linux.git/mm/migrate.c, branch v2.6.24

Typo fixes retrun -> return

2007-10-20T00:13:26+00:00

Typo fixes retrun -> return

Signed-off-by: Gabriel Craciunescu 
Signed-off-by: Adrian Bunk

Uninline find_task_by_xxx set of functions

2007-10-19T18:53:40+00:00

The find_task_by_something is a set of macros are used to find task by pid
depending on what kind of pid is proposed - global or virtual one.  All of
them are wrappers above the most generic one - find_task_by_pid_type_ns() -
and just substitute some args for it.

It turned out, that dereferencing the current->nsproxy->pid_ns construction
and pushing one more argument on the stack inline cause kernel text size to
grow.

This patch moves all this stuff out-of-line into kernel/pid.c.  Together
with the next patch it saves a bit less than 400 bytes from the .text
section.

Signed-off-by: Pavel Emelyanov 
Cc: Sukadev Bhattiprolu 
Cc: Oleg Nesterov 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Acked-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: changes to show virtual ids to user

2007-10-19T18:53:40+00:00

This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov 
Signed-off-by: Alexey Dobriyan 
Cc: Sukadev Bhattiprolu 
Cc: Oleg Nesterov 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

flush icache before set_pte() on ia64: flush icache at set_pte

2007-10-16T16:42:59+00:00

Current ia64 kernel flushes icache by lazy_mmu_prot_update() *after*
set_pte().  This is too late.  This patch removes lazy_mmu_prot_update and
add modfied set_pte() for flushing if necessary.

This patch flush icache of a page when
	new pte has exec bit.
	&& new pte has present bit
	&& new pte is user's page.
	&& (old *ptep is not present
            || new pte's pfn is not same to old *ptep's ptn)
	&& new pte's page has no Pg_arch_1 bit.
	   Pg_arch_1 is set when a page is cache consistent.

I think this condition checks are much easier to understand than considering
"Where sync_icache_dcache() should be inserted ?".

pte_user() for ia64 was removed by http://lkml.org/lkml/2007/6/12/67 as
clean-up. So, I added it again.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: "Luck, Tony" 
Cc: Christoph Lameter 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

flush cache before installing new page at migraton

2007-10-16T16:42:59+00:00

In migration, a new page should be cache flushed before set_pte() in some
archs which have virtually-tagged cache.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: "Luck, Tony" 
Cc: Christoph Lameter 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Memoryless nodes: Update memory policy and page migration

2007-10-16T16:42:58+00:00

Online nodes now may have no memory.  The checks and initialization must
therefore be changed to no longer use the online functions.

This will correctly initialize the interleave on bootup to only target nodes
with memory and will make sys_move_pages return an error when a page is to be
moved to a memoryless node.  Similarly we will get an error if MPOL_BIND and
MPOL_INTERLEAVE is used on a memoryless node.

These are somewhat new semantics.  So far one could specify memoryless nodes
and we would maybe do the right thing and just ignore the node (or we'd do
something strange like with MPOL_INTERLEAVE).  If we want to allow the
specification of memoryless nodes via memory policies then we need to keep
checking for online nodes.

Signed-off-by: Christoph Lameter 
Acked-by: Nishanth Aravamudan 
Tested-by: Lee Schermerhorn 
Acked-by: Bob Picco 
Cc: KAMEZAWA Hiroyuki 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/migrate.c __user annotation

2007-10-14T19:41:51+00:00

Signed-off-by: Al Viro 
Signed-off-by: Linus Torvalds

fix rcu_read_lock() in page migraton

2007-08-31T08:42:22+00:00

In migration fallback path, write_page() or lock_page() will be called.
This causes sleep with holding rcu_read_lock().
For avoding that, just do rcu_lock if the page is Anon.(this is enough.)

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory unplug: isolate_lru_page fix

2007-07-26T18:35:17+00:00

release_pages() in mm/swap.c changes page_count() to be 0 without removing
PageLRU flag...

This means isolate_lru_page() can see a page, PageLRU() &&
page_count(page)==0..  This is BUG.  (get_page() will be called against
count=0 page.)

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory unplug: migration by kernel

2007-07-26T18:35:17+00:00

In usual, migrate_pages(page,,) is called with holding mm->sem by system call.
(mm here is a mm_struct which maps the migration target page.)
This semaphore helps avoiding some race conditions.

But, if we want to migrate a page by some kernel codes, we have to avoid
some races. This patch adds check code for following race condition.

1. A page which page->mapping==NULL can be target of migration. Then, we have
   to check page->mapping before calling try_to_unmap().

2. anon_vma can be freed while page is unmapped, but page->mapping remains as
   it was. We drop page->mapcount to be 0. Then we cannot trust page->mapping.
   So, use rcu_read_lock() to prevent anon_vma pointed by page->mapping from
   being freed during migration.

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds