Add explanatory comments to filesys tests.

[pintos-anon] / src / tests / filesys / extended / child-syn-rw.c

diff --git a/src/tests/filesys/extended/child-syn-rw.c b/src/tests/filesys/extended/child-syn-rw.c
index 6334bda0b1077d97707df098c44a9f30b87d277c..434a542e25a58cf4491aafb1b2bcc1c72ec10b5d 100644 (file)
--- a/src/tests/filesys/extended/child-syn-rw.c
+++ b/src/tests/filesys/extended/child-syn-rw.c
@@ -1,3 +1,12 @@
+/* Child process for syn-rw.
+   Reads from a file created by our parent process, which is
+   growing it.  We loop until we've read the whole file
+   successfully.  Many iterations through the loop will return 0
+   bytes, because the file has not grown in the meantime.  That
+   is, we are "busy waiting" for the file to grow.
+   (This test could be improved by adding a "yield" system call
+   and calling yield whenever we receive a 0-byte read.) */
+
 #include <random.h>
 #include <stdlib.h>
 #include <syscall.h>