-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Mon, 08 Sep 2003 09:26:59 -0700 Kirk True <ktrue@movaris.com> wrote: > 1. Regarding non-contiguous memory allocation, what is the need to > have *virtually* contiguous but not *physically* contiguous pages? It's usually better to map memory areas in contiguous page frames. In fact, this leads to a better use of the system cache. Moreover, if you access contiguous page frames, it's clear you'll experience better memory access times. I'm not talking about DMA who still requires it but I think it should be yet enough. There are few situations in which you really don't need it and can request the kernel for non-contiguous page frames f.e. when requests for memory areas are infrequent (just as example take a look at how Linux allocates space for a module). In these situations, vmalloc() is used. If you are asking yourself "why to do it?" the reason is really simple. In fact, in this way you can avoid memory external fragmentation. Hope this helps. - -- Angelo Dell'Aera 'buffer' Antifork Research, Inc. http://buffer.antifork.org PGP information in e-mail header -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/YFNSpONIzxnBXKIRAvm8AKC7RNUYE3P36sZaHfnHwmXLXm9vQgCgwiSc sGTZhs7Z9NkrYLevcmhCzow= =77U1 -----END PGP SIGNATURE----- -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
