04 May, 2017
1 commit
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kswapd is woken to reclaim a node based on a failed allocation request
from any eligible zone. Once reclaiming in balance_pgdat(), it will
continue reclaiming until there is an eligible zone available for the
zone it was woken for. kswapd tracks what zone it was recently woken
for in pgdat->kswapd_classzone_idx. If it has not been woken recently,
this zone will be 0.However, the decision on whether to sleep is made on
kswapd_classzone_idx which is 0 without a recent wakeup request and that
classzone does not account for lowmem reserves. This allows kswapd to
sleep when a low small zone such as ZONE_DMA is balanced for a GFP_DMA
request even if a stream of allocations cannot use that zone. While
kswapd may be woken again shortly in the near future there are two
consequences -- the pgdat bits that control congestion are cleared
prematurely and direct reclaim is more likely as kswapd slept
prematurely.This patch flips kswapd_classzone_idx to default to MAX_NR_ZONES (an
invalid index) when there has been no recent wakeups. If there are no
wakeups, it'll decide whether to sleep based on the highest possible
zone available (MAX_NR_ZONES - 1). It then becomes critical that the
"pgdat balanced" decisions during reclaim and when deciding to sleep are
the same. If there is a mismatch, kswapd can stay awake continually
trying to balance tiny zones.simoop was used to evaluate it again. Two of the preparation patches
regressed the workload so they are included as the second set of
results. Otherwise this patch looks artifically excellent4.11.0-rc1 4.11.0-rc1 4.11.0-rc1
vanilla clear-v2 keepawake-v2
Amean p50-Read 21670074.18 ( 0.00%) 19786774.76 ( 8.69%) 22668332.52 ( -4.61%)
Amean p95-Read 25456267.64 ( 0.00%) 24101956.27 ( 5.32%) 26738688.00 ( -5.04%)
Amean p99-Read 29369064.73 ( 0.00%) 27691872.71 ( 5.71%) 30991404.52 ( -5.52%)
Amean p50-Write 1390.30 ( 0.00%) 1011.91 ( 27.22%) 924.91 ( 33.47%)
Amean p95-Write 412901.57 ( 0.00%) 34874.98 ( 91.55%) 1362.62 ( 99.67%)
Amean p99-Write 6668722.09 ( 0.00%) 575449.60 ( 91.37%) 16854.04 ( 99.75%)
Amean p50-Allocation 78714.31 ( 0.00%) 84246.26 ( -7.03%) 74729.74 ( 5.06%)
Amean p95-Allocation 175533.51 ( 0.00%) 400058.43 (-127.91%) 101609.74 ( 42.11%)
Amean p99-Allocation 247003.02 ( 0.00%) 10905600.00 (-4315.17%) 125765.57 ( 49.08%)With this patch on top, write and allocation latencies are massively
improved. The read latencies are slightly impaired but it's worth
noting that this is mostly due to the IO scheduler and not directly
related to reclaim. The vmstats are a bit of a mix but the relevant
ones are as follows;4.10.0-rc7 4.10.0-rc7 4.10.0-rc7
mmots-20170209 clear-v1r25keepawake-v1r25
Swap Ins 0 0 0
Swap Outs 0 608 0
Direct pages scanned 6910672 3132699 6357298
Kswapd pages scanned 57036946 82488665 56986286
Kswapd pages reclaimed 55993488 63474329 55939113
Direct pages reclaimed 6905990 2964843 6352115
Kswapd efficiency 98% 76% 98%
Kswapd velocity 12494.375 17597.507 12488.065
Direct efficiency 99% 94% 99%
Direct velocity 1513.835 668.306 1393.148
Page writes by reclaim 0.000 4410243.000 0.000
Page writes file 0 4409635 0
Page writes anon 0 608 0
Page reclaim immediate 1036792 14175203 10425714.11.0-rc1 4.11.0-rc1 4.11.0-rc1
vanilla clear-v2 keepawake-v2
Swap Ins 0 12 0
Swap Outs 0 838 0
Direct pages scanned 6579706 3237270 6256811
Kswapd pages scanned 61853702 79961486 54837791
Kswapd pages reclaimed 60768764 60755788 53849586
Direct pages reclaimed 6579055 2987453 6256151
Kswapd efficiency 98% 75% 98%
Page writes by reclaim 0.000 4389496.000 0.000
Page writes file 0 4388658 0
Page writes anon 0 838 0
Page reclaim immediate 1073573 14473009 982507Swap-outs are equivalent to baseline.
