]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: documentation: remove hopelessly out-of-date locking doc
authorDave Hansen <dave.hansen@intel.com>
Thu, 23 Jan 2014 23:52:47 +0000 (15:52 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 24 Jan 2014 00:36:50 +0000 (16:36 -0800)
commit57ea8171d2bc245e22e760d2e4292da8e5a15175
tree1be4c08906126c6490b369300f51e5283cd9b472
parent372c7209d6a05130b9d867f7ba350dec19e54030
mm: documentation: remove hopelessly out-of-date locking doc

Documentation/vm/locking is a blast from the past.  In the entire git
history, it has had precisely Three modifications.  Two of those look to
be pure renames, and the third was from 2005.

The doc contains such gems as:

> The page_table_lock is grabbed while holding the
> kernel_lock spinning monitor.

> Page stealers hold kernel_lock to protect against a bunch of
> races.

Or this which talks about mmap_sem:

> 4. The exception to this rule is expand_stack, which just
>    takes the read lock and the page_table_lock, this is ok
>    because it doesn't really modify fields anybody relies on.

expand_stack() doesn't take any locks any more directly, and the
mmap_sem acquisition was long ago moved up in to the page fault code
itself.

It could be argued that we need to rewrite this, but it is dangerous to
leave it as-is.  It will confuse more people than it helps.

Signed-off-by: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation/vm/locking [deleted file]