e5eba30388a2822a590c0cb9485d5e0181e456c5
1219 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Minchan Kim
|
39f5677232 |
mm: prevent double decrease of nr_reserved_highatomic
commit 4855e4a7f29d6d10b0b9c84e189c770c9a94e91e upstream.
There is race between page freeing and unreserved highatomic.
CPU 0 CPU 1
free_hot_cold_page
mt = get_pfnblock_migratetype
set_pcppage_migratetype(page, mt)
unreserve_highatomic_pageblock
spin_lock_irqsave(&zone->lock)
move_freepages_block
set_pageblock_migratetype(page)
spin_unlock_irqrestore(&zone->lock)
free_pcppages_bulk
__free_one_page(mt) <- mt is stale
By above race, a page on CPU 0 could go non-highorderatomic free list
since the pageblock's type is changed. By that, unreserve logic of
highorderatomic can decrease reserved count on a same pageblock severak
times and then it will make mismatch between nr_reserved_highatomic and
the number of reserved pageblock.
So, this patch verifies whether the pageblock is highatomic or not and
decrease the count only if the pageblock is highatomic.
Link: http://lkml.kernel.org/r/1476259429-18279-3-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
||
 Pavel Tatashin
|
87395eeb28 |
mm: discard memblock data later
commit 3010f876500f9ba921afaeccec30c45ca6584dc8 upstream.
There is existing use after free bug when deferred struct pages are
enabled:
The memblock_add() allocates memory for the memory array if more than
128 entries are needed. See comment in e820__memblock_setup():
* The bootstrap memblock region count maximum is 128 entries
* (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
* than that - so allow memblock resizing.
This memblock memory is freed here:
free_low_memory_core_early()
We access the freed memblock.memory later in boot when deferred pages
are initialized in this path:
deferred_init_memmap()
for_each_mem_pfn_range()
__next_mem_pfn_range()
type = &memblock.memory;
One possible explanation for why this use-after-free hasn't been hit
before is that the limit of INIT_MEMBLOCK_REGIONS has never been
exceeded at least on systems where deferred struct pages were enabled.
Tested by reducing INIT_MEMBLOCK_REGIONS down to 4 from the current 128,
and verifying in qemu that this code is getting excuted and that the
freed pages are sane.
Link: http://lkml.kernel.org/r/1502485554-318703-2-git-send-email-pasha.tatashin@oracle.com
Fixes:
|
||
 Jonathan Toppins
|
b56cd77c12 |
mm: ratelimit PFNs busy info message
commit 75dddef32514f7aa58930bde6a1263253bc3d4ba upstream. The RDMA subsystem can generate several thousand of these messages per second eventually leading to a kernel crash. Ratelimit these messages to prevent this crash. Doug said: "I've been carrying a version of this for several kernel versions. I don't remember when they started, but we have one (and only one) class of machines: Dell PE R730xd, that generate these errors. When it happens, without a rate limit, we get rcu timeouts and kernel oopses. With the rate limit, we just get a lot of annoying kernel messages but the machine continues on, recovers, and eventually the memory operations all succeed" And: "> Well... why are all these EBUSY's occurring? It sounds inefficient > (at least) but if it is expected, normal and unavoidable then > perhaps we should just remove that message altogether? I don't have an answer to that question. To be honest, I haven't looked real hard. We never had this at all, then it started out of the blue, but only on our Dell 730xd machines (and it hits all of them), but no other classes or brands of machines. And we have our 730xd machines loaded up with different brands and models of cards (for instance one dedicated to mlx4 hardware, one for qib, one for mlx5, an ocrdma/cxgb4 combo, etc), so the fact that it hit all of the machines meant it wasn't tied to any particular brand/model of RDMA hardware. To me, it always smelled of a hardware oddity specific to maybe the CPUs or mainboard chipsets in these machines, so given that I'm not an mm expert anyway, I never chased it down. A few other relevant details: it showed up somewhere around 4.8/4.9 or thereabouts. It never happened before, but the prinkt has been there since the 3.18 days, so possibly the test to trigger this message was changed, or something else in the allocator changed such that the situation started happening on these machines? And, like I said, it is specific to our 730xd machines (but they are all identical, so that could mean it's something like their specific ram configuration is causing the allocator to hit this on these machine but not on other machines in the cluster, I don't want to say it's necessarily the model of chipset or CPU, there are other bits of identicalness between these machines)" Link: http://lkml.kernel.org/r/499c0f6cc10d6eb829a67f2a4d75b4228a9b356e.1501695897.git.jtoppins@redhat.com Signed-off-by: Jonathan Toppins <jtoppins@redhat.com> Reviewed-by: Doug Ledford <dledford@redhat.com> Tested-by: Doug Ledford <dledford@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
 Ard Biesheuvel
|
22cccef1fc |
mm: don't dereference struct page fields of invalid pages
[ Upstream commit f073bdc51771f5a5c7a8d1191bfc3ae371d44de7 ] The VM_BUG_ON() check in move_freepages() checks whether the node id of a page matches the node id of its zone. However, it does this before having checked whether the struct page pointer refers to a valid struct page to begin with. This is guaranteed in most cases, but may not be the case if CONFIG_HOLES_IN_ZONE=y. So reorder the VM_BUG_ON() with the pfn_valid_within() check. Link: http://lkml.kernel.org/r/1481706707-6211-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Hanjun Guo <hanjun.guo@linaro.org> Cc: Yisheng Xie <xieyisheng1@huawei.com> Cc: Robert Richter <rrichter@cavium.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
 Josh Poimboeuf
|
7b95b74563 |
mm/page_alloc: Remove kernel address exposure in free_reserved_area()
commit adb1fe9ae2ee6ef6bc10f3d5a588020e7664dfa7 upstream. Linus suggested we try to remove some of the low-hanging fruit related to kernel address exposure in dmesg. The only leaks I see on my local system are: Freeing SMP alternatives memory: 32K (ffffffff9e309000 - ffffffff9e311000) Freeing initrd memory: 10588K (ffffa0b736b42000 - ffffa0b737599000) Freeing unused kernel memory: 3592K (ffffffff9df87000 - ffffffff9e309000) Freeing unused kernel memory: 1352K (ffffa0b7288ae000 - ffffa0b728a00000) Freeing unused kernel memory: 632K (ffffa0b728d62000 - ffffa0b728e00000) Linus says: "I suspect we should just remove [the addresses in the 'Freeing' messages]. I'm sure they are useful in theory, but I suspect they were more useful back when the whole "free init memory" was originally done. These days, if we have a use-after-free, I suspect the init-mem situation is the easiest situation by far. Compared to all the dynamic allocations which are much more likely to show it anyway. So having debug output for that case is likely not all that productive." With this patch the freeing messages now look like this: Freeing SMP alternatives memory: 32K Freeing initrd memory: 10588K Freeing unused kernel memory: 3592K Freeing unused kernel memory: 1352K Freeing unused kernel memory: 632K Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/6836ff90c45b71d38e5d4405aec56fa9e5d1d4b2.1477405374.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
 Michal Hocko
|
292f70cd96 |
mm: consider memblock reservations for deferred memory initialization sizing
commit 864b9a393dcb5aed09b8fd31b9bbda0fdda99374 upstream.
