linux.git/include/linux/mm.h, branch v3.13-rc3

Revert "mm: create a separate slab for page->ptl allocation"

2013-11-20T22:41:47+00:00

This reverts commit ea1e7ed33708c7a760419ff9ded0a6cb90586a50.

Al points out that while the commit *does* actually create a separate
slab for the page->ptl allocation, that slab is never actually used, and
the code continues to use kmalloc/kfree.

Damien Wyart points out that the original patch did have the conversion
to use kmem_cache_alloc/free, so it got lost somewhere on its way to me.

Revert the half-arsed attempt that didn't do anything.  If we really do
want the special slab (remember: this is all relevant just for debug
builds, so it's not necessarily all that critical) we might as well redo
the patch fully.

Reported-by: Al Viro 
Acked-by: Andrew Morton 
Cc: Kirill A Shutemov 
Signed-off-by: Linus Torvalds

mm: create a separate slab for page->ptl allocation

2013-11-15T00:32:20+00:00

If DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC are enabled spinlock_t on x86_64
is 72 bytes.  For page->ptl they will be allocated from kmalloc-96 slab,
so we loose 24 on each.  An average system can easily allocate few tens
thousands of page->ptl and overhead is significant.

Let's create a separate slab for page->ptl allocation to solve this.

Signed-off-by: Kirill A. Shutemov 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: properly separate the bloated ptl from the regular case

2013-11-15T00:32:20+00:00

Use kernel/bounds.c to convert build-time spinlock_t size check into a
preprocessor symbol and apply that to properly separate the page::ptl
situation.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Kirill A. Shutemov 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: dynamically allocate page->ptl if it cannot be embedded to struct page

2013-11-15T00:32:20+00:00

If split page table lock is in use, we embed the lock into struct page
of table's page.  We have to disable split lock, if spinlock_t is too
big be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC
enabled.

This patch add support for dynamic allocation of split page table lock
if we can't embed it to struct page.

page->ptl is unsigned long now and we use it as spinlock_t if
sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to spinlock_t.

The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
pgtable_pmd_page_ctor() for PMD table.  All other helpers converted to
support dynamically allocated page->ptl.

Signed-off-by: Kirill A. Shutemov 
Reviewed-by: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: allow pgtable_page_ctor() to fail

2013-11-15T00:32:16+00:00

Change pgtable_page_ctor() return type from void to bool.  Returns true,
if initialization is successful and false otherwise.

Current implementation never fails, but it will change later.

Signed-off-by: Kirill A. Shutemov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: implement split page table lock for PMD level

2013-11-15T00:32:15+00:00

The basic idea is the same as with PTE level: the lock is embedded into
struct page of table's page.

We can't use mm->pmd_huge_pte to store pgtables for THP, since we don't
take mm->page_table_lock anymore.  Let's reuse page->lru of table's page
for that.

pgtable_pmd_page_ctor() returns true, if initialization is successful
and false otherwise.  Current implementation never fails, but assumption
that constructor can fail will help to port it to -rt where spinlock_t
is rather huge and cannot be embedded into struct page -- dynamic
allocation is required.

Signed-off-by: Naoya Horiguchi 
Signed-off-by: Kirill A. Shutemov 
Tested-by: Alex Thorlton 
Cc: Ingo Molnar 
Cc: "Eric W . Biederman" 
Cc: "Paul E . McKenney" 
Cc: Al Viro 
Cc: Andi Kleen 
Cc: Andrea Arcangeli 
Cc: Dave Hansen 
Cc: Dave Jones 
Cc: David Howells 
Cc: Frederic Weisbecker 
Cc: Johannes Weiner 
Cc: Kees Cook 
Cc: Mel Gorman 
Cc: Michael Kerrisk 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Robin Holt 
Cc: Sedat Dilek 
Cc: Srikar Dronamraju 
Cc: Thomas Gleixner 
Cc: Hugh Dickins 
Reviewed-by: Steven Rostedt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, thp: do not access mm->pmd_huge_pte directly

2013-11-15T00:32:14+00:00

Currently mm->pmd_huge_pte protected by page table lock.  It will not
work with split lock.  We have to have per-pmd pmd_huge_pte for proper
access serialization.

For now, let's just introduce wrapper to access mm->pmd_huge_pte.

