diff --git a/io.c b/io.c
index 7bf5543..65f8804 100644
--- a/io.c
+++ b/io.c
@@ -2098,6 +2098,19 @@ io_setstrbuf(VALUE *str,long len)
 #endif
 }
 
+#ifdef HAVE_POSIX_FADVISE
+struct io_advise_struct {
+    int fd;
+    off_t offset;
+    off_t len;
+    int advice;
+};
+
+#ifdef POSIX_FADV_SEQUENTIAL
+static VALUE io_advise_internal(void *arg);
+#endif /* POSIX_FADV_SEQUENTIAL */
+#endif /* HAVE_POSIX_FADVISE */
+
 static VALUE
 read_all(rb_io_t *fptr, long siz, VALUE str)
 {
@@ -2107,6 +2120,18 @@ read_all(rb_io_t *fptr, long siz, VALUE str)
     rb_encoding *enc;
     int cr;
 
+#ifdef HAVE_POSIX_FADVISE
+#ifdef POSIX_FADV_SEQUENTIAL
+    struct io_advise_struct ias;
+
+    ias.fd     = fptr->fd;
+    ias.advice = POSIX_FADV_SEQUENTIAL;
+    ias.offset = 0;
+    ias.len = 0;
+    io_advise_internal(&ias);
+#endif /* POSIX_FADV_SEQUENTIAL */
+#endif /* HAVE_POSIX_FADVISE */
+
     if (NEED_READCONV(fptr)) {
 	SET_BINARY_MODE(fptr);
 	io_setstrbuf(&str,0);
@@ -7894,13 +7919,6 @@ static VALUE sym_normal,   sym_sequential, sym_random,
              sym_willneed, sym_dontneed, sym_noreuse;
 
 #ifdef HAVE_POSIX_FADVISE
-struct io_advise_struct {
-    int fd;
-    off_t offset;
-    off_t len;
-    int advice;
-};
-
 static VALUE
 io_advise_internal(void *arg)
 {