We have seen an early OOM killer invocation on ppc64 systems with
crashkernel=4096M:
kthreadd invoked oom-killer: gfp_mask=0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK), nodemask=7, order=0, oom_score_adj=0
kthreadd cpuset=/ mems_allowed=7
CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.4.68-1.gd7fe927-default #1
Call Trace:
dump_stack+0xb0/0xf0 (unreliable)
dump_header+0xb0/0x258
out_of_memory+0x5f0/0x640
__alloc_pages_nodemask+0xa8c/0xc80
kmem_getpages+0x84/0x1a0
fallback_alloc+0x2a4/0x320
kmem_cache_alloc_node+0xc0/0x2e0
copy_process.isra.25+0x260/0x1b30
_do_fork+0x94/0x470
kernel_thread+0x48/0x60
kthreadd+0x264/0x330
ret_from_kernel_thread+0x5c/0xa4
Mem-Info:
active_anon:0 inactive_anon:0 isolated_anon:0
active_file:0 inactive_file:0 isolated_file:0
unevictable:0 dirty:0 writeback:0 unstable:0
slab_reclaimable:5 slab_unreclaimable:73
mapped:0 shmem:0 pagetables:0 bounce:0
free:0 free_pcp:0 free_cma:0
Node 7 DMA free:0kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:52428800kB managed:110016kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:320kB slab_unreclaimable:4672kB kernel_stack:1152kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
lowmem_reserve[]: 0 0 0 0
Node 7 DMA: 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 0kB
0 total pagecache pages
0 pages in swap cache
Swap cache stats: add 0, delete 0, find 0/0
Free swap = 0kB
Total swap = 0kB
819200 pages RAM
0 pages HighMem/MovableOnly
817481 pages reserved
0 pages cma reserved
0 pages hwpoisoned
the reason is that the managed memory is too low (only 110MB) while the
rest of the the 50GB is still waiting for the deferred intialization to
be done. update_defer_init estimates the initial memoty to initialize
to 2GB at least but it doesn't consider any memory allocated in that
range. In this particular case we've had
Reserving 4096MB of memory at 128MB for crashkernel (System RAM: 51200MB)
so the low 2GB is mostly depleted.
Fix this by considering memblock allocations in the initial static
initialization estimation. Move the max_initialise to
reset_deferred_meminit and implement a simple memblock_reserved_memory
helper which iterates all reserved blocks and sums the size of all that
start below the given address. The cumulative size is than added on top
of the initial estimation. This is still not ideal because
reset_deferred_meminit doesn't consider holes and so reservation might
be above the initial estimation whihch we ignore but let's make the
logic simpler until we really need to handle more complicated cases.
Fixes:
|
||
 Vlastimil Babka
|
4e434d4fe2 |
mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC
commit 62be1511b1db8066220b18b7d4da2e6b9fdc69fb upstream. Patch series "more robust PF_MEMALLOC handling" This series aims to unify the setting and clearing of PF_MEMALLOC, which prevents recursive reclaim. There are some places that clear the flag unconditionally from current->flags, which may result in clearing a pre-existing flag. This already resulted in a bug report that Patch 1 fixes (without the new helpers, to make backporting easier). Patch 2 introduces the new helpers, modelled after existing memalloc_noio_* and memalloc_nofs_* helpers, and converts mm core to use them. Patches 3 and 4 convert non-mm code. This patch (of 4): __alloc_pages_direct_compact() sets PF_MEMALLOC to prevent deadlock during page migration by lock_page() (see the comment in __unmap_and_move()). Then it unconditionally clears the flag, which can clear a pre-existing PF_MEMALLOC flag and result in recursive reclaim. This was not a problem until commit |
||
 Alexander Polakov
|
e3b08ebe47 |
mm/page_alloc.c: fix print order in show_free_areas()
commit 1f06b81aea5ecba2c1f8afd87e0ba1b9f8f90160 upstream.
Fixes:
|
||
 Gavin Shan
|
d1e8042628 |
mm/page_alloc: fix nodes for reclaim in fast path
commit e02dc017c3032dcdce1b993af0db135462e1b4b7 upstream.
When @node_reclaim_node isn't 0, the page allocator tries to reclaim
pages if the amount of free memory in the zones are below the low
watermark. On Power platform, none of NUMA nodes are scanned for page
reclaim because no nodes match the condition in zone_allows_reclaim().
On Power platform, RECLAIM_DISTANCE is set to 10 which is the distance
of Node-A to Node-A. So the preferred node even won't be scanned for
page reclaim.
