr<NodeObject>* pObject) override
+    fetch(uint256 const& hash, std::shared_ptr<NodeObject>* pObject) override
     {
         XRPL_ASSERT(db_, "xrpl::NodeStore::MemoryBackend::fetch : non-null database");
-        uint256 const hash(uint256::fromVoid(key));
 
         std::lock_guard _(db_->mutex);
 
@@ -134,14 +133,14 @@ public:
     }
 
     std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
-    fetchBatch(std::vector<uint256 const*> const& hashes) override
+    fetchBatch(std::vector<uint256> const& hashes) override
     {
         std::vector<std::shared_ptr<NodeObject>> results;
         results.reserve(hashes.size());
         for (auto const& h : hashes)
         {
             std::shared_ptr<NodeObject> nObj;
-            Status status = fetch(h->begin(), &nObj);
+            Status status = fetch(h, &nObj);
             if (status != ok)
                 results.push_back({});
             else

src/libxrpl/nodestore/backend/NuDBFactory.cpp

@@ -179,17 +179,17 @@ public:
     }
 
     Status
-    fetch(void const* key, std::shared_ptr<NodeObject>* pno) override
+    fetch(uint256 const& hash, std::shared_ptr<NodeObject>* pno) override
     {
         Status status;
         pno->reset();
         nudb::error_code ec;
         db_.fetch(
-            key,
+            hash.data(),
-            [key, pno, &status](void const* data, std::size_t size) {
+            [&hash, pno, &status](void const* data, std::size_t size) {
                 nudb::detail::buffer bf;
                 auto const result = nodeobject_decompress(data, size, bf);
-                DecodedBlob decoded(key, result.first, result.second);
+                DecodedBlob decoded(hash.data(), result.first, result.second);
                 if (!decoded.wasOk())
                 {
                     status = dataCorrupt;
@@ -207,14 +207,14 @@ public:
     }
 
     std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
-    fetchBatch(std::vector<uint256 const*> const& hashes) override
+    fetchBatch(std::vector<uint256> const& hashes) override
     {
         std::vector<std::shared_ptr<NodeObject>> results;
         results.reserve(hashes.size());
         for (auto const& h : hashes)
         {
             std::shared_ptr<NodeObject> nObj;
-            Status status = fetch(h->begin(), &nObj);
+            Status status = fetch(h, &nObj);
             if (status != ok)
                 results.push_back({});
             else

src/libxrpl/nodestore/backend/NullFactory.cpp

@@ -36,13 +36,13 @@ public:
     }
 
     Status
-    fetch(void const*, std::shared_ptr<NodeObject>*) override
+    fetch(uint256 const&, std::shared_ptr<NodeObject>*) override
     {
         return notFound;
     }
 
     std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
-    fetchBatch(std::vector<uint256 const*> const& hashes) override
+    fetchBatch(std::vector<uint256> const& hashes) override
     {
         return {};
     }

src/libxrpl/nodestore/backend/RocksDBFactory.cpp

@@ -244,7 +244,7 @@ public:
     //--------------------------------------------------------------------------
 
     Status
-    fetch(void const* key, std::shared_ptr<NodeObject>* pObject) override
+    fetch(uint256 const& hash, std::shared_ptr<NodeObject>* pObject) override
     {
         XRPL_ASSERT(m_db, "xrpl::NodeStore::RocksDBBackend::fetch : non-null database");
         pObject->reset();
@@ -252,7 +252,7 @@ public:
         Status status(ok);
 
         rocksdb::ReadOptions const options;
-        rocksdb::Slice const slice(static_cast<char const*>(key), m_keyBytes);
+        rocksdb::Slice const slice(std::bit_cast<char const*>(hash.data()), m_keyBytes);
 
         std::string string;
 