Direct reclaim is reduced but not eliminated. It's worth noting that
there are two periods of direct reclaim for this workload. The first is
when it switches from preparing the files for the actual test itself.
It's a lot of file IO followed by a lot of allocs that reclaims heavily
for a brief window. While direct reclaim is lower with clear-v2, it is
due to kswapd scanning aggressively and trying to reclaim the world
which is not the right thing to do. With the patches applied, there is
still direct reclaim but the phase change from "creating work files" to
starting multiple threads that allocate a lot of anonymous memory faster
than kswapd can reclaim.Scanning/reclaim efficiency is restored by this patch.
Page writes from reclaim context are back at 0 which is ideal.
Pages immediately reclaimed after IO completes is slightly improved but
it is expected this will vary slightly.On UMA, there is almost no change so this is not expected to be a
universal win.[mgorman@suse.de: fix ->kswapd_classzone_idx initialization]
Link: http://lkml.kernel.org/r/20170406174538.5msrznj6nt6qpbx5@suse.de
Link: http://lkml.kernel.org/r/20170309075657.25121-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Acked-by: Vlastimil Babka
Acked-by: Michal Hocko
Cc: Hillf Danton
Cc: Johannes Weiner
Cc: Shantanu Goel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Mar, 2017
1 commit
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Commit bfc8c90139eb ("mem-hotplug: implement get/put_online_mems")
introduced new functions get/put_online_mems() and mem_hotplug_begin/end()
in order to allow similar semantics for memory hotplug like for cpu
hotplug.The corresponding functions for cpu hotplug are get/put_online_cpus()
and cpu_hotplug_begin/done() for cpu hotplug.The commit however missed to introduce functions that would serialize
memory hotplug operations like they are done for cpu hotplug with
cpu_maps_update_begin/done().This basically leaves mem_hotplug.active_writer unprotected and allows
concurrent writers to modify it, which may lead to problems as outlined
by commit f931ab479dd2 ("mm: fix devm_memremap_pages crash, use
mem_hotplug_{begin, done}").That commit was extended again with commit b5d24fda9c3d ("mm,
devm_memremap_pages: hold device_hotplug lock over mem_hotplug_{begin,
done}") which serializes memory hotplug operations for some call sites
by using the device_hotplug lock.In addition with commit 3fc21924100b ("mm: validate device_hotplug is held
for memory hotplug") a sanity check was added to mem_hotplug_begin() to
verify that the device_hotplug lock is held.This in turn triggers the following warning on s390:
WARNING: CPU: 6 PID: 1 at drivers/base/core.c:643 assert_held_device_hotplug+0x4a/0x58
Call Trace:
assert_held_device_hotplug+0x40/0x58)
mem_hotplug_begin+0x34/0xc8
add_memory_resource+0x7e/0x1f8
add_memory+0xda/0x130
add_memory_merged+0x15c/0x178
sclp_detect_standby_memory+0x2ae/0x2f8
do_one_initcall+0xa2/0x150
kernel_init_freeable+0x228/0x2d8
kernel_init+0x2a/0x140
kernel_thread_starter+0x6/0xcOne possible fix would be to add more lock_device_hotplug() and
unlock_device_hotplug() calls around each call site of
mem_hotplug_begin/end(). But that would give the device_hotplug lock
additional semantics it better should not have (serialize memory hotplug
operations).Instead add a new memory_add_remove_lock which has the similar semantics
like cpu_add_remove_lock for cpu hotplug.To keep things hopefully a bit easier the lock will be locked and unlocked
