Call posix_fadvise() each time we open a new file, not just on the first one.

docs/NEWS.md

@@ -9,6 +9,7 @@
  * fix: surround average rate ("`--average-rate`") with brackets rather than square brackets
  * fix: correct a memory leak in "`--watchfd PID`"
  * fix: make "`--direct-io`" work correctly with "`--output`" instead of assuming stdout
+ * fix: call `posix_fadvise()` on every input, not just the first one
  * fix: write UTC timestamps in debugging mode to avoid lockups in signal handlers
  * cleanup: removed TODO.md, since it's just an outdated copy of the issue tracker
  * cleanup: re-ordered structure members to reduce padding

src/pv/loop.c

@@ -258,6 +258,10 @@ int pv_main_loop(pvstate_t state)
 			if (input_fd >= 0) {
 				eof_in = false;
 				eof_out = false;
+#if HAVE_POSIX_FADVISE
+				/* Advise the OS that we will only be reading sequentially. */
+				(void) posix_fadvise(input_fd, 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
 			}
 		}