feat(journal): add posix compatible way of getting the page size

platonic-io · Dec 21, 2021 · ac30608 · ac30608
1 parent cf2b2fd
commit ac30608
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/src/journal/src/Journal/Internal/ByteBuffer.hs b/src/journal/src/Journal/Internal/ByteBuffer.hs
@@ -108,7 +108,8 @@ allocateAligned capa align = do
 mmapped :: FilePath -> Int -> IO ByteBuffer
 mmapped fp capa = do
   fd <- openFd fp ReadWrite Nothing defaultFileFlags
-  bb <- allocateAligned capa 4096
+  pageSize <- sysconfPageSize
+  bb <- allocateAligned capa pageSize
   ptr <- mmap (Just (bbPtr bb)) (fromIntegral capa)
            (PROT (READ :| WRITE)) MAP_SHARED (Just fd) 0
   assert (ptr == bbPtr bb) (return ())

diff --git a/src/journal/src/Journal/Internal/Mmap.hs b/src/journal/src/Journal/Internal/Mmap.hs
@@ -25,6 +25,9 @@ foreign import ccall unsafe "sys/mman.h msync"
 foreign import ccall unsafe "stdlib.h posix_memalign"
   c_posix_memalign :: Ptr (Ptr a) -> CSize -> CSize -> IO CInt
 
+foreign import ccall unsafe "unistd.h sysconf"
+  c_sysconf :: CInt -> IO CLong
+
 ------------------------------------------------------------------------
 
 mmap :: Maybe (Ptr a) -> Int -> MemoryProtection -> MemoryVisibility -> Maybe Fd
@@ -116,6 +119,9 @@ posixMemalign align size = do
     (c_posix_memalign memPtr (fromIntegral align) (fromIntegral size))
   peek memPtr
 
+sysconfPageSize :: IO Int
+sysconfPageSize = fromIntegral <$> c_sysconf 30
+
 ------------------------------------------------------------------------
 
   {-