On 2014/10/17 16:33, Daniel P. Berrange wrote: > On Fri, Oct 17, 2014 at 04:27:17PM +0800, haifeng....@huawei.com wrote: >> From: linhaifeng <haifeng....@huawei.com> >> >> The VM start with share hugepage should close the hugefile fd >> when exit.Because the hugepage fd may be send to other process >> e.g vhost-user If qemu not close the fd the other process can >> not free the hugepage otherwise exit process,this is ugly,so >> qemu should close all shared fd when exit. >> >> Signed-off-by: linhaifeng <haifeng....@huawei.com> > > Err, all file descriptors are closed automatically when a process > exits. So manually calling close(fd) before exit can't have any > functional effect on a resource leak. > > If QEMU has sent the FD to another process, that process has a > completely separate copy of the FD. Closing the FD in QEMU will > not close the FD in the other process. You need the other process > to exit for the copy to be closed. >
Actually, when vhost-user close the FD manually, the hugepage leak too unless the vhost-user process exit. So, maybe the FD is not a separate copy IMHO, but simply add the ref-count of FD. When QEMU exit, because the ref is not zero, the operate system will not free the FD automatically, and when vhost-user close the FD, because of the same reason, OS will not free FD resource. BTW, I don't think this patch is good. When Qemu exit exceptionally, sush as 'by kill -9', this problem of memory leak still exist. Best Regards, -Gonglei