__alloc_pages_nodemask()
get_page_from_freelist()
zone_allows_reclaim()
Anton proposed the test code as below:
# cat alloc.c
:
int main(int argc, char *argv[])
{
void *p;
unsigned long size;
unsigned long start, end;
start = time(NULL);
size = strtoul(argv[1], NULL, 0);
printf("To allocate %ldGB memory\n", size);
size <<= 30;
p = malloc(size);
assert(p);
memset(p, 0, size);
end = time(NULL);
printf("Used time: %ld seconds\n", end - start);
sleep(3600);
return 0;
}
The system I use for testing has two NUMA nodes. Both have 128GB
memory. In below scnario, the page caches on node#0 should be reclaimed
when it encounters pressure to accommodate request of allocation.
# echo 2 > /proc/sys/vm/zone_reclaim_mode; \
sync; \
echo 3 > /proc/sys/vm/drop_caches; \
# taskset -c 0 cat file.32G > /dev/null; \
grep FilePages /sys/devices/system/node/node0/meminfo
Node 0 FilePages: 33619712 kB
# taskset -c 0 ./alloc 128
# grep FilePages /sys/devices/system/node/node0/meminfo
Node 0 FilePages: 33619840 kB
# grep MemFree /sys/devices/system/node/node0/meminfo
Node 0 MemFree: 186816 kB
With the patch applied, the pagecache on node-0 is reclaimed when its
free memory is running out. It's the expected behaviour.
# echo 2 > /proc/sys/vm/zone_reclaim_mode; \
sync; \
echo 3 > /proc/sys/vm/drop_caches
# taskset -c 0 cat file.32G > /dev/null; \
grep FilePages /sys/devices/system/node/node0/meminfo
Node 0 FilePages: 33605568 kB
# taskset -c 0 ./alloc 128
# grep FilePages /sys/devices/system/node/node0/meminfo
Node 0 FilePages: 1379520 kB
# grep MemFree /sys/devices/system/node/node0/meminfo
Node 0 MemFree: 317120 kB
Fixes:
|
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|
Vlastimil Babka
|
96e5cec10e |
mm, page_alloc: fix premature OOM when racing with cpuset mems update
commit e47483bca2cc59a4593b37a270b16ee42b1d9f08 upstream. Ganapatrao Kulkarni reported that the LTP test cpuset01 in stress mode triggers OOM killer in few seconds, despite lots of free memory. The test attempts to repeatedly fault in memory in one process in a cpuset, while changing allowed nodes of the cpuset between 0 and 1 in another process. The problem comes from insufficient protection against cpuset changes, which can cause get_page_from_freelist() to consider all zones as non-eligible due to nodemask and/or current->mems_allowed. This was masked in the past by sufficient retries, but since commit |
||
|
Vlastimil Babka
|
b678e4ff7c |
mm, page_alloc: move cpuset seqcount checking to slowpath
commit 5ce9bfef1d27944c119a397a9d827bef795487ce upstream. This is a preparation for the following patch to make review simpler. While the primary motivation is a bug fix, this also simplifies the fast path, although the moved code is only enabled when cpusets are in use. Link: http://lkml.kernel.org/r/20170120103843.24587-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Ganapatrao Kulkarni <gpkulkarni@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Vlastimil Babka
|
d1656c5aef |
mm, page_alloc: fix fast-path race with cpuset update or removal
commit 16096c25bf0ca5d87e4fa6ec6108ba53feead212 upstream.
Ganapatrao Kulkarni reported that the LTP test cpuset01 in stress mode
triggers OOM killer in few seconds, despite lots of free memory. The
test attempts to repeatedly fault in memory in one process in a cpuset,
while changing allowed nodes of the cpuset between 0 and 1 in another
process.
One possible cause is that in the fast path we find the preferred
zoneref according to current mems_allowed, so that it points to the
middle of the zonelist, skipping e.g. zones of node 1 completely. If
the mems_allowed is updated to contain only node 1, we never reach it in
the zonelist, and trigger OOM before checking the cpuset_mems_cookie.
This patch fixes the particular case by redoing the preferred zoneref
search if we switch back to the original nodemask. The condition is
also slightly changed so that when the last non-root cpuset is removed,
we don't miss it.
Note that this is not a full fix, and more patches will follow.