within the mem_hotplug_begin/end() functions.Link: http://lkml.kernel.org/r/20170314125226.16779-2-heiko.carstens@de.ibm.com
Signed-off-by: Heiko Carstens
Reported-by: Sebastian Ott
Acked-by: Dan Williams
Acked-by: Rafael J. Wysocki
Cc: Michal Hocko
Cc: Vladimir Davydov
Cc: Ben Hutchings
Cc: Gerald Schaefer
Cc: Martin Schwidefsky
Cc: Greg Kroah-Hartman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Mar, 2017
1 commit
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…hed.h> into <linux/sched/signal.h>
Fix up affected files that include this signal functionality via sched.h.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
25 Feb, 2017
5 commits
-
Commit 31bc3858ea3e ("add automatic onlining policy for the newly added
memory") provides the capability to have added memory automatically
onlined during add, but this appears to be slightly broken.The current implementation uses walk_memory_range() to call
online_memory_block, which uses memory_block_change_state() to online
the memory. Instead, we should be calling device_online() for the
memory block in online_memory_block(). This would online the memory
(the memory bus online routine memory_subsys_online() called from
device_online calls memory_block_change_state()) and properly update the
device struct offline flag.As a result of the current implementation, attempting to remove a memory
block after adding it using auto online fails. This is because doing a
remove, for instanceecho offline > /sys/devices/system/memory/memoryXXX/state
uses device_offline() which checks the dev->offline flag.
Link: http://lkml.kernel.org/r/20170222220744.8119.19687.stgit@ltcalpine2-lp14.aus.stglabs.ibm.com
Signed-off-by: Nathan Fontenot
Cc: Michael Ellerman
Cc: Michael Roth
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When mainline introduced commit a96dfddbcc04 ("base/memory, hotplug: fix
a kernel oops in show_valid_zones()"), it obtained the valid start and
end pfn from the given pfn range. The valid start pfn can fix the
actual issue, but it introduced another issue. The valid end pfn will
may exceed the given end_pfn.Although the incorrect overflow will not result in actual problem at
present, but I think it need to be fixed.[toshi.kani@hpe.com: remove assumption that end_pfn is aligned by MAX_ORDER_NR_PAGES]
Fixes: a96dfddbcc04 ("base/memory, hotplug: fix a kernel oops in show_valid_zones()")
Link: http://lkml.kernel.org/r/1486467299-22648-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang
Signed-off-by: Toshi Kani
Cc: Vlastimil Babka
Cc: Mel Gorman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We had considered all of the non-lru pages as unmovable before commit
bda807d44454 ("mm: migrate: support non-lru movable page migration").
But now some of non-lru pages like zsmalloc, virtio-balloon pages also
become movable. So we can offline such blocks by using non-lru page
migration.This patch straightforwardly adds non-lru migration code, which means
adding non-lru related code to the functions which scan over pfn and
collect pages to be migrated and isolate them before migration.Signed-off-by: Yisheng Xie
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Naoya Horiguchi
Cc: Vlastimil Babka
Cc: Andi Kleen
Cc: Hanjun Guo
Cc: Johannes Weiner
Cc: Joonsoo Kim
Cc: Mel Gorman
Cc: Reza Arbab
Cc: Taku Izumi
Cc: Vitaly Kuznetsov
Cc: Xishi Qiu
Cc: Yisheng Xie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It has no modular callers.
