On Wed, Feb 15, 2017 at 12:29:04PM -0800, Andrew Morton wrote: > On Wed, 15 Feb 2017 19:14:54 +0300 Cyrill Gorcunov <[email protected]> wrote: > > > When we checkpoint a process we look into /proc/<pid>/fdinfo/<fd> of > > eventpoll > > file and parse target files list from there. In most situations this is fine > > because target file is present in the /proc/<pid>/fd/ list. But in case if > > file > > descriptor was dup'ed or transferred via unix socket and closed after, > > it might not be in the list and we can't figure out which file descriptor > > to pass into epoll_ctl call. > > > > To resolve this tie lets add EPOLL_CTL_ITF ("itf" stands for install > > target file) operation which simply takes target file descriptor number > > and installs it into a caller's file table, thus we can use kcmp() > > syscall and figure out which exactly file to be added into > > eventpoll on restore procedure. > > Can we please see the proposed manpage update. And Cc linux-api and > Michael Kerrisk.
Sure! Will do (I didn't write it immediately 'cause wanted to see if the idea of new operation won't be rejected immediately, that is why it is rfc). > > #define EPOLL_CTL_ADD 1 > > #define EPOLL_CTL_DEL 2 > > #define EPOLL_CTL_MOD 3 > > +#define EPOLL_CTL_ITF 4 > > Somewhere we should tell the poor reader what "itf" means. A comment > here would suit. I thought maybe some better name come to mind... Say EPOLL_CTL_INS, except INS usually associated with "insert"?