@@ -260,7 +260,7 @@ public:
 
         if (getStatus.ok())
         {
-            DecodedBlob decoded(key, string.data(), string.size());
+            DecodedBlob decoded(hash.data(), string.data(), string.size());
 
             if (decoded.wasOk())
             {
@@ -295,14 +295,14 @@ public:
     }
 
     std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
-    fetchBatch(std::vector<uint256 const*> const& hashes) override
+    fetchBatch(std::vector<uint256> const& hashes) override
     {
         std::vector<std::shared_ptr<NodeObject>> results;
         results.reserve(hashes.size());
         for (auto const& h : hashes)
         {
             std::shared_ptr<NodeObject> nObj;
-            Status status = fetch(h->begin(), &nObj);
+            Status status = fetch(h, &nObj);
             if (status != ok)
                 results.push_back({});
             else
@@ -332,9 +332,8 @@ public:
             EncodedBlob encoded(e);
 
             wb.Put(
-                rocksdb::Slice(reinterpret_cast<char const*>(encoded.getKey()), m_keyBytes),
+                rocksdb::Slice(std::bit_cast<char const*>(encoded.getKey()), m_keyBytes),
-                rocksdb::Slice(
+                rocksdb::Slice(std::bit_cast<char const*>(encoded.getData()), encoded.getSize()));
-                    reinterpret_cast<char const*>(encoded.getData()), encoded.getSize()));
         }
 
         rocksdb::WriteOptions const options;

src/test/nodestore/TestBase.h

@@ -138,7 +138,7 @@ public:
         {
             std::shared_ptr<NodeObject> object;
 
-            Status const status = backend.fetch(batch[i]->getHash().cbegin(), &object);
+            Status const status = backend.fetch(batch[i]->getHash(), &object);
 
             BEAST_EXPECT(status == ok);
 
@@ -158,7 +158,7 @@ public:
         {
             std::shared_ptr<NodeObject> object;
 
-            Status const status = backend.fetch(batch[i]->getHash().cbegin(), &object);
+            Status const status = backend.fetch(batch[i]->getHash(), &object);
 
             BEAST_EXPECT(status == notFound);
         }

src/test/nodestore/Timing_test.cpp

@@ -314,7 +314,7 @@ public:
                     std::shared_ptr<NodeObject> obj;
                     std::shared_ptr<NodeObject> result;
                     obj = seq1_.obj(dist_(gen_));
-                    backend_.fetch(obj->getHash().data(), &result);
+                    backend_.fetch(obj->getHash(), &result);
                     suite_.expect(result && isSame(result, obj));
                 }
                 catch (std::exception const& e)
@@ -377,9 +377,9 @@ public:
             {
                 try
                 {
-                    auto const key = seq2_.key(i);
+                    auto const hash = seq2_.key(i);
                     std::shared_ptr<NodeObject> result;
-                    backend_.fetch(key.data(), &result);
+                    backend_.fetch(hash, &result);
                     suite_.expect(!result);
                 }
                 catch (std::exception const& e)
@@ -449,9 +449,9 @@ public:
                 {
                     if (rand_(gen_) < missingNodePercent)
                     {
-                        auto const key = seq2_.key(dist_(gen_));
+                        auto const hash = seq2_.key(dist_(gen_));
                         std::shared_ptr<NodeObject> result;
-                        backend_.fetch(key.data(), &result);
+                        backend_.fetch(hash, &result);
                         suite_.expect(!result);
                     }
                     else
@@ -459,7 +459,7 @@ public:
                         std::shared_ptr<NodeObject> obj;
                         std::shared_ptr<NodeObject> result;
                         obj = seq1_.obj(dist_(gen_));
-                        backend_.fetch(obj->getHash().data(), &result);
+                        backend_.fetch(obj->getHash(), &result);
                         suite_.expect(result && isSame(result, obj));
                     }
                 }
@@ -540,8 +540,7 @@ public:
                         std::shared_ptr<NodeObject> result;
                         auto const j = older_(gen_);
                         obj = seq1_.obj(j);
-                        std::shared_ptr<NodeObject> result1;
+                        backend_.fetch(obj->getHash(), &result);
-                        backend_.fetch(obj->getHash().data(), &result);
                         suite_.expect(result != nullptr);
                         suite_.expect(isSame(result, obj));
                     }
@@ -559,7 +558,7 @@ public:
                                 std::shared_ptr<NodeObject> result;
                                 auto const j = recent_(gen_);
                                 obj = seq1_.obj(j);
-                                backend_.fetch(obj->getHash().data(), &result);
+                                backend_.fetch(obj->getHash(), &result);
                                 suite_.expect(!result || isSame(result, obj));
                                 break;
                             }