Link: http://lkml.kernel.org/r/20170120103843.24587-3-vbabka@suse.cz
Fixes:
|
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|
Vlastimil Babka
|
ade7afe9dc |
mm, page_alloc: fix check for NULL preferred_zone
commit ea57485af8f4221312a5a95d63c382b45e7840dc upstream. Patch series "fix premature OOM regression in 4.7+ due to cpuset races". This is v2 of my attempt to fix the recent report based on LTP cpuset stress test [1]. The intention is to go to stable 4.9 LTSS with this, as triggering repeated OOMs is not nice. That's why the patches try to be not too intrusive. Unfortunately why investigating I found that modifying the testcase to use per-VMA policies instead of per-task policies will bring the OOM's back, but that seems to be much older and harder to fix problem. I have posted a RFC [2] but I believe that fixing the recent regressions has a higher priority. Longer-term we might try to think how to fix the cpuset mess in a better and less error prone way. I was for example very surprised to learn, that cpuset updates change not only task->mems_allowed, but also nodemask of mempolicies. Until now I expected the parameter to alloc_pages_nodemask() to be stable. I wonder why do we then treat cpusets specially in get_page_from_freelist() and distinguish HARDWALL etc, when there's unconditional intersection between mempolicy and cpuset. I would expect the nodemask adjustment for saving overhead in g_p_f(), but that clearly doesn't happen in the current form. So we have both crazy complexity and overhead, AFAICS. [1] https://lkml.kernel.org/r/CAFpQJXUq-JuEP=QPidy4p_=FN0rkH5Z-kfB4qBvsf6jMS87Edg@mail.gmail.com [2] https://lkml.kernel.org/r/7c459f26-13a6-a817-e508-b65b903a8378@suse.cz This patch (of 4): Since commit |
||
 Mel Gorman
|
44919a2ac4 |
mm, page_alloc: keep pcp count and list contents in sync if struct page is corrupted
commit a6de734bc002fe2027ccc074fbbd87d72957b7a4 upstream. Vlastimil Babka pointed out that commit |
||
 Tetsuo Handa
|
9e80c719a8 |
mm: remove extra newline from allocation stall warning
Commit
|
||
 Linus Torvalds
|
577f12c07e |
Merge tag 'gcc-plugins-v4.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugin fixes from Kees Cook: - make sure required exports from gcc plugins are visible to gcc - switch latent_entropy to unsigned long to avoid stack frame bloat * tag 'gcc-plugins-v4.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: latent_entropy: Fix wrong gcc code generation with 64 bit variables gcc-plugins: Export symbols needed by gcc |
||
 Kees Cook
|
58bea4144d |
latent_entropy: Fix wrong gcc code generation with 64 bit variables
The stack frame size could grow too large when the plugin used long long on 32-bit architectures when the given function had too many basic blocks. The gcc warning was: drivers/pci/hotplug/ibmphp_ebda.c: In function 'ibmphp_access_ebda': drivers/pci/hotplug/ibmphp_ebda.c:409:1: warning: the frame size of 1108 bytes is larger than 1024 bytes [-Wframe-larger-than=] This switches latent_entropy from u64 to unsigned long. Thanks to PaX Team and Emese Revfy for the patch. Signed-off-by: Kees Cook <keescook@chromium.org> |
||
 Joe Perches
|
1f84a18fc0 |
mm: page_alloc: use KERN_CONT where appropriate
Recent changes to printk require KERN_CONT uses to continue logging
messages. So add KERN_CONT where necessary.
[akpm@linux-foundation.org: coding-style fixes]
Fixes:
|
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|
Linus Torvalds
|
9dcb8b685f |
mm: remove per-zone hashtable of bitlock waitqueues
The per-zone waitqueues exist because of a scalability issue with the
page waitqueues on some NUMA machines, but it turns out that they hurt
normal loads, and now with the vmalloced stacks they also end up
breaking gfs2 that uses a bit_wait on a stack object:
wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE)
where 'gh' can be a reference to the local variable 'mount_gh' on the
stack of fill_super().
The reason the per-zone hash table breaks for this case is that there is
no "zone" for virtual allocations, and trying to look up the physical
page to get at it will fail (with a BUG_ON()).
It turns out that I actually complained to the mm people about the
per-zone hash table for another reason just a month ago: the zone lookup
also hurts the regular use of "unlock_page()" a lot, because the zone
lookup ends up forcing several unnecessary cache misses and generates
horrible code.
As part of that earlier discussion, we had a much better solution for
the NUMA scalability issue - by just making the page lock have a
separate contention bit, the waitqueue doesn't even have to be looked at
for the normal case.
Peter Zijlstra already has a patch for that, but let's see if anybody
even notices. In the meantime, let's fix the actual gfs2 breakage by
simplifying the bitlock waitqueues and removing the per-zone issue.
Reported-by: Andreas Gruenbacher <agruenba@redhat.com>
Tested-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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|
Linus Torvalds
|
9ffc66941d |
Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins update from Kees Cook: "This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals" * tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: latent_entropy: Mark functions with __latent_entropy gcc-plugins: Add latent_entropy plugin |
||
 Emese Revfy
|
0766f788eb |
latent_entropy: Mark functions with __latent_entropy
The __latent_entropy gcc attribute can be used only on functions and variables. If it is on a function then the plugin will instrument it for gathering control-flow entropy. If the attribute is on a variable then the plugin will initialize it with random contents. The variable must be an integer, an integer array type or a structure with integer fields. These specific functions have been selected because they are init functions (to help gather boot-time entropy), are called at unpredictable times, or they have variable loops, each of which provide some level of latent entropy. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message] Signed-off-by: Kees Cook <keescook@chromium.org> |
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Emese Revfy
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38addce8b6 |
gcc-plugins: Add latent_entropy plugin
This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals. The need for very-early boot entropy tends to be very architecture or system design specific, so this plugin is more suited for those sorts of special cases. The existing kernel RNG already attempts to extract entropy from reliable runtime variation, but this plugin takes the idea to a logical extreme by permuting a global variable based on any variation in code execution (e.g. a different value (and permutation function) is used to permute the global based on loop count, case statement, if/then/else branching, etc). To do this, the plugin starts by inserting a local variable in every marked function. The plugin then adds logic so that the value of this variable is modified by randomly chosen operations (add, xor and rol) and random values (gcc generates separate static values for each location at compile time and also injects the stack pointer at runtime). The resulting value depends on the control flow path (e.g., loops and branches taken). Before the function returns, the plugin mixes this local variable into the latent_entropy global variable. The value of this global variable is added to the kernel entropy pool in do_one_initcall() and _do_fork(), though it does not credit any bytes of entropy to the pool; the contents of the global are just used to mix the pool. Additionally, the plugin can pre-initialize arrays with build-time random contents, so that two different kernel builds running on identical hardware will not have the same starting values. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message and code comments] Signed-off-by: Kees Cook <keescook@chromium.org> |