Cc: Dan Williams
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
mem_hotplug_begin() assumes that it can set mem_hotplug.active_writer
and run the hotplug process without racing another thread. Validate
this assumption with a lockdep assertion.Link: http://lkml.kernel.org/r/148693886229.16345.1770484669403334689.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams
Reported-by: Ben Hutchings
Cc: Michal Hocko
Cc: Toshi Kani
Cc: Vlastimil Babka
Cc: Logan Gunthorpe
Cc: Greg Kroah-Hartman
Cc: Masayoshi Mizuma
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Feb, 2017
1 commit
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To identify that pages of page table are allocated from bootmem
allocator, magic number sets to page->lru.next.But page->lru list is initialized in reserve_bootmem_region(). So when
calling free_pagetable(), the function cannot find the magic number of
pages. And free_pagetable() frees the pages by free_reserved_page() not
put_page_bootmem().But if the pages are allocated from bootmem allocator and used as page
table, the pages have private flag. So before freeing the pages, we
should clear the private flag by put_page_bootmem().Before applying the commit 7bfec6f47bb0 ("mm, page_alloc: check multiple
page fields with a single branch"), we could find the following visible
issue:BUG: Bad page state in process kworker/u1024:1
page:ffffea103cfd8040 count:0 mapcount:0 mappi
flags: 0x6fffff80000800(private)
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
bad because of flags: 0x800(private)
Call Trace:
[...] dump_stack+0x63/0x87
[...] bad_page+0x114/0x130
[...] free_pages_prepare+0x299/0x2d0
[...] free_hot_cold_page+0x31/0x150
[...] __free_pages+0x25/0x30
[...] free_pagetable+0x6f/0xb4
[...] remove_pagetable+0x379/0x7ff
[...] vmemmap_free+0x10/0x20
[...] sparse_remove_one_section+0x149/0x180
[...] __remove_pages+0x2e9/0x4f0
[...] arch_remove_memory+0x63/0xc0
[...] remove_memory+0x8c/0xc0
[...] acpi_memory_device_remove+0x79/0xa5
[...] acpi_bus_trim+0x5a/0x8d
[...] acpi_bus_trim+0x38/0x8d
[...] acpi_device_hotplug+0x1b7/0x418
[...] acpi_hotplug_work_fn+0x1e/0x29
[...] process_one_work+0x152/0x400
[...] worker_thread+0x125/0x4b0
[...] kthread+0xd8/0xf0
[...] ret_from_fork+0x22/0x40And the issue still silently occurs.
Until freeing the pages of page table allocated from bootmem allocator,
the page->freelist is never used. So the patch sets magic number to
page->freelist instead of page->lru.next.[isimatu.yasuaki@jp.fujitsu.com: fix merge issue]
Link: http://lkml.kernel.org/r/722b1cc4-93ac-dd8b-2be2-7a7e313b3b0b@gmail.com
Link: http://lkml.kernel.org/r/2c29bd9f-5b67-02d0-18a3-8828e78bbb6f@gmail.com
Signed-off-by: Yasuaki Ishimatsu
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: H. Peter Anvin
Cc: Dave Hansen
Cc: Vlastimil Babka
Cc: Mel Gorman
Cc: Xishi Qiu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Feb, 2017
2 commits
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Reading a sysfs "memoryN/valid_zones" file leads to the following oops
when the first page of a range is not backed by struct page.
show_valid_zones() assumes that 'start_pfn' is always valid for
page_zone().BUG: unable to handle kernel paging request at ffffea017a000000
IP: show_valid_zones+0x6f/0x160This issue may happen on x86-64 systems with 64GiB or more memory since
their memory block size is bumped up to 2GiB. [1] An example of such
systems is desribed below. 0x3240000000 is only aligned by 1GiB and
this memory block starts from 0x3200000000, which is not backed by
struct page.BIOS-e820: [mem 0x0000003240000000-0x000000603fffffff] usable
Since test_pages_in_a_zone() already checks holes, fix this issue by
extending this function to return 'valid_start' and 'valid_end' for a
given range. show_valid_zones() then proceeds with the valid range.[1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on
large-memory x86-64 systems")'Link: http://lkml.kernel.org/r/20170127222149.30893-3-toshi.kani@hpe.com
Signed-off-by: Toshi Kani
Cc: Greg Kroah-Hartman
Cc: Zhang Zhen
Cc: Reza Arbab
Cc: David Rientjes
Cc: Dan Williams
Cc: [4.4+]Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "fix a kernel oops when reading sysfs valid_zones", v2.
