[libc-commits] [libc] libc: Introduce calls to sysconf to get page size. (PR #163462)

[Peter Collingbourne via libc-commits]

https://github.com/pcc updated https://github.com/llvm/llvm-project/pull/163462

>From 1ed982952c3a1b615736e2dcccf7b8541b1d6949 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <pcc at google.com>
Date: Tue, 14 Oct 2025 14:55:56 -0700
Subject: [PATCH 1/2] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
 =?UTF-8?q?itial=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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Created using spr 1.3.6-beta.1
---
 libc/test/src/sys/mman/linux/mincore_test.cpp          | 5 +++--
 libc/test/src/sys/mman/linux/mlock_test.cpp            | 4 ++--
 libc/test/src/sys/mman/linux/msync_test.cpp            | 5 +++--
 libc/test/src/sys/mman/linux/remap_file_pages_test.cpp | 4 ++--
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/libc/test/src/sys/mman/linux/mincore_test.cpp b/libc/test/src/sys/mman/linux/mincore_test.cpp
index fb86252992def..7d470fc4b08b1 100644
--- a/libc/test/src/sys/mman/linux/mincore_test.cpp
+++ b/libc/test/src/sys/mman/linux/mincore_test.cpp
@@ -16,12 +16,13 @@
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
+#include <unistd.h>
+
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
 using LlvmLibcMincoreTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
 
 TEST_F(LlvmLibcMincoreTest, UnMappedMemory) {
   unsigned char vec;
diff --git a/libc/test/src/sys/mman/linux/mlock_test.cpp b/libc/test/src/sys/mman/linux/mlock_test.cpp
index f4a072ec18a31..834c513fdda0b 100644
--- a/libc/test/src/sys/mman/linux/mlock_test.cpp
+++ b/libc/test/src/sys/mman/linux/mlock_test.cpp
@@ -27,9 +27,9 @@
 #include "test/UnitTest/Test.h"
 
 #include <sys/syscall.h>
+#include <unistd.h>
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 using LlvmLibcMlockTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
diff --git a/libc/test/src/sys/mman/linux/msync_test.cpp b/libc/test/src/sys/mman/linux/msync_test.cpp
index 764a67d02e3b1..e99328992800b 100644
--- a/libc/test/src/sys/mman/linux/msync_test.cpp
+++ b/libc/test/src/sys/mman/linux/msync_test.cpp
@@ -15,8 +15,9 @@
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+#include <unistd.h>
+
+const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 using LlvmLibcMsyncTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
diff --git a/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp b/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
index 094bcb2c71427..f10c8d4211631 100644
--- a/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
+++ b/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
@@ -17,9 +17,9 @@
 
 #include <sys/mman.h>
 #include <sys/stat.h> // For S_IRWXU
+#include <unistd.h>
 
-// TODO: Replace with sysconf call once the function is properly implemented.
-constexpr size_t PAGE_SIZE = 4096;
+const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
 
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;

>From 4e70bf8b08187edc4af098afab194687596998d3 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <pcc at google.com>
Date: Tue, 14 Oct 2025 17:04:02 -0700
Subject: [PATCH 2/2] Address review comments

Created using spr 1.3.6-beta.1
---
 libc/test/src/sys/mman/linux/CMakeLists.txt            | 4 ++++
 libc/test/src/sys/mman/linux/mincore_test.cpp          | 5 ++---
 libc/test/src/sys/mman/linux/mlock_test.cpp            | 4 ++--
 libc/test/src/sys/mman/linux/msync_test.cpp            | 5 ++---
 libc/test/src/sys/mman/linux/remap_file_pages_test.cpp | 4 ++--
 5 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/libc/test/src/sys/mman/linux/CMakeLists.txt b/libc/test/src/sys/mman/linux/CMakeLists.txt
index a362c1cf61cbc..32fee920321c0 100644
--- a/libc/test/src/sys/mman/linux/CMakeLists.txt
+++ b/libc/test/src/sys/mman/linux/CMakeLists.txt
@@ -99,6 +99,7 @@ add_libc_unittest(
     libc.src.sys.mman.mincore
     libc.src.sys.mman.mlock
     libc.src.sys.mman.munlock
+    libc.src.unistd.sysconf
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
 )
@@ -123,6 +124,7 @@ add_libc_unittest(
     libc.src.sys.mman.mlockall
     libc.src.sys.mman.munlockall
     libc.src.sys.resource.getrlimit
+    libc.src.unistd.sysconf
     libc.src.__support.OSUtil.osutil
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
@@ -144,6 +146,7 @@ add_libc_unittest(
     libc.src.sys.mman.mincore
     libc.src.sys.mman.mlock
     libc.src.sys.mman.munlock
+    libc.src.unistd.sysconf
     libc.test.UnitTest.ErrnoCheckingTest
     libc.test.UnitTest.ErrnoSetterMatcher
 )
@@ -165,6 +168,7 @@ add_libc_unittest(
     libc.src.sys.mman.munmap
     libc.src.fcntl.open
     libc.src.unistd.close
+    libc.src.unistd.sysconf
 )
 
 add_libc_unittest(
diff --git a/libc/test/src/sys/mman/linux/mincore_test.cpp b/libc/test/src/sys/mman/linux/mincore_test.cpp
index 7d470fc4b08b1..1806bb1d671a2 100644
--- a/libc/test/src/sys/mman/linux/mincore_test.cpp
+++ b/libc/test/src/sys/mman/linux/mincore_test.cpp
@@ -12,17 +12,16 @@
 #include "src/sys/mman/mmap.h"
 #include "src/sys/mman/munlock.h"
 #include "src/sys/mman/munmap.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
-#include <unistd.h>
-
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
 using LlvmLibcMincoreTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
 
-const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 TEST_F(LlvmLibcMincoreTest, UnMappedMemory) {
   unsigned char vec;
diff --git a/libc/test/src/sys/mman/linux/mlock_test.cpp b/libc/test/src/sys/mman/linux/mlock_test.cpp
index 834c513fdda0b..0056ccf7f0b3d 100644
--- a/libc/test/src/sys/mman/linux/mlock_test.cpp
+++ b/libc/test/src/sys/mman/linux/mlock_test.cpp
@@ -22,14 +22,14 @@
 #include "src/sys/mman/munlockall.h"
 #include "src/sys/mman/munmap.h"
 #include "src/sys/resource/getrlimit.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
 #include <sys/syscall.h>
-#include <unistd.h>
 
-const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 using LlvmLibcMlockTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
diff --git a/libc/test/src/sys/mman/linux/msync_test.cpp b/libc/test/src/sys/mman/linux/msync_test.cpp
index e99328992800b..bf9640d39ebd6 100644
--- a/libc/test/src/sys/mman/linux/msync_test.cpp
+++ b/libc/test/src/sys/mman/linux/msync_test.cpp
@@ -11,13 +11,12 @@
 #include "src/sys/mman/msync.h"
 #include "src/sys/mman/munlock.h"
 #include "src/sys/mman/munmap.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
-#include <unistd.h>
-
-const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 using LlvmLibcMsyncTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
diff --git a/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp b/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
index f10c8d4211631..08ffffe35ab2d 100644
--- a/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
+++ b/libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
@@ -11,15 +11,15 @@
 #include "src/sys/mman/munmap.h"
 #include "src/sys/mman/remap_file_pages.h"
 #include "src/unistd/close.h"
+#include "src/unistd/sysconf.h"
 #include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/ErrnoSetterMatcher.h"
 #include "test/UnitTest/Test.h"
 
 #include <sys/mman.h>
 #include <sys/stat.h> // For S_IRWXU
-#include <unistd.h>
 
-const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
+const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);
 
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
 using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;