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Michal Hocko
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63f53dea0c |
mm: warn about allocations which stall for too long
Currently we do warn only about allocation failures but small allocations are basically nofail and they might loop in the page allocator for a long time. Especially when the reclaim cannot make any progress - e.g. GFP_NOFS cannot invoke the oom killer and rely on a different context to make a forward progress in case there is a lot memory used by filesystems. Give us at least a clue when something like this happens and warn about allocations which take more than 10s. Print the basic allocation context information along with the cumulative time spent in the allocation as well as the allocation stack. Repeat the warning after every 10 seconds so that we know that the problem is permanent rather than ephemeral. Link: http://lkml.kernel.org/r/20160929084407.7004-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
|
7877cdcc38 |
mm: consolidate warn_alloc_failed users
warn_alloc_failed is currently used from the page and vmalloc allocators. This is a good reuse of the code except that vmalloc would appreciate a slightly different warning message. This is already handled by the fmt parameter except that "%s: page allocation failure: order:%u, mode:%#x(%pGg)" is printed anyway. This might be quite misleading because it might be a vmalloc failure which leads to the warning while the page allocator is not the culprit here. Fix this by always using the fmt string and only print the context that makes sense for the particular context (e.g. order makes only very little sense for the vmalloc context). Rename the function to not miss any user and also because a later patch will reuse it also for !failure cases. Link: http://lkml.kernel.org/r/20160929084407.7004-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vlastimil Babka
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423b452e15 |
mm, page_alloc: pull no_progress_loops update to should_reclaim_retry()
The should_reclaim_retry() makes decisions based on no_progress_loops, so it makes sense to also update the counter there. It will be also consistent with should_compact_retry() and compaction_retries. No functional change. [hillf.zj@alibaba-inc.com: fix missing pointer dereferences] Link: http://lkml.kernel.org/r/20160926162025.21555-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vlastimil Babka
|
c2033b00db |
mm, compaction: restrict full priority to non-costly orders
The new ultimate compaction priority disables some heuristics, which may result in excessive cost. This is fine for non-costly orders where we want to try hard before resulting for OOM, but might be disruptive for costly orders which do not trigger OOM and should generally have some fallback. Thus, we disable the full priority for costly orders. Suggested-by: Michal Hocko <mhocko@kernel.org> Link: http://lkml.kernel.org/r/20160906135258.18335-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vlastimil Babka
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d943649831 |
mm, compaction: more reliably increase direct compaction priority
During reclaim/compaction loop, compaction priority can be increased by the should_compact_retry() function, but the current code is not optimal. Priority is only increased when compaction_failed() is true, which means that compaction has scanned the whole zone. This may not happen even after multiple attempts with a lower priority due to parallel activity, so we might needlessly struggle on the lower priorities and possibly run out of compaction retry attempts in the process. After this patch we are guaranteed at least one attempt at the highest compaction priority even if we exhaust all retries at the lower priorities. Link: http://lkml.kernel.org/r/20160906135258.18335-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vlastimil Babka
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3250845d05 |
Revert "mm, oom: prevent premature OOM killer invocation for high order request"
Patch series "reintroduce compaction feedback for OOM decisions". After several people reported OOM's for order-2 allocations in 4.7 due to Michal Hocko's OOM rework, he reverted the part that considered compaction feedback [1] in the decisions to retry reclaim/compaction. This was to provide a fix quickly for 4.8 rc and 4.7 stable series, while mmotm had an almost complete solution that instead improved compaction reliability. This series completes the mmotm solution and reintroduces the compaction feedback into OOM decisions. The first two patches restore the state of mmotm before the temporary solution was merged, the last patch should be the missing piece for reliability. The third patch restricts the hardened compaction to non-costly orders, since costly orders don't result in OOMs in the first place. [1] http://marc.info/?i=20160822093249.GA14916%40dhcp22.suse.cz%3E This patch (of 4): Commit |
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 Srikar Dronamraju
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f6f34b4387 |
mm: introduce arch_reserved_kernel_pages()
Currently arch specific code can reserve memory blocks but alloc_large_system_hash() may not take it into consideration when sizing the hashes. This can lead to bigger hash than required and lead to no available memory for other purposes. This is specifically true for systems with CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled. One approach to solve this problem would be to walk through the memblock regions and calculate the available memory and base the size of hash system on the available memory. The other approach would be to depend on the architecture to provide the number of pages that are reserved. This change provides hooks to allow the architecture to provide the required info. Link: http://lkml.kernel.org/r/1472476010-4709-2-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Suggested-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Balbir Singh <bsingharora@gmail.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> |
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 Aneesh Kumar K.V
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c9634cf012 |
mm: use zonelist name instead of using hardcoded index
Use the existing enums instead of hardcoded index when looking at the zonelist. This makes it more readable. No functionality change by this patch. Link: http://lkml.kernel.org/r/1472227078-24852-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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 Joonsoo Kim
|
980ac1672e |
mm/page_ext: support extra space allocation by page_ext user
Until now, if some page_ext users want to use it's own field on
page_ext, it should be defined in struct page_ext by hard-coding. It
has a problem that wastes memory in following situation.
struct page_ext {
#ifdef CONFIG_A
int a;
#endif
#ifdef CONFIG_B
int b;
#endif
};
Assume that kernel is built with both CONFIG_A and CONFIG_B. Even if we
enable feature A and doesn't enable feature B at runtime, each entry of
struct page_ext takes two int rather than one int. It's undesirable
result so this patch tries to fix it.
To solve above problem, this patch implements to support extra space
allocation at runtime. When need() callback returns true, it's extra
memory requirement is summed to entry size of page_ext. Also, offset
for each user's extra memory space is returned. With this offset, user
can use this extra space and there is no need to define needed field on
page_ext by hard-coding.
This patch only implements an infrastructure. Following patch will use
it for page_owner which is only user having it's own fields on page_ext.
