Lines Matching +full:two +full:- +full:user
9 List: linux-kernel
12 Date: 1999-07-30 21:36:24
14 Cc'd to linux-kernel, because I don't write explanations all that often,
21 > discussed on the mailing lists---I just returned from vacation and
22 > wasn't able to follow linux-kernel for a while).
26 - we have "real address spaces" and "anonymous address spaces". The
28 user-level page tables at all, so when we do a context switch into an
33 doesn't need any user mappings - all kernel threads basically fall into
35 some amount of time they are not going to be interested in user space,
37 switching the VM state around. Currently only the old-style bdflush
40 - "tsk->mm" points to the "real address space". For an anonymous process,
41 tsk->mm will be NULL, for the logical reason that an anonymous process
44 - however, we obviously need to keep track of which address space we
45 "stole" for such an anonymous user. For that, we have "tsk->active_mm",
48 The rule is that for a process with a real address space (ie tsk->mm is
49 non-NULL) the active_mm obviously always has to be the same as the real
52 For a anonymous process, tsk->mm == NULL, and tsk->active_mm is the
57 To support all that, the "struct mm_struct" now has two counters: a
62 Usually there is at least one real user, but it could be that the real
63 user exited on another CPU while a lazy user was still active, so you do
65 lazy users. That is often a short-lived state, because once that thread
74 if (current->mm == &init_mm)
78 if (!current->mm)
80 instead (which makes more sense anyway - the test is basically one of "do
81 we have a user context", and is generally done by the page fault handler
84 Anyway, I put a pre-patch-2.3.13-1 on ftp.kernel.org just a moment ago,
87 ugliest context switch codes - unlike the other architectures where the MM
88 and register state is separate, the alpha PALcode joins the two, and you
91 (From http://marc.info/?l=linux-kernel&m=93337278602211&w=2)