src/tests/libxrpl/basics/MallocTrim.cpp

@@ -0,0 +1,209 @@
+#include <xrpl/basics/MallocTrim.h>
+
+#include <boost/predef.h>
+
+#include <gtest/gtest.h>
+
+using namespace xrpl;
+
+// cSpell:ignore statm
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+namespace xrpl::detail {
+long
+parseStatmRSSkB(std::string const& statm);
+}  // namespace xrpl::detail
+#endif
+
+TEST(MallocTrimReport, structure)
+{
+    // Test default construction
+    MallocTrimReport report;
+    EXPECT_EQ(report.supported, false);
+    EXPECT_EQ(report.trimResult, -1);
+    EXPECT_EQ(report.rssBeforeKB, -1);
+    EXPECT_EQ(report.rssAfterKB, -1);
+    EXPECT_EQ(report.durationUs, std::chrono::microseconds{-1});
+    EXPECT_EQ(report.minfltDelta, -1);
+    EXPECT_EQ(report.majfltDelta, -1);
+    EXPECT_EQ(report.deltaKB(), 0);
+
+    // Test deltaKB calculation - memory freed
+    report.rssBeforeKB = 1000;
+    report.rssAfterKB = 800;
+    EXPECT_EQ(report.deltaKB(), -200);
+
+    // Test deltaKB calculation - memory increased
+    report.rssBeforeKB = 500;
+    report.rssAfterKB = 600;
+    EXPECT_EQ(report.deltaKB(), 100);
+
+    // Test deltaKB calculation - no change
+    report.rssBeforeKB = 1234;
+    report.rssAfterKB = 1234;
+    EXPECT_EQ(report.deltaKB(), 0);
+}
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+TEST(parseStatmRSSkB, standard_format)
+{
+    using xrpl::detail::parseStatmRSSkB;
+
+    // Test standard format: size resident shared text lib data dt
+    // Assuming 4KB page size: resident=1000 pages = 4000 KB
+    {
+        std::string statm = "25365 1000 2377 0 0 5623 0";
+        long result = parseStatmRSSkB(statm);
+        // Note: actual result depends on system page size
+        // On most systems it's 4KB, so 1000 pages = 4000 KB
+        EXPECT_GT(result, 0);
+    }
+
+    // Test with newline
+    {
+        std::string statm = "12345 2000 1234 0 0 3456 0\n";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_GT(result, 0);
+    }
+
+    // Test with tabs
+    {
+        std::string statm = "12345\t2000\t1234\t0\t0\t3456\t0";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_GT(result, 0);
+    }
+
+    // Test zero resident pages
+    {
+        std::string statm = "25365 0 2377 0 0 5623 0";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_EQ(result, 0);
+    }
+
+    // Test with extra whitespace
+    {
+        std::string statm = "  25365   1000   2377  ";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_GT(result, 0);
+    }
+
+    // Test empty string
+    {
+        std::string statm = "";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_EQ(result, -1);
+    }
+
+    // Test malformed data (only one field)
+    {
+        std::string statm = "25365";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_EQ(result, -1);
+    }
+
+    // Test malformed data (non-numeric)
+    {
+        std::string statm = "abc def ghi";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_EQ(result, -1);
+    }
+
+    // Test malformed data (second field non-numeric)
+    {
+        std::string statm = "25365 abc 2377";
+        long result = parseStatmRSSkB(statm);
+        EXPECT_EQ(result, -1);
+    }
+}
+#endif