Link: http://lkml.kernel.org/r/1471315879-32294-6-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Joonsoo Kim
|
f1c1e9f7b5 |
mm/debug_pagealloc.c: don't allocate page_ext if we don't use guard page
What debug_pagealloc does is just mapping/unmapping page table. Basically, it doesn't need additional memory space to memorize something. But, with guard page feature, it requires additional memory to distinguish if the page is for guard or not. Guard page is only used when debug_guardpage_minorder is non-zero so this patch removes additional memory allocation (page_ext) if debug_guardpage_minorder is zero. It saves memory if we just use debug_pagealloc and not guard page. Link: http://lkml.kernel.org/r/1471315879-32294-3-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Joonsoo Kim
|
acbc15a4b3 |
mm/debug_pagealloc.c: clean-up guard page handling code
Patch series "Reduce memory waste by page extension user".
This patchset tries to reduce memory waste by page extension user.
First case is architecture supported debug_pagealloc. It doesn't
requires additional memory if guard page isn't used. 8 bytes per page
will be saved in this case.
Second case is related to page owner feature. Until now, if page_ext
users want to use it's own fields on page_ext, fields should be defined
in struct page_ext by hard-coding. It has a following problem.
struct page_ext {
#ifdef CONFIG_A
int a;
#endif
#ifdef CONFIG_B
int b;
#endif
};
Assume that kernel is built with both CONFIG_A and CONFIG_B. Even if we
enable feature A and doesn't enable feature B at runtime, each entry of
struct page_ext takes two int rather than one int. It's undesirable
waste so this patch tries to reduce it. By this patchset, we can save
20 bytes per page dedicated for page owner feature in some
configurations.
This patch (of 6):
We can make code clean by moving decision condition for set_page_guard()
into set_page_guard() itself. It will help code readability. There is
no functional change.
Link: http://lkml.kernel.org/r/1471315879-32294-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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 Xishi Qiu
|
e780149bcd |
mm: fix set pageblock migratetype in deferred struct page init
On x86_64 MAX_ORDER_NR_PAGES is usually 4M, and a pageblock is usually
2M, so we only set one pageblock's migratetype in deferred_free_range()
if pfn is aligned to MAX_ORDER_NR_PAGES. That means it causes
uninitialized migratetype blocks, you can see from "cat
/proc/pagetypeinfo", almost half blocks are Unmovable.
Also we missed freeing the last block in deferred_init_memmap(), it
causes memory leak.
Fixes:
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Xishi Qiu
|
e506b99696 |
mem-hotplug: fix node spanned pages when we have a movable node
Commit
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Vlastimil Babka
|
8348faf91f |
mm, compaction: require only min watermarks for non-costly orders
The __compaction_suitable() function checks the low watermark plus a compact_gap() gap to decide if there's enough free memory to perform compaction. Then __isolate_free_page uses low watermark check to decide if particular free page can be isolated. In the latter case, using low watermark is needlessly pessimistic, as the free page isolations are only temporary. For __compaction_suitable() the higher watermark makes sense for high-order allocations where more freepages increase the chance of success, and we can typically fail with some order-0 fallback when the system is struggling to reach that watermark. But for low-order allocation, forming the page should not be that hard. So using low watermark here might just prevent compaction from even trying, and eventually lead to OOM killer even if we are above min watermarks. So after this patch, we use min watermark for non-costly orders in __compaction_suitable(), and for all orders in __isolate_free_page(). [vbabka@suse.cz: clarify __isolate_free_page() comment] Link: http://lkml.kernel.org/r/7ae4baec-4eca-e70b-2a69-94bea4fb19fa@suse.cz Link: http://lkml.kernel.org/r/20160810091226.6709-11-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Lorenzo Stoakes <lstoakes@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vlastimil Babka
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984fdba6a3 |
mm, compaction: use proper alloc_flags in __compaction_suitable()
The __compaction_suitable() function checks the low watermark plus a compact_gap() gap to decide if there's enough free memory to perform compaction. This check uses direct compactor's alloc_flags, but that's wrong, since these flags are not applicable for freepage isolation. For example, alloc_flags may indicate access to memory reserves, making compaction proceed, and then fail watermark check during the isolation. A similar problem exists for ALLOC_CMA, which may be part of alloc_flags, but not during freepage isolation. In this case however it makes sense to use ALLOC_CMA both in __compaction_suitable() and __isolate_free_page(), since there's actually nothing preventing the freepage scanner to isolate from CMA pageblocks, with the assumption that a page that could be migrated once by compaction can be migrated also later by CMA allocation. Thus we should count pages in CMA pageblocks when considering compaction suitability and when isolating freepages. To sum up, this patch should remove some false positives from __compaction_suitable(), and allow compaction to proceed when free pages required for compaction reside in the CMA pageblocks. Link: http://lkml.kernel.org/r/20160810091226.6709-10-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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6aa303defb |
mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator
Firmware Assisted Dump (FA_DUMP) on ppc64 reserves substantial amounts
of memory when booting a secondary kernel. Srikar Dronamraju reported
that multiple nodes may have no memory managed by the buddy allocator
but still return true for populated_zone().
Commit
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Michal Hocko
|
6b4e3181d7 |
mm, oom: prevent premature OOM killer invocation for high order request
There have been several reports about pre-mature OOM killer invocation
in 4.7 kernel when order-2 allocation request (for the kernel stack)
invoked OOM killer even during basic workloads (light IO or even kernel
compile on some filesystems). In all reported cases the memory is
fragmented and there are no order-2+ pages available. There is usually
a large amount of slab memory (usually dentries/inodes) and further
debugging has shown that there are way too many unmovable blocks which
are skipped during the compaction. Multiple reporters have confirmed
that the current linux-next which includes [1] and [2] helped and OOMs
are not reproducible anymore.
A simpler fix for the late rc and stable is to simply ignore the
compaction feedback and retry as long as there is a reclaim progress and
we are not getting OOM for order-0 pages. We already do that for
CONFING_COMPACTION=n so let's reuse the same code when compaction is
enabled as well.
