--- "Om.Turyx" <om.turyx@xxxxxxxxx> wrote: > Vincenzo Mallozzi wrote: > > Hi, > > from the kernel point of view, how can I > > understand if > > a memory page is locked? > > I'll explain better my question by means of an > > example. > Even with the example I could not really get what > you are asking. But > let me try.... > > I've two or more threads that, obviously, share > > some > > memory regions (so some memory pages). It can > > happens > > that one of these threads locks a memory page. > I assume you mean kernel threads. Or did you mean > two threads of execution? I mean user threads. Threads created by means of library such as "pthread_create" for C or "new Thread" for Java and so on. > > there a way to view that this page is locked by > > looking at the struct page fields of this memory > page? For locked I refer, for example, to a variable for which one of these threads calls a lock method (C) or a syncronize method (Java). Is already valid your dissertation? > If the page is locked in memory for some Disk I/O, > you can check the > status by testing using page->flags for PG_locked. > from page-flags.h, > /*... > * During disk I/O, PG_locked is used. This bit is > set before I/O and > * reset when I/O completes. page_waitqueue(page) is > a wait queue of all > tasks > * waiting for the I/O on this page to complete. > */ > > Is there a way to understand if another thread is > > trying to access to this locked page? > > If you intend to use one page as a shared resource, > you will have to > implement your own locking mechanism for serializing > the access I think I need to know if a page is locked by viewing at the page parameters. Further, I need to understand if some threads are in a deadlock state waiting for a lock to be released by one of they. Have you an idea? Have you heard about an already existing method or tool? > > HTH, > Om I hope I've now well explained the problem. Very very thanks. Vincenzo. Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
