src: clean up large_pages code

PR-URL: #31196
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

src/large_pages/node_large_page.cc

@@ -78,9 +78,12 @@ struct text_region {
 
 static const size_t hps = 2L * 1024 * 1024;
 
+static void PrintWarning(const char* warn) {
+  fprintf(stderr, "Hugepages WARNING: %s\n", warn);
+}
+
 static void PrintSystemError(int error) {
-  fprintf(stderr, "Hugepages WARNING: %s\n", strerror(error));
-  return;
+  PrintWarning(strerror(error));
 }
 
 inline uintptr_t hugepage_align_up(uintptr_t addr) {
@@ -94,7 +97,7 @@ inline uintptr_t hugepage_align_down(uintptr_t addr) {
 // The format of the maps file is the following
 // address           perms offset  dev   inode       pathname
 // 00400000-00452000 r-xp 00000000 08:02 173521      /usr/bin/dbus-daemon
-// This is also handling the case where the first line is not the binary
+// This is also handling the case where the first line is not the binary.
 
 static struct text_region FindNodeTextRegion() {
 #if defined(__linux__)
@@ -110,7 +113,7 @@ static struct text_region FindNodeTextRegion() {
 
   ifs.open("/proc/self/maps");
   if (!ifs) {
-    fprintf(stderr, "Could not open /proc/self/maps\n");
+    PrintWarning("could not open /proc/self/maps");
     return nregion;
   }
 
@@ -178,7 +181,7 @@ static struct text_region FindNodeTextRegion() {
     return nregion;
   }
 
-  // for struct kinfo_vmentry
+  // Enough for struct kinfo_vmentry.
   numpg = numpg * 4 / 3;
   auto alg = std::vector<char>(numpg);
 
@@ -262,39 +265,29 @@ static bool IsTransparentHugePagesEnabled() {
 
   ifs.open("/sys/kernel/mm/transparent_hugepage/enabled");
   if (!ifs) {
-    fprintf(stderr, "Could not open file: " \
-                    "/sys/kernel/mm/transparent_hugepage/enabled\n");
+    PrintWarning("could not open /sys/kernel/mm/transparent_hugepage/enabled");
     return false;
   }
 
-  std::string always, madvise, never;
+  std::string always, madvise;
   if (ifs.is_open()) {
-    while (ifs >> always >> madvise >> never) {}
+    while (ifs >> always >> madvise) {}
   }
-
-  int ret_status = false;
-
-  if (always.compare("[always]") == 0)
-    ret_status = true;
-  else if (madvise.compare("[madvise]") == 0)
-    ret_status = true;
-  else if (never.compare("[never]") == 0)
-    ret_status = false;
-
   ifs.close();
-  return ret_status;
+
+  return always == "[always]" || madvise == "[madvise]";
 }
 #elif defined(__FreeBSD__)
 static bool IsSuperPagesEnabled() {
-  // It is enabled by default on amd64
+  // It is enabled by default on amd64.
   unsigned int super_pages = 0;
   size_t super_pages_length = sizeof(super_pages);
-  if (sysctlbyname("vm.pmap.pg_ps_enabled", &super_pages,
-      &super_pages_length, nullptr, 0) == -1 ||
-      super_pages < 1) {
-    return false;
-  }
-  return true;
+  return sysctlbyname("vm.pmap.pg_ps_enabled",
+                      &super_pages,
+                      &super_pages_length,
+                      nullptr,
+                      0) != -1 &&
+         super_pages >= 1;
 }
 #endif
 
@@ -326,7 +319,7 @@ MoveTextRegionToLargePages(const text_region& r) {
   size_t size = r.to - r.from;
   void* start = r.from;
 
-  // Allocate temporary region preparing for copy
+  // Allocate temporary region preparing for copy.
   nmem = mmap(nullptr, size,
               PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   if (nmem == MAP_FAILED) {
@@ -413,11 +406,11 @@ MoveTextRegionToLargePages(const text_region& r) {
   return ret;
 }
 
-// This is the primary API called from main
+// This is the primary API called from main.
 int MapStaticCodeToLargePages() {
   struct text_region r = FindNodeTextRegion();
   if (r.found_text_region == false) {
-    fprintf(stderr, "Hugepages WARNING: failed to find text region\n");
+    PrintWarning("failed to find text region");
     return -1;
   }