A sysfs memory file is created for each 2GiB memory block on x86-64 when
the system has 64GiB or more memory. [1] When the start address of a
memory block is not backed by struct page, i.e. a memory range is not
aligned by 2GiB, reading its 'valid_zones' attribute file leads to a
kernel oops. This issue was observed on multiple x86-64 systems with
more than 64GiB of memory. This patch-set fixes this issue.Patch 1 first fixes an issue in test_pages_in_a_zone(), which does not
test the start section.Patch 2 then fixes the kernel oops by extending test_pages_in_a_zone()
to return valid [start, end).Note for stable kernels: The memory block size change was made by commit
bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64
systems"), which was accepted to 3.9. However, this patch-set depends
on (and fixes) the change to test_pages_in_a_zone() made by commit
5f0f2887f4de ("mm/memory_hotplug.c: check for missing sections in
test_pages_in_a_zone()"), which was accepted to 4.4.So, I recommend that we backport it up to 4.4.
[1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on
large-memory x86-64 systems")'This patch (of 2):
test_pages_in_a_zone() does not check 'start_pfn' when it is aligned by
section since 'sec_end_pfn' is set equal to 'pfn'. Since this function
is called for testing the range of a sysfs memory file, 'start_pfn' is
always aligned by section.Fix it by properly setting 'sec_end_pfn' to the next section pfn.
Also make sure that this function returns 1 only when the range belongs
to a zone.Link: http://lkml.kernel.org/r/20170127222149.30893-2-toshi.kani@hpe.com
Signed-off-by: Toshi Kani
Cc: Andrew Banman
Cc: Reza Arbab
Cc: Greg KH
Cc: [4.4+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Jan, 2017
1 commit
-
online_{kernel|movable} is used to change the memory zone to
ZONE_{NORMAL|MOVABLE} and online the memory.To check that memory zone can be changed, zone_can_shift() is used.
Currently the function returns minus integer value, plus integer
value and 0. When the function returns minus or plus integer value,
it means that the memory zone can be changed to ZONE_{NORNAL|MOVABLE}.But when the function returns 0, there are two meanings.
One of the meanings is that the memory zone does not need to be changed.
For example, when memory is in ZONE_NORMAL and onlined by online_kernel
the memory zone does not need to be changed.Another meaning is that the memory zone cannot be changed. When memory
is in ZONE_NORMAL and onlined by online_movable, the memory zone may
not be changed to ZONE_MOVALBE due to memory online limitation(see
Documentation/memory-hotplug.txt). In this case, memory must not be
onlined.The patch changes the return type of zone_can_shift() so that memory
online operation fails when memory zone cannot be changed as follows:Before applying patch:
# grep -A 35 "Node 2" /proc/zoneinfo
Node 2, zone Normal
node_scanned 0
spanned 8388608
present 7864320
managed 7864320
# echo online_movable > memory4097/state
# grep -A 35 "Node 2" /proc/zoneinfo
Node 2, zone Normal
node_scanned 0
spanned 8388608
present 8388608
managed 8388608online_movable operation succeeded. But memory is onlined as
ZONE_NORMAL, not ZONE_MOVABLE.After applying patch:
# grep -A 35 "Node 2" /proc/zoneinfo
Node 2, zone Normal
node_scanned 0
spanned 8388608
present 7864320
managed 7864320
# echo online_movable > memory4097/state
bash: echo: write error: Invalid argument
# grep -A 35 "Node 2" /proc/zoneinfo
Node 2, zone Normal
node_scanned 0
spanned 8388608
present 7864320
managed 7864320online_movable operation failed because of failure of changing
the memory zone from ZONE_NORMAL to ZONE_MOVABLEFixes: df429ac03936 ("memory-hotplug: more general validation of zone during online")
Link: http://lkml.kernel.org/r/2f9c3837-33d7-b6e5-59c0-6ca4372b2d84@gmail.com
Signed-off-by: Yasuaki Ishimatsu
Reviewed-by: Reza Arbab
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Dec, 2016
1 commit
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In commit c5320926e370 ("mem-hotplug: introduce movable_node boot
option"), the memblock allocation direction is changed to bottom-up and
then back to top-down like this:1. memblock_set_bottom_up(true), called by cmdline_parse_movable_node().
