Developer documentation should be its own manual.  As a start, move all
developer-oriented files to a separate directory.

Also move non-text files to their own directories: docs/config/ for
QEMU -readconfig input, and docs/spin/ for formal models to be used
with the SPIN model checker.
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

s/presented/prevented/
Signed-off-by: NPranith Kumar <bobby.prani@gmail.com>
Message-Id: <20161018050418.4912-1-bobby.prani@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NCao jin <caoj.fnst@cn.fujitsu.com>
Message-Id: <1472696479-3619-1-git-send-email-caoj.fnst@cn.fujitsu.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The first argument of g_free_rcu() is a pointer to a structure.  But
foo_reclaim is used as a function name in the previous example along
with &foo as a pointer to the structure being reclaimed.  Make the
example consistent with the previous one.
Signed-off-by: NSergey Fedorov <serge.fdrv@gmail.com>
Message-Id: <1444837604-13712-1-git-send-email-serge.fdrv@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This simplifies calling g_free from an RCU callback.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Asynchronous callbacks provided by call_rcu are particularly important
for QEMU, because the BQL makes it hard to use synchronize_rcu.

In addition, the current RCU implementation is not particularly friendly
to multiple concurrent synchronize_rcu callers, making call_rcu even
more important.
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This includes a (mangled) copy of the liburcu code.  The main changes
are: 1) removing dependencies on many other header files in liburcu; 2)
removing for simplicity the tentative busy waiting in synchronize_rcu,
which has limited performance effects; 3) replacing futexes in
synchronize_rcu with QemuEvents for Win32 portability.  The API is
the same as liburcu, so it should be possible in the future to require
liburcu on POSIX systems for example and use our copy only on Windows.

Among the various versions available I chose urcu-mb, which is the
least invasive implementation even though it does not have the
fastest rcu_read_{lock,unlock} implementation.  The urcu flavor can
be changed later, after benchmarking.
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>