+
+TEST(mallocTrim, without_debug_logging)
+{
+    beast::Journal journal{beast::Journal::getNullSink()};
+
+    MallocTrimReport report = mallocTrim("without_debug", journal);
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+    EXPECT_EQ(report.supported, true);
+    EXPECT_GE(report.trimResult, 0);
+    EXPECT_EQ(report.durationUs, std::chrono::microseconds{-1});
+    EXPECT_EQ(report.minfltDelta, -1);
+    EXPECT_EQ(report.majfltDelta, -1);
+#else
+    EXPECT_EQ(report.supported, false);
+    EXPECT_EQ(report.trimResult, -1);
+    EXPECT_EQ(report.rssBeforeKB, -1);
+    EXPECT_EQ(report.rssAfterKB, -1);
+    EXPECT_EQ(report.durationUs, std::chrono::microseconds{-1});
+    EXPECT_EQ(report.minfltDelta, -1);
+    EXPECT_EQ(report.majfltDelta, -1);
+#endif
+}
+
+TEST(mallocTrim, empty_tag)
+{
+    beast::Journal journal{beast::Journal::getNullSink()};
+    MallocTrimReport report = mallocTrim("", journal);
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+    EXPECT_EQ(report.supported, true);
+    EXPECT_GE(report.trimResult, 0);
+#else
+    EXPECT_EQ(report.supported, false);
+#endif
+}
+
+TEST(mallocTrim, with_debug_logging)
+{
+    struct DebugSink : public beast::Journal::Sink
+    {
+        DebugSink() : Sink(beast::severities::kDebug, false)
+        {
+        }
+        void
+        write(beast::severities::Severity, std::string const&) override
+        {
+        }
+        void
+        writeAlways(beast::severities::Severity, std::string const&) override
+        {
+        }
+    };
+
+    DebugSink sink;
+    beast::Journal journal{sink};
+
+    MallocTrimReport report = mallocTrim("debug_test", journal);
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+    EXPECT_EQ(report.supported, true);
+    EXPECT_GE(report.trimResult, 0);
+    EXPECT_GE(report.durationUs.count(), 0);
+    EXPECT_GE(report.minfltDelta, 0);
+    EXPECT_GE(report.majfltDelta, 0);
+#else
+    EXPECT_EQ(report.supported, false);
+    EXPECT_EQ(report.trimResult, -1);
+    EXPECT_EQ(report.durationUs, std::chrono::microseconds{-1});
+    EXPECT_EQ(report.minfltDelta, -1);
+    EXPECT_EQ(report.majfltDelta, -1);
+#endif
+}
+
+TEST(mallocTrim, repeated_calls)
+{
+    beast::Journal journal{beast::Journal::getNullSink()};
+
+    // Call malloc_trim multiple times to ensure it's safe
+    for (int i = 0; i < 5; ++i)
+    {
+        MallocTrimReport report = mallocTrim("iteration_" + std::to_string(i), journal);
+
+#if defined(__GLIBC__) && BOOST_OS_LINUX
+        EXPECT_EQ(report.supported, true);
+        EXPECT_GE(report.trimResult, 0);
+#else
+        EXPECT_EQ(report.supported, false);
+#endif
+    }
+}

src/xrpld/app/main/Application.cpp

@@ -31,6 +31,7 @@
 #include <xrpld/shamap/NodeFamily.h>
 
 #include <xrpl/basics/ByteUtilities.h>
+#include <xrpl/basics/MallocTrim.h>
 #include <xrpl/basics/ResolverAsio.h>
 #include <xrpl/basics/random.h>
 #include <xrpl/beast/asio/io_latency_probe.h>
@@ -1053,6 +1054,8 @@ public:
                                     << "; size after: " << cachedSLEs_.size();
         }
 
+        mallocTrim("doSweep", m_journal);
+
         // Set timer to do another sweep later.
         setSweepTimer();
     }