2. memblock_set_bottom_up(false), called by x86's numa_init().Even though (1) occurs in generic mm code, it is wrapped by #ifdef
CONFIG_MOVABLE_NODE, which depends on X86_64.This means that when we extend CONFIG_MOVABLE_NODE to non-x86 arches,
things will be unbalanced. (1) will happen for them, but (2) will not.This toggle was added in the first place because x86 has a delay between
adding memblocks and marking them as hotpluggable. Since other arches
do this marking either immediately or not at all, they do not require
the bottom-up toggle.So, resolve things by moving (1) from cmdline_parse_movable_node() to
x86's setup_arch(), immediately after the movable_node parameter has
been parsed.Link: http://lkml.kernel.org/r/1479160961-25840-3-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab
Acked-by: Balbir Singh
Cc: "Aneesh Kumar K.V"
Cc: "H. Peter Anvin"
Cc: Alistair Popple
Cc: Aneesh Kumar K.V
Cc: Benjamin Herrenschmidt
Cc: Bharata B Rao
Cc: Frank Rowand
Cc: Ingo Molnar
Cc: Michael Ellerman
Cc: Nathan Fontenot
Cc: Paul Mackerras
Cc: Rob Herring
Cc: Stewart Smith
Cc: Thomas Gleixner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Oct, 2016
2 commits
-
When I removed the per-zone bitlock hashed waitqueues in commit
9dcb8b685fc3 ("mm: remove per-zone hashtable of bitlock waitqueues"), I
removed all the magic hotplug memory initialization of said waitqueues
too.But when I actually _tested_ the resulting build, I stupidly assumed
that "allmodconfig" would enable memory hotplug. And it doesn't,
because it enables KASAN instead, which then disables hotplug memory
support.As a result, my build test of the per-zone waitqueues was totally
broken, and I didn't notice that the compiler warns about the now unused
iterator variable 'i'.I guess I should be happy that that seems to be the worst breakage from
my clearly horribly failed test coverage.Reported-by: Stephen Rothwell
Signed-off-by: Linus Torvalds -
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
Tested-by: Bob Peterson
Acked-by: Mel Gorman
Cc: Peter Zijlstra
Cc: Andy Lutomirski
Cc: Steven Whitehouse
Signed-off-by: Linus Torvalds
08 Oct, 2016
1 commit
-
In dissolve_free_huge_pages(), free hugepages will be dissolved without
making sure that there are enough of them left to satisfy hugepage
reservations.Fix this by adding a return value to dissolve_free_huge_pages() and
checking h->free_huge_pages vs. h->resv_huge_pages. Note that this may
lead to the situation where dissolve_free_huge_page() returns an error
and all free hugepages that were dissolved before that error are lost,
while the memory block still cannot be set offline.Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Link: http://lkml.kernel.org/r/20160926172811.94033-3-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer
Acked-by: Michal Hocko
Acked-by: Naoya Horiguchi
Cc: "Kirill A . Shutemov"
Cc: Vlastimil Babka
Cc: Mike Kravetz
Cc: "Aneesh Kumar K . V"
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Rui Teng
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Sep, 2016
1 commit
-
9bb627be47a5 ("mem-hotplug: don't clear the only node in new_node_page()")
prevents allocating from an empty nodemask, but as David points out, it is
still wrong. As node_online_map may include memoryless nodes, only
allocating from these nodes is meaningless.This patch uses node_states[N_MEMORY] mask to prevent the above case.
