SERVER-16571 Use Actual Memory Constraint vs. Total System Memory When They Differ

(cherry picked from commit d535bce1bb7df20158fad965142d6b802ea95c60)

10 files changed, 43 insertions, 2 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index e98200213d0..76c666b0f0d 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -1749,6 +1749,9 @@ env.Library(
         '$BUILD_DIR/mongo/base',
         '$BUILD_DIR/mongo/util/net/network',
     ],
+    LIBDEPS_PRIVATE=[
+        '$BUILD_DIR/mongo/util/processinfo',
+    ],
 )
 
 env.Library(
diff --git a/src/mongo/db/commands/generic_servers.cpp b/src/mongo/db/commands/generic_servers.cpp
index 93ad3389461..a4e65bdf38d 100644
--- a/src/mongo/db/commands/generic_servers.cpp
+++ b/src/mongo/db/commands/generic_servers.cpp
@@ -123,7 +123,8 @@ public:
         bSys.appendDate("currentTime", jsTime());
         bSys.append("hostname", prettyHostName());
         bSys.append("cpuAddrSize", p.getAddrSize());
-        bSys.append("memSizeMB", static_cast<unsigned>(p.getMemSizeMB()));
+        bSys.append("memSizeMB", static_cast<unsigned>(p.getSystemMemSizeMB()));
+        bSys.append("memLimitMB", static_cast<unsigned>(p.getMemSizeMB()));
         bSys.append("numCores", p.getNumCores());
         bSys.append("cpuArch", p.getArch());
         bSys.append("numaEnabled", p.hasNumaEnabled());
diff --git a/src/mongo/db/log_process_details.cpp b/src/mongo/db/log_process_details.cpp
index 22eaca0cd20..6460ab12324 100644
--- a/src/mongo/db/log_process_details.cpp
+++ b/src/mongo/db/log_process_details.cpp
@@ -56,6 +56,11 @@ void logProcessDetails() {
     log() << mongodVersion(vii);
     vii.logBuildInfo();
 
+    if (ProcessInfo::getMemSizeMB() < ProcessInfo::getSystemMemSizeMB()) {
+        log() << ProcessInfo::getMemSizeMB() << " MB of memory available to the process out of "
+              << ProcessInfo::getSystemMemSizeMB() << " MB total system memory";
+    }
+
     printCommandLineOpts();
 }
 
diff --git a/src/mongo/util/processinfo.h b/src/mongo/util/processinfo.h
index 3af9ebb0f5f..408e633bd9b 100644
--- a/src/mongo/util/processinfo.h
+++ b/src/mongo/util/processinfo.h
@@ -87,9 +87,16 @@ public:
     }
 
     /**
-     * Get the total amount of system memory in MB
+     * Get the size of total memory available to the process in MB
      */
     static unsigned long long getMemSizeMB() {
+        return sysInfo().memLimit / (1024 * 1024);
+    }
+
+    /**
+     * Get the total memory available on the machine in MB
+     */
+    static unsigned long long getSystemMemSizeMB() {
         return sysInfo().memSize / (1024 * 1024);
     }
 
@@ -199,6 +206,7 @@ private:
         std::string osVersion;
         unsigned addrSize;
         unsigned long long memSize;
+        unsigned long long memLimit;
         unsigned numCores;
         unsigned long long pageSize;
         std::string cpuArch;
@@ -220,6 +228,7 @@ private:
         SystemInfo()
             : addrSize(0),
               memSize(0),
+              memLimit(0),
               numCores(0),
               pageSize(0),
               hasNuma(false),
diff --git a/src/mongo/util/processinfo_freebsd.cpp b/src/mongo/util/processinfo_freebsd.cpp
index 075fea72ffd..7657a85c590 100644
--- a/src/mongo/util/processinfo_freebsd.cpp
+++ b/src/mongo/util/processinfo_freebsd.cpp
@@ -146,6 +146,7 @@ void ProcessInfo::SystemInfo::collectSystemInfo() {
     uintptr_t defaultNum = 1;
     status = getSysctlByNameWithDefault("hw.physmem", defaultNum, &numBuffer);
     memSize = numBuffer;
+    memLimit = memSize;
     if (status != 0)
         log() << "Unable to collect Physical Memory. (errno: " << status
               << " msg: " << strerror(status) << ")";
diff --git a/src/mongo/util/processinfo_linux.cpp b/src/mongo/util/processinfo_linux.cpp
index cb91e199d74..67cd7fea0ca 100644
--- a/src/mongo/util/processinfo_linux.cpp
+++ b/src/mongo/util/processinfo_linux.cpp
@@ -415,6 +415,23 @@ public:
         }
         return 0;
     }
+
+    /**
+    * Get memory limit for the process.
+    * If memory is being limited by the applied control group and it's less
+    * than the OS system memory (default cgroup limit is ulonglong max) let's
+    * return the actual memory we'll have available to the process.
+    */
+    static unsigned long long getMemorySizeLimit() {
+        unsigned long long systemMemBytes = getSystemMemorySize();
+        unsigned long long cgroupMemBytes = 0;
+        std::string cgmemlimit = readLineFromFile("/sys/fs/cgroup/memory/memory.limit_in_bytes");
+        if (!cgmemlimit.empty() &&
+            mongo::parseNumberFromString(cgmemlimit, &cgroupMemBytes).isOK()) {
+            return std::min(systemMemBytes, cgroupMemBytes);
+        }
+        return systemMemBytes;
+    }
 };
 