Signed-off-by: Kirill A. Shutemov 
Tested-by: Alex Thorlton 
Cc: Alex Thorlton 
Cc: Ingo Molnar 
Cc: Naoya Horiguchi 
Cc: "Eric W . Biederman" 
Cc: "Paul E . McKenney" 
Cc: Al Viro 
Cc: Andi Kleen 
Cc: Andrea Arcangeli 
Cc: Dave Hansen 
Cc: Dave Jones 
Cc: David Howells 
Cc: Frederic Weisbecker 
Cc: Johannes Weiner 
Cc: Kees Cook 
Cc: Mel Gorman 
Cc: Michael Kerrisk 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Robin Holt 
Cc: Sedat Dilek 
Cc: Srikar Dronamraju 
Cc: Thomas Gleixner 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce api for split page table lock for PMD level

2013-11-15T00:32:14+00:00

Basic api, backed by mm->page_table_lock for now. Actual implementation
will be added later.

Signed-off-by: Naoya Horiguchi 
Signed-off-by: Kirill A. Shutemov 
Tested-by: Alex Thorlton 
Cc: Ingo Molnar 
Cc: "Eric W . Biederman" 
Cc: "Paul E . McKenney" 
Cc: Al Viro 
Cc: Andi Kleen 
Cc: Andrea Arcangeli 
Cc: Dave Hansen 
Cc: Dave Jones 
Cc: David Howells 
Cc: Frederic Weisbecker 
Cc: Johannes Weiner 
Cc: Kees Cook 
Cc: Mel Gorman 
Cc: Michael Kerrisk 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Robin Holt 
Cc: Sedat Dilek 
Cc: Srikar Dronamraju 
Cc: Thomas Gleixner 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: rename USE_SPLIT_PTLOCKS to USE_SPLIT_PTE_PTLOCKS

2013-11-15T00:32:14+00:00

We're going to introduce split page table lock for PMD level.  Let's
rename existing split ptlock for PTE level to avoid confusion.

Signed-off-by: Kirill A. Shutemov 
Tested-by: Alex Thorlton 
Cc: Ingo Molnar 
Cc: Naoya Horiguchi 
Cc: "Eric W . Biederman" 
Cc: "Paul E . McKenney" 
Cc: Al Viro 
Cc: Andi Kleen 
Cc: Andrea Arcangeli 
Cc: Dave Hansen 
Cc: Dave Jones 
Cc: David Howells 
Cc: Frederic Weisbecker 
Cc: Johannes Weiner 
Cc: Kees Cook 
Cc: Mel Gorman 
Cc: Michael Kerrisk 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Robin Holt 
Cc: Sedat Dilek 
Cc: Srikar Dronamraju 
Cc: Thomas Gleixner 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memblock.c: introduce bottom-up allocation mode

2013-11-13T03:09:08+00:00

The Linux kernel cannot migrate pages used by the kernel.  As a result,
kernel pages cannot be hot-removed.  So we cannot allocate hotpluggable
memory for the kernel.

ACPI SRAT (System Resource Affinity Table) contains the memory hotplug
info.  But before SRAT is parsed, memblock has already started to allocate
memory for the kernel.  So we need to prevent memblock from doing this.

In a memory hotplug system, any numa node the kernel resides in should be
unhotpluggable.  And for a modern server, each node could have at least
16GB memory.  So memory around the kernel image is highly likely
unhotpluggable.

So the basic idea is: Allocate memory from the end of the kernel image and
to the higher memory.  Since memory allocation before SRAT is parsed won't
be too much, it could highly likely be in the same node with kernel image.

The current memblock can only allocate memory top-down.  So this patch
introduces a new bottom-up allocation mode to allocate memory bottom-up.
And later when we use this allocation direction to allocate memory, we
will limit the start address above the kernel.

Signed-off-by: Tang Chen 
Signed-off-by: Zhang Yanfei 
Acked-by: Toshi Kani 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Tejun Heo 
Cc: Wanpeng Li 
Cc: Thomas Renninger 
Cc: Yinghai Lu 
Cc: Jiang Liu 
Cc: Wen Congyang 
Cc: Lai Jiangshan 
Cc: Yasuaki Ishimatsu 
Cc: Taku Izumi 
Cc: Mel Gorman 
Cc: Michal Nazarewicz 
Cc: Minchan Kim 
Cc: Rik van Riel 
Cc: Johannes Weiner 
Cc: Kamezawa Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds