Why is memcg's swap accounting so broken? Insane counts, wrong
ownership, unfreeable structures, which later get freed and then
accessed after free.
Turns out to be a tiny a little 3.3-rc1 regression in 9fb4b7cc07
"page_cgroup: add helper function to get swap_cgroup": the helper
function (actually named lookup_swap_cgroup()) returns an address using
void* arithmetic, but the structure in question is a short.
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Bob Liu <lliubbo@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No need for two CONFIG_MEMORY_HOTPLUG blocks.
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are multiple places which need to get the swap_cgroup address, so
add a helper function:
static struct swap_cgroup *swap_cgroup_getsc(swp_entry_t ent,
struct swap_cgroup_ctrl **ctrl);
to simplify the code.
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lookup_page_cgroup() is usually used only against pages that are used in
userspace.
The exception is the CONFIG_DEBUG_VM-only memcg check from the page
allocator: it can run on pages without page_cgroup descriptors allocated
when the pages are fed into the page allocator for the first time during
boot or memory hotplug.
Include the array check only when CONFIG_DEBUG_VM is set and save the
unnecessary check in production kernels.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To find the page corresponding to a certain page_cgroup, the pc->flags
encoded the node or section ID with the base array to compare the pc
pointer to.
Now that the per-memory cgroup LRU lists link page descriptors directly,
there is no longer any code that knows the struct page_cgroup of a PFN
but not the struct page.
[hughd@google.com: remove unused node/section info from pc->flags fix]
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that all code that operated on global per-zone LRU lists is
converted to operate on per-memory cgroup LRU lists instead, there is no
reason to keep the double-LRU scheme around any longer.
The pc->lru member is removed and page->lru is linked directly to the
per-memory cgroup LRU lists, which removes two pointers from a
descriptor that exists for every page frame in the system.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Ying Han <yinghan@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
warning: symbol 'swap_cgroup_ctrl' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the cgroup base was allocated with kmalloc, it was necessary to
annotate the variable with kmemleak_not_leak(). But because it has
recently been changed to be allocated with alloc_page() (which skips
kmemleak checks) causes a warning on boot up.
I was triggering this output:
allocated 8388608 bytes of page_cgroup
please try 'cgroup_disable=memory' option if you don't want memory cgroups
kmemleak: Trying to color unknown object at 0xf5840000 as Grey
Pid: 0, comm: swapper Not tainted 3.0.0-test #12
Call Trace:
[<c17e34e6>] ? printk+0x1d/0x1f^M
[<c10e2941>] paint_ptr+0x4f/0x78
[<c178ab57>] kmemleak_not_leak+0x58/0x7d
[<c108ae9f>] ? __rcu_read_unlock+0x9/0x7d
[<c1cdb462>] kmemleak_init+0x19d/0x1e9
[<c1cbf771>] start_kernel+0x346/0x3ec
[<c1cbf1b4>] ? loglevel+0x18/0x18
[<c1cbf0aa>] i386_start_kernel+0xaa/0xb0
After a bit of debugging I tracked the object 0xf840000 (and others) down
to the cgroup code. The change from allocating base with kmalloc to
alloc_page() has the base not calling kmemleak_alloc() which adds the
pointer to the object_tree_root, but kmemleak_not_leak() adds it to the
crt_early_log[] table. On kmemleak_init(), the entry is found in the
early_log[] but not the object_tree_root, and this error message is
displayed.
If alloc_page() fails then it defaults back to vmalloc() which still uses
the kmemleak_alloc() which makes us still need the kmemleak_not_leak()
call. The solution is to call the kmemleak_alloc() directly if the
alloc_page() succeeds.
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a539f3533b ("mm: add SECTION_ALIGN_UP() and
SECTION_ALIGN_DOWN() macro") introduced the SECTION_ALIGN_UP() and
SECTION_ALIGN_DOWN() macros. Use those macros to increase code
readability.
Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit a2c8990aed ("memsw: remove noswapaccount kernel parameter"),
Michal forgot to remove some left pieces of noswapaccount in the tree,
this patch removes them all.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 21a3c96468 ("memcg: allocate memory cgroup structures in local
nodes") makes page_cgroup allocation as NUMA aware. But that caused a
problem https://bugzilla.kernel.org/show_bug.cgi?id=36192.