 
@@ -490,6 +507,7 @@ void ProcessInfo::SystemInfo::collectSystemInfo() {
     osName = distroName;
     osVersion = distroVersion;
     memSize = LinuxSysHelper::getSystemMemorySize();
+    memLimit = LinuxSysHelper::getMemorySizeLimit();
     addrSize = sizeof(void*) * CHAR_BIT;
     numCores = cpuCount;
     pageSize = static_cast<unsigned long long>(sysconf(_SC_PAGESIZE));
diff --git a/src/mongo/util/processinfo_openbsd.cpp b/src/mongo/util/processinfo_openbsd.cpp
index 7d3fa570992..4fc381405e9 100644
--- a/src/mongo/util/processinfo_openbsd.cpp
+++ b/src/mongo/util/processinfo_openbsd.cpp
@@ -163,6 +163,7 @@ void ProcessInfo::SystemInfo::collectSystemInfo() {
     mib[1] = HW_PHYSMEM;
     status = getSysctlByIDWithDefault(mib, 2, defaultNum, &numBuffer);
     memSize = numBuffer;
+    memLimit = memSize;
     if (status != 0)
         log() << "Unable to collect Physical Memory. (errno: " << status
               << " msg: " << strerror(status) << ")";
diff --git a/src/mongo/util/processinfo_osx.cpp b/src/mongo/util/processinfo_osx.cpp
index daac6a766cf..4ab77968a8b 100644
--- a/src/mongo/util/processinfo_osx.cpp
+++ b/src/mongo/util/processinfo_osx.cpp
@@ -189,6 +189,7 @@ void ProcessInfo::SystemInfo::collectSystemInfo() {
     osVersion = getSysctlByName<string>("kern.osrelease");
     addrSize = (getSysctlByName<NumberVal>("hw.cpu64bit_capable") ? 64 : 32);
     memSize = getSysctlByName<NumberVal>("hw.memsize");
+    memLimit = memSize;
     numCores = getSysctlByName<NumberVal>("hw.ncpu");  // includes hyperthreading cores
     pageSize = static_cast<unsigned long long>(sysconf(_SC_PAGESIZE));
     cpuArch = getSysctlByName<string>("hw.machine");
diff --git a/src/mongo/util/processinfo_solaris.cpp b/src/mongo/util/processinfo_solaris.cpp
index b115a41a008..9b8cc0c8caf 100644
--- a/src/mongo/util/processinfo_solaris.cpp
+++ b/src/mongo/util/processinfo_solaris.cpp
@@ -162,6 +162,7 @@ void ProcessInfo::SystemInfo::collectSystemInfo() {
     osVersion = unameData.version;
     pageSize = static_cast<unsigned long long>(sysconf(_SC_PAGESIZE));
     memSize = pageSize * static_cast<unsigned long long>(sysconf(_SC_PHYS_PAGES));
+    memLimit = memSize;
     numCores = static_cast<unsigned>(sysconf(_SC_NPROCESSORS_CONF));
     cpuArch = unameData.machine;
     hasNuma = checkNumaEnabled();
diff --git a/src/mongo/util/processinfo_windows.cpp b/src/mongo/util/processinfo_windows.cpp
index 8685d466127..02dd7d4fa86 100644
--- a/src/mongo/util/processinfo_windows.cpp
+++ b/src/mongo/util/processinfo_windows.cpp
@@ -289,6 +289,7 @@ void ProcessInfo::SystemInfo::collectSystemInfo() {
     mse.dwLength = sizeof(mse);
     if (GlobalMemoryStatusEx(&mse)) {
         memSize = mse.ullTotalPhys;
+        memLimit = memSize;
     }
 
     // get OS version info