On 30.11.2020 18:34, Peter Xu wrote:
On Sun, Nov 29, 2020 at 11:12:10PM +0300, Andrey Gruzdev wrote:
+void ram_write_tracking_stop(void)
+{
+#ifdef CONFIG_LINUX
+ RAMState *rs = ram_state;
+ RAMBlock *bs;
+ assert(rs->uffdio_fd >= 0);
Maybe too harsh - we can return if it's invalid.
Meanwhile, better rcu_read_lock(), as well?
Yep, RCU lock, I'll add. Why too harsh? Just a debug assertion.
I was afraid some special path could trigger ram_write_tracking_stop() being
called before ram_write_tracking_start(), then vm could crash. If we can
guarantee that not happening, then it's also ok with assert().
[...]
It can't really happen, but I agree that assert() is a bit excessive here.
+/**
+ * uffd_poll_events: poll UFFD file descriptor for read
+ *
+ * Returns true if events are available for read, false otherwise
+ *
+ * @uffd: UFFD file descriptor
+ * @tmo: timeout in milliseconds, 0 for non-blocking operation,
+ * negative value for infinite wait
+ */
+bool uffd_poll_events(int uffd, int tmo)
Shall we spell "tmo" out?
In the comment? I think it's ok.
I'd suggest to spell it out everywhere, especially in the codes. But feel free
to take your own preference. Thanks,
Thanks,
--
Andrey Gruzdev, Principal Engineer
Virtuozzo GmbH +7-903-247-6397
virtuzzo.com