The problem was getting a NID from invalid struct pages, which was not
initialized because it was out-of-node, out of [node_start_pfn,
node_end_pfn)
Now, with sparsemem, page_cgroup_init scans pfn from 0 to max_pfn. But
this may scan a pfn which is not on any node and can access memmap which
is not initialized.
This makes page_cgroup_init() for SPARSEMEM node aware and remove a code
to get nid from page->flags. (Then, we'll use valid NID always.)
[akpm@linux-foundation.org: try to fix up comments]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move page-freeing code out of swap_cgroup_mutex in the hope that it could
reduce few of theoretical contentions between swapons and/or swapoffs.
This is just a cleanup, no functional changes.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It allocated one more page than necessary if @max_pages was a multiple of
SC_PER_PAGE.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit ca371c0d7e ("memcg: fix page_cgroup fatal error in FLATMEM")
removes call to alloc_bootmem() in the function so that it can be marked
as __meminit to reduce memory usage when MEMORY_HOTPLUG=n.
Also as the new helper function alloc_page_cgroup() is called only in the
function, it should be marked too.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit dde79e005a ("page_cgroup: reduce allocation overhead for
page_cgroup array for CONFIG_SPARSEMEM") added a regression that the
memory cgroup data structures all end up in node 0 because the first
attempt at allocating them would not pass in a node hint. Since the
initialization runs on CPU #0 it would all end up node 0. This is a
problem on large memory systems, where node 0 would lose a lot of
memory.
Change the alloc_pages_exact() to alloc_pages_exact_nid(). This will
still fall back to other nodes if not enough memory is available.
[ RED-PEN: right now it would fall back first before trying
vmalloc_node. Probably not the best strategy ... But I left it like
that for now. ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reported-by: Doug Nelson
Cc: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KAMEZAWA Hiroyuki noted that free_pages_cgroup doesn't have to check for
PageReserved because we never store the array on reserved pages (neither
alloc_pages_exact nor vmalloc use those pages).
So we can replace the check by a BUG_ON.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we are allocating a single page_cgroup array per memory section
(stored in mem_section->base) when CONFIG_SPARSEMEM is selected. This is
correct but memory inefficient solution because the allocated memory
(unless we fall back to vmalloc) is not kmalloc friendly:
- 32b - 16384 entries (20B per entry) fit into 327680B so the
524288B slab cache is used
- 32b with PAE - 131072 entries with 2621440B fit into 4194304B
- 64b - 32768 entries (40B per entry) fit into 2097152 cache
This is ~37% wasted space per memory section and it sumps up for the whole
memory. On a x86_64 machine it is something like 6MB per 1GB of RAM.
We can reduce the internal fragmentation by using alloc_pages_exact which
allocates PAGE_SIZE aligned blocks so we will get down to <4kB wasted
memory per section which is much better.
We still need a fallback to vmalloc because we have no guarantees that we
will have a continuous memory of that size (order-10) later on during the
hotplug events.
[hannes@cmpxchg.org: do not define unused free_page_cgroup() without memory hotplug]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In struct page_cgroup, we have a full word for flags but only a few are
reserved. Use the remaining upper bits to encode, depending on
configuration, the node or the section, to enable page_cgroup-to-page
lookups without a direct pointer.
This saves a full word for every page in a system with memory cgroups
enabled.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While looking at some other notifier callbacks I noticed this code could
use a simple cleanup.
notifier_from_errno() no longer needs the if (ret)/else conditional. That
same conditional is now done in notifier_from_errno().
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The pointer to the page_cgroup table allocated in
init_section_page_cgroup() is stored in section->page_cgroup as (base -
pfn). Since this value does not point to the beginning or inside the
allocated memory block, kmemleak reports a false positive.