[1] http://lkml.kernel.org/r/20160810091226.6709-1-vbabka@suse.cz
[2] http://lkml.kernel.org/r/f7a9ea9d-bb88-bfd6-e340-3a933559305a@suse.cz
Fixes:
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Mel Gorman
|
2f95ff90b9 |
proc, meminfo: use correct helpers for calculating LRU sizes in meminfo
meminfo_proc_show() and si_mem_available() are using the wrong helpers for calculating the size of the LRUs. The user-visible impact is that there appears to be an abnormally high number of unevictable pages. Link: http://lkml.kernel.org/r/20160805105805.GR2799@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Joonsoo Kim
|
6423aa8192 |
mm/page_alloc.c: recalculate some of node threshold when on/offline memory
Some of node threshold depends on number of managed pages in the node. When memory is going on/offline, it can be changed and we need to adjust them. Add recalculation to appropriate places and clean-up related functions for better maintenance. Link: http://lkml.kernel.org/r/1470724248-26780-2-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Joonsoo Kim
|
81cbcbc2d8 |
mm/page_alloc.c: fix wrong initialization when sysctl_min_unmapped_ratio changes
Before resetting min_unmapped_pages, we need to initialize
min_unmapped_pages rather than min_slab_pages.
Fixes:
|
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 Vladimir Davydov
|
c4159a75b6 |
mm: memcontrol: only mark charged pages with PageKmemcg
To distinguish non-slab pages charged to kmemcg we mark them PageKmemcg,
which sets page->_mapcount to -512. Currently, we set/clear PageKmemcg
in __alloc_pages_nodemask()/free_pages_prepare() for any page allocated
with __GFP_ACCOUNT, including those that aren't actually charged to any
cgroup, i.e. allocated from the root cgroup context. To avoid overhead
in case cgroups are not used, we only do that if memcg_kmem_enabled() is
true. The latter is set iff there are kmem-enabled memory cgroups
(online or offline). The root cgroup is not considered kmem-enabled.
As a result, if a page is allocated with __GFP_ACCOUNT for the root
cgroup when there are kmem-enabled memory cgroups and is freed after all
kmem-enabled memory cgroups were removed, e.g.
# no memory cgroups has been created yet, create one
mkdir /sys/fs/cgroup/memory/test
# run something allocating pages with __GFP_ACCOUNT, e.g.
# a program using pipe
dmesg | tail
# remove the memory cgroup
rmdir /sys/fs/cgroup/memory/test
we'll get bad page state bug complaining about page->_mapcount != -1:
BUG: Bad page state in process swapper/0 pfn:1fd945c
page:ffffea007f651700 count:0 mapcount:-511 mapping: (null) index:0x0
flags: 0x1000000000000000()
To avoid that, let's mark with PageKmemcg only those pages that are
actually charged to and hence pin a non-root memory cgroup.
Fixes:
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Mel Gorman
|
b4911ea2bc |
mm: initialise per_cpu_nodestats for all online pgdats at boot
Paul Mackerras and Reza Arbab reported that machines with memoryless nodes fail when vmstats are refreshed. Paul reported an oops as follows Unable to handle kernel paging request for data at address 0xff7a10000 Faulting instruction address: 0xc000000000270cd0 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.7.0-kvm+ #118 task: c000000ff0680010 task.stack: c000000ff0704000 NIP: c000000000270cd0 LR: c000000000270ce8 CTR: 0000000000000000 REGS: c000000ff0707900 TRAP: 0300 Not tainted (4.7.0-kvm+) MSR: 9000000102009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE,TM[E]> CR: 846b6824 XER: 20000000 CFAR: c000000000008768 DAR: 0000000ff7a10000 DSISR: 42000000 SOFTE: 1 NIP refresh_zone_stat_thresholds+0x80/0x240 LR refresh_zone_stat_thresholds+0x98/0x240 Call Trace: refresh_zone_stat_thresholds+0xb8/0x240 (unreliable) Both supplied potential fixes but one potentially misses checks and another had redundant initialisations. This version initialises per_cpu_nodestats on a per-pgdat basis instead of on a per-zone basis. Link: http://lkml.kernel.org/r/20160804092404.GI2799@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Paul Mackerras <paulus@ozlabs.org> Reported-by: Reza Arbab <arbab@linux.vnet.ibm.com> Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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 Fabian Frederick
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bd721ea73e |
treewide: replace obsolete _refok by __ref
There was only one use of __initdata_refok and __exit_refok
__init_refok was used 46 times against 82 for __ref.
Those definitions are obsolete since commit
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Vlastimil Babka
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c3486f5376 |
mm, compaction: simplify contended compaction handling
Async compaction detects contention either due to failing trylock on
zone->lock or lru_lock, or by need_resched(). Since
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Vlastimil Babka
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a5508cd83f |
mm, compaction: introduce direct compaction priority
In the context of direct compaction, for some types of allocations we would like the compaction to either succeed or definitely fail while trying as hard as possible. Current async/sync_light migration mode is insufficient, as there are heuristics such as caching scanner positions, marking pageblocks as unsuitable or deferring compaction for a zone. At least the final compaction attempt should be able to override these heuristics. To communicate how hard compaction should try, we replace migration mode with a new enum compact_priority and change the relevant function signatures. In compact_zone_order() where struct compact_control is constructed, the priority is mapped to suitable control flags. This patch itself has no functional change, as the current priority levels are mapped back to the same migration modes as before. Expanding them will be done next. Note that !CONFIG_COMPACTION variant of try_to_compact_pages() is removed, as the only caller exists under CONFIG_COMPACTION. Link: http://lkml.kernel.org/r/20160721073614.24395-8-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vlastimil Babka
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2516035499 |
mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations
After the previous patch, we can distinguish costly allocations that
should be really lightweight, such as THP page faults, with
__GFP_NORETRY. This means we don't need to recognize khugepaged
allocations via PF_KTHREAD anymore. We can also change THP page faults
in areas where madvise(MADV_HUGEPAGE) was used to try as hard as
khugepaged, as the process has indicated that it benefits from THP's and
is willing to pay some initial latency costs.
