In article <qwwyb2p0zld.fsf_-_@p21491.wdf.sap-ag.de> you write:
>[...]
>[... madvise ...]
>The need for MADV_DONTNEED is a similar problem: no memory manager can
>know that I really don't need a part of memory any more. It will
>always try to save the memory in backing store.
>But especially transactional programs process some memory and when the
>transaction finishes there is no need to get this content again. It
>will be overwritten by the next transaction. So the program can
>advise the OS to simply discard the page instead of saving the page to
>the swapfile. This can increase the system performance a lot under low
>physical memory.
I think you misunderstand the semantics of MADV_DONTNEED. The latter
means only that there will be no accesses to the given region soon.
It does IMHO *not* mean that the contents of that region don't matter
any more!
Regards, Felix.