This was reported in bugzilla.kernel.org as #16297.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Adrien Dessemond <adrien.dessemond@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
swap_cgroup uses 2bytes data and uses cmpxchg in a new operation. 2byte
cmpxchg/xchg is not available on some archs. This patch replaces
cmpxchg/xchg with operations under lock.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reported-by: Sachin Sant <sachinp@in.ibm.com> wrote:
Acked-by: Balbir Singh <balbir@in.ibm.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is another core part of this move-charge-at-task-migration
feature. It enables moving charges of anonymous swaps.
To move the charge of swap, we need to exchange swap_cgroup's record.
In current implementation, swap_cgroup's record is protected by:
- page lock: if the entry is on swap cache.
- swap_lock: if the entry is not on swap cache.
This works well in usual swap-in/out activity.
But this behavior make the feature of moving swap charge check many
conditions to exchange swap_cgroup's record safely.
So I changed modification of swap_cgroup's recored(swap_cgroup_record())
to use xchg, and define a new function to cmpxchg swap_cgroup's record.
This patch also enables moving charge of non pte_present but not uncharged
swap caches, which can be exist on swap-out path, by getting the target
pages via find_get_page() as do_mincore() does.
[kosaki.motohiro@jp.fujitsu.com: fix ia64 build]
[akpm@linux-foundation.org: fix typos]
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To initialize hotadded node, some pages are allocated. At that time, the
node hasn't memory, this makes the allocation always fail. In such case,
let's allocate pages from other nodes.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Yakui Zhao <yakui.zhao@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't need to check do_swap_account in the case that the function which
checks do_swap_account will never get called if do_swap_account == 0.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add file RSS tracking per memory cgroup
We currently don't track file RSS, the RSS we report is actually anon RSS.
All the file mapped pages, come in through the page cache and get
accounted there. This patch adds support for accounting file RSS pages.
It should
1. Help improve the metrics reported by the memory resource controller
2. Will form the basis for a future shared memory accounting heuristic
that has been proposed by Kamezawa.
Unfortunately, we cannot rename the existing "rss" keyword used in
memory.stat to "anon_rss". We however, add "mapped_file" data and hope to
educate the end user through documentation.
[hugh.dickins@tiscali.co.uk: fix mem_cgroup_update_mapped_file_stat oops]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix some cgroup messages to read better.
Update MAINTAINERS to include mm/*cgroup* files.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, SLAB is configured in very early stage and it can be used in
init routine now.
But replacing alloc_bootmem() in FLAT/DISCONTIGMEM's page_cgroup()
initialization breaks the allocation, now.
(Works well in SPARSEMEM case...it supports MEMORY_HOTPLUG and
size of page_cgroup is in reasonable size (< 1 << MAX_ORDER.)
This patch revive FLATMEM+memory cgroup by using alloc_bootmem.
In future,
We stop to support FLATMEM (if no users) or rewrite codes for flatmem
completely.But this will adds more messy codes and overheads.
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
The bootmem allocator is no longer available for page_cgroup_init() because we
set up the kernel slab allocator much earlier now.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
It's pointed out that swap_cgroup's message at swapon() is nonsense.
Because
* It can be calculated very easily if all necessary information is
written in Kconfig.
* It's not necessary to annoying people at every swapon().
In other view, now, memory usage per swp_entry is reduced to 2bytes from
8bytes(64bit) and I think it's reasonably small.
Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Try to use CSS ID for records in swap_cgroup. By this, on 64bit machine,
size of swap_cgroup goes down to 2 bytes from 8bytes.
This means, when 2GB of swap is equipped, (assume the page size is 4096bytes)
From size of swap_cgroup = 2G/4k * 8 = 4Mbytes.
To size of swap_cgroup = 2G/4k * 2 = 1Mbytes.
Reduction is large. Of course, there are trade-offs. This CSS ID will
add overhead to swap-in/swap-out/swap-free.
But in general,
- swap is a resource which the user tend to avoid use.
- If swap is never used, swap_cgroup area is not used.
- Reading traditional manuals, size of swap should be proportional to
size of memory. Memory size of machine is increasing now.
I think reducing size of swap_cgroup makes sense.
Note:
- ID->CSS lookup routine has no locks, it's under RCU-Read-Side.
- memcg can be obsolete at rmdir() but not freed while refcnt from
swap_cgroup is available.
Changelog v4->v5:
- reworked on to memcg-charge-swapcache-to-proper-memcg.patch
Changlog ->v4:
- fixed not configured case.
- deleted unnecessary comments.
- fixed NULL pointer bug.
- fixed message in dmesg.
[nishimura@mxp.nes.nec.co.jp: css_tryget can be called twice in !PageCgroupUsed case]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page_cgroup's page allocation at init/memory hotplug uses kmalloc() and
vmalloc(). If kmalloc() failes, vmalloc() is used.
This is because vmalloc() is very limited resource on 32bit systems.
We want to use kmalloc() first.
But in this kind of call, __GFP_NOWARN should be specified.
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We check mem_cgroup is disabled or not by checking
mem_cgroup_subsys.disabled. I think it has more references than expected,
now.
replacing
if (mem_cgroup_subsys.disabled)
with
if (mem_cgroup_disabled())
give us good look, I think.
[kamezawa.hiroyu@jp.fujitsu.com: fix typo]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A big patch for changing memcg's LRU semantics.
Now,
- page_cgroup is linked to mem_cgroup's its own LRU (per zone).
- LRU of page_cgroup is not synchronous with global LRU.
- page and page_cgroup is one-to-one and statically allocated.
- To find page_cgroup is on what LRU, you have to check pc->mem_cgroup as
- lru = page_cgroup_zoneinfo(pc, nid_of_pc, zid_of_pc);
- SwapCache is handled.
And, when we handle LRU list of page_cgroup, we do following.
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc); .....................(1)
mz = page_cgroup_zoneinfo(pc);
spin_lock(&mz->lru_lock);
.....add to LRU
spin_unlock(&mz->lru_lock);
unlock_page_cgroup(pc);
But (1) is spin_lock and we have to be afraid of dead-lock with zone->lru_lock.
So, trylock() is used at (1), now. Without (1), we can't trust "mz" is correct.
This is a trial to remove this dirty nesting of locks.
This patch changes mz->lru_lock to be zone->lru_lock.
Then, above sequence will be written as
spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU
mem_cgroup_add/remove/etc_lru() {
pc = lookup_page_cgroup(page);
mz = page_cgroup_zoneinfo(pc);
if (PageCgroupUsed(pc)) {
....add to LRU
}
spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU
This is much simpler.
(*) We're safe even if we don't take lock_page_cgroup(pc). Because..
1. When pc->mem_cgroup can be modified.
- at charge.
- at account_move().
2. at charge
the PCG_USED bit is not set before pc->mem_cgroup is fixed.
3. at account_move()
the page is isolated and not on LRU.
Pros.
- easy for maintenance.
- memcg can make use of laziness of pagevec.
- we don't have to duplicated LRU/Active/Unevictable bit in page_cgroup.
- LRU status of memcg will be synchronized with global LRU's one.
- # of locks are reduced.
- account_move() is simplified very much.
Cons.
- may increase cost of LRU rotation.
(no impact if memcg is not configured.)
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For accounting swap, we need a record per swap entry, at least.
This patch adds following function.
- swap_cgroup_swapon() .... called from swapon
- swap_cgroup_swapoff() ... called at the end of swapoff.
- swap_cgroup_record() .... record information of swap entry.
- swap_cgroup_lookup() .... lookup information of swap entry.
This patch just implements "how to record information". No actual method
for limit the usage of swap. These routine uses flat table to record and
lookup. "wise" lookup system like radix-tree requires requires memory
allocation at new records but swap-out is usually called under memory
shortage (or memcg hits limit.) So, I used static allocation. (maybe
dynamic allocation is not very hard but it adds additional memory
allocation in memory shortage path.)
Note1: In this, we use pointer to record information and this means
8bytes per swap entry. I think we can reduce this when we
create "id of cgroup" in the range of 0-65535 or 0-255.
Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: Hugh Dickins <hugh@veritas.com>
Reported-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In init_section_page_cgroup() the section a given pfn belongs to is
calculated at the top of the function and, despite the fact that the
pfn/section correspondence does not change, it is recalculated further
down the same function. By computing this just once and reusing that
value we save some bytes in the object file and do not waste CPU cycles.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sparse output following warning.
mm/page_cgroup.c💯15: warning: symbol 'init_section_page_cgroup' was
not declared. Should it be static?
cleanup here.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a total bootup freeze on ia64.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes for memcg/memory hotplug.
While memory hotplug allocate/free memmap, page_cgroup doesn't free
page_cgroup at OFFLINE when page_cgroup is allocated via bootomem.
(Because freeing bootmem requires special care.)
Then, if page_cgroup is allocated by bootmem and memmap is freed/allocated
by memory hotplug, page_cgroup->page == page is no longer true.
But current MEM_ONLINE handler doesn't check it and update
page_cgroup->page if it's not necessary to allocate page_cgroup. (This
was not found because memmap is not freed if SPARSEMEM_VMEMMAP is y.)
And I noticed that MEM_ONLINE can be called against "part of section".
So, freeing page_cgroup at CANCEL_ONLINE will cause trouble. (freeing
used page_cgroup) Don't rollback at CANCEL.
One more, current memory hotplug notifier is stopped by slub because it
sets NOTIFY_STOP_MASK to return vaule. So, page_cgroup's callback never
be called. (low priority than slub now.)
I think this slub's behavior is not intentional(BUG). and fixes it.
Another way to be considered about page_cgroup allocation:
- free page_cgroup at OFFLINE even if it's from bootmem
and remove specieal handler. But it requires more changes.
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12041
Signed-off-by: KAMEZAWA Hiruyoki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Tested-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page_cgroup_init() is called from mem_cgroup_init(). But at this
point, we cannot call alloc_bootmem().
(and this caused panic at boot.)
This patch moves page_cgroup_init() to init/main.c.
Time table is following:
==
parse_args(). # we can trust mem_cgroup_subsys.disabled bit after this.
....
cgroup_init_early() # "early" init of cgroup.
....
setup_arch() # memmap is allocated.
...
page_cgroup_init();
mem_init(); # we cannot call alloc_bootmem after this.
....
cgroup_init() # mem_cgroup is initialized.
==
Before page_cgroup_init(), mem_map must be initialized. So,
I added page_cgroup_init() to init/main.c directly.
(*) maybe this is not very clean but
- cgroup_init_early() is too early
- in cgroup_init(), we have to use vmalloc instead of alloc_bootmem().
use of vmalloc area in x86-32 is important and we should avoid very large
vmalloc() in x86-32. So, we want to use alloc_bootmem() and added page_cgroup_init()
directly to init/main.c
[akpm@linux-foundation.org: remove unneeded/bad mem_cgroup_subsys declaration]
[akpm@linux-foundation.org: fix build]
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_cgroup.c: In function 'init_section_page_cgroup':
mm/page_cgroup.c:111: error: implicit declaration of function 'vmalloc_node'
mm/page_cgroup.c:111: warning: assignment makes pointer from integer without a cast
mm/page_cgroup.c: In function '__free_page_cgroup':
mm/page_cgroup.c:140: error: implicit declaration of function 'vfree'
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allocate all page_cgroup at boot and remove page_cgroup poitner from
struct page. This patch adds an interface as
struct page_cgroup *lookup_page_cgroup(struct page*)
All FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported.
Remove page_cgroup pointer reduces the amount of memory by
- 4 bytes per PAGE_SIZE.
- 8 bytes per PAGE_SIZE
if memory controller is disabled. (even if configured.)
On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory.
On my x86-64 server with 48GB of memory, this saves 96MB of memory.
I think this reduction makes sense.
By pre-allocation, kmalloc/kfree in charge/uncharge are removed.
This means
- we're not necessary to be afraid of kmalloc faiulre.
(this can happen because of gfp_mask type.)
- we can avoid calling kmalloc/kfree.
- we can avoid allocating tons of small objects which can be fragmented.
- we can know what amount of memory will be used for this extra-lru handling.
I added printk message as
"allocated %ld bytes of page_cgroup"
"please try cgroup_disable=memory option if you don't want"
maybe enough informative for users.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