We can also make the flags handling less cryptic by distinguishing
GFP_TRANSHUGE_LIGHT (no reclaim at all, default mode in page fault) from
GFP_TRANSHUGE (only direct reclaim, khugepaged default). Adding
__GFP_NORETRY or __GFP_KSWAPD_RECLAIM is done where needed.
The patch effectively changes the current GFP_TRANSHUGE users as
follows:
* get_huge_zero_page() - the zero page lifetime should be relatively
long and it's shared by multiple users, so it's worth spending some
effort on it. We use GFP_TRANSHUGE, and __GFP_NORETRY is not added.
This also restores direct reclaim to this allocation, which was
unintentionally removed by commit e4a49efe4e7e ("mm: thp: set THP defrag
by default to madvise and add a stall-free defrag option")
* alloc_hugepage_khugepaged_gfpmask() - this is khugepaged, so latency
is not an issue. So if khugepaged "defrag" is enabled (the default), do
reclaim via GFP_TRANSHUGE without __GFP_NORETRY. We can remove the
PF_KTHREAD check from page alloc.
As a side-effect, khugepaged will now no longer check if the initial
compaction was deferred or contended. This is OK, as khugepaged sleep
times between collapsion attempts are long enough to prevent noticeable
disruption, so we should allow it to spend some effort.
* migrate_misplaced_transhuge_page() - already was masking out
__GFP_RECLAIM, so just convert to GFP_TRANSHUGE_LIGHT which is
equivalent.
* alloc_hugepage_direct_gfpmask() - vma's with VM_HUGEPAGE (via madvise)
are now allocating without __GFP_NORETRY. Other vma's keep using
__GFP_NORETRY if direct reclaim/compaction is at all allowed (by default
it's allowed only for madvised vma's). The rest is conversion to
GFP_TRANSHUGE(_LIGHT).
[mhocko@suse.com: suggested GFP_TRANSHUGE_LIGHT]
Link: http://lkml.kernel.org/r/20160721073614.24395-7-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Vlastimil Babka
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3eb2771b06 |
mm, page_alloc: make THP-specific decisions more generic
Since THP allocations during page faults can be costly, extra decisions
are employed for them to avoid excessive reclaim and compaction, if the
initial compaction doesn't look promising. The detection has never been
perfect as there is no gfp flag specific to THP allocations. At this
moment it checks the whole combination of flags that makes up
GFP_TRANSHUGE, and hopes that no other users of such combination exist,
or would mind being treated the same way. Extra care is also taken to
separate allocations from khugepaged, where latency doesn't matter that
much.
It is however possible to distinguish these allocations in a simpler and
more reliable way. The key observation is that after the initial
compaction followed by the first iteration of "standard"
reclaim/compaction, both __GFP_NORETRY allocations and costly
allocations without __GFP_REPEAT are declared as failures:
/* Do not loop if specifically requested */
if (gfp_mask & __GFP_NORETRY)
goto nopage;
/*
* Do not retry costly high order allocations unless they are
* __GFP_REPEAT
*/
if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT))
goto nopage;
This means we can further distinguish allocations that are costly order
*and* additionally include the __GFP_NORETRY flag. As it happens,
GFP_TRANSHUGE allocations do already fall into this category. This will
also allow other costly allocations with similar high-order benefit vs
latency considerations to use this semantic. Furthermore, we can
distinguish THP allocations that should try a bit harder (such as from
khugepageed) by removing __GFP_NORETRY, as will be done in the next
patch.
Link: http://lkml.kernel.org/r/20160721073614.24395-6-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Vlastimil Babka
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a8161d1ed6 |
mm, page_alloc: restructure direct compaction handling in slowpath
The retry loop in __alloc_pages_slowpath is supposed to keep trying reclaim and compaction (and OOM), until either the allocation succeeds, or returns with failure. Success here is more probable when reclaim precedes compaction, as certain watermarks have to be met for compaction to even try, and more free pages increase the probability of compaction success. On the other hand, starting with light async compaction (if the watermarks allow it), can be more efficient, especially for smaller orders, if there's enough free memory which is just fragmented. Thus, the current code starts with compaction before reclaim, and to make sure that the last reclaim is always followed by a final compaction, there's another direct compaction call at the end of the loop. This makes the code hard to follow and adds some duplicated handling of migration_mode decisions. It's also somewhat inefficient that even if reclaim or compaction decides not to retry, the final compaction is still attempted. Some gfp flags combination also shortcut these retry decisions by "goto noretry;", making it even harder to follow. This patch attempts to restructure the code with only minimal functional changes. The call to the first compaction and THP-specific checks are now placed above the retry loop, and the "noretry" direct compaction is removed. The initial compaction is additionally restricted only to costly orders, as we can expect smaller orders to be held back by watermarks, and only larger orders to suffer primarily from fragmentation. This better matches the checks in reclaim's shrink_zones(). There are two other smaller functional changes. One is that the upgrade from async migration to light sync migration will always occur after the initial compaction. This is how it has been until recent patch "mm, oom: protect !costly allocations some more", which introduced upgrading the mode based on COMPACT_COMPLETE result, but kept the final compaction always upgraded, which made it even more special. It's better to return to the simpler handling for now, as migration modes will be further modified later in the series. The second change is that once both reclaim and compaction declare it's not worth to retry the reclaim/compact loop, there is no final compaction attempt. As argued above, this is intentional. If that final compaction were to succeed, it would be due to a wrong retry decision, or simply a race with somebody else freeing memory for us. The main outcome of this patch should be simpler code. Logically, the initial compaction without reclaim is the exceptional case to the reclaim/compaction scheme, but prior to the patch, it was the last loop iteration that was exceptional. Now the code matches the logic better. The change also enable the following patches. Link: http://lkml.kernel.org/r/20160721073614.24395-5-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |