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

[Peter Collingbourne via libc-commits]

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

sysconf(_SC_PAGESIZE) is implemented now.


>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] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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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;