Fixes: 9bb627be47a5 ("mem-hotplug: don't clear the only node in new_node_page()")
Fixes: 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline")
Link: http://lkml.kernel.org/r/1474447117.28370.6.camel@TP420
Signed-off-by: Li Zhong
Suggested-by: David Rientjes
Acked-by: Vlastimil Babka
Cc: Michal Hocko
Cc: John Allen
Cc: Xishi Qiu
Cc: Joonsoo Kim
Cc: Naoya Horiguchi
Cc: Tetsuo Handa
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Sep, 2016
1 commit
-
Commit 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest
neighbor node when mem-offline") introduced new_node_page() for memory
hotplug.In new_node_page(), the nid is cleared before calling
__alloc_pages_nodemask(). But if it is the only node of the system, and
the first round allocation fails, it will not be able to get memory from
an empty nodemask, and will trigger oom.The patch checks whether it is the last node on the system, and if it
is, then don't clear the nid in the nodemask.Fixes: 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline")
Link: http://lkml.kernel.org/r/1473044391.4250.19.camel@TP420
Signed-off-by: Li Zhong
Reported-by: John Allen
Acked-by: Vlastimil Babka
Cc: Xishi Qiu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Aug, 2016
1 commit
-
The following oops occurs after a pgdat is hotadded:
Unable to handle kernel paging request for data at address 0x00c30001
Faulting instruction address: 0xc00000000022f8f4
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter nls_utf8 isofs sg virtio_balloon uio_pdrv_genirq uio ip_tables xfs libcrc32c sr_mod cdrom sd_mod virtio_net ibmvscsi scsi_transport_srp virtio_pci virtio_ring virtio dm_mirror dm_region_hash dm_log dm_mod
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.8.0-rc1-device #110
task: c000000000ef3080 task.stack: c000000000f6c000
NIP: c00000000022f8f4 LR: c00000000022f948 CTR: 0000000000000000
REGS: c000000000f6fa50 TRAP: 0300 Tainted: G W (4.8.0-rc1-device)
MSR: 800000010280b033 CR: 84002028 XER: 20000000
CFAR: d000000001d2013c DAR: 0000000000c30001 DSISR: 40000000 SOFTE: 0
NIP refresh_cpu_vm_stats+0x1a4/0x2f0
LR refresh_cpu_vm_stats+0x1f8/0x2f0
Call Trace:
refresh_cpu_vm_stats+0x1f8/0x2f0 (unreliable)Add per_cpu_nodestats initialization to the hotplug codepath.
Link: http://lkml.kernel.org/r/1470931473-7090-1-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab
Cc: Mel Gorman
Cc: Paul Mackerras
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Jul, 2016
3 commits
-
If we offline a node, alloc the new page from a nearest neighbor node
instead of the current node or other remote nodes, because re-migrate is
a waste of time and the distance of the remote nodes is often very
large.Also use GFP_HIGHUSER_MOVABLE to alloc new page if the zone is movable
zone or highmem zone.Link: http://lkml.kernel.org/r/5795E18B.5060302@huawei.com
Signed-off-by: Xishi Qiu
Cc: Joonsoo Kim
Cc: Vlastimil Babka
Cc: Naoya Horiguchi
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
kswapd goes through some complex steps trying to figure out if it should
stay awake based on the classzone_idx and the requested order. It is
unnecessarily complex and passes in an invalid classzone_idx to
balance_pgdat(). What matters most of all is whether a larger order has
been requsted and whether kswapd successfully reclaimed at the previous
order. This patch irons out the logic to check just that and the end
result is less headache inducing.Link: http://lkml.kernel.org/r/1467970510-21195-10-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Acked-by: Johannes Weiner
Acked-by: Vlastimil Babka
Cc: Hillf Danton
Cc: Joonsoo Kim
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the LRU lists from the zone to the node and related data such
as counters, tracing, congestion tracking and writeback tracking.Unfortunately, due to reclaim and compaction retry logic, it is
necessary to account for the number of LRU pages on both zone and node
logic. Most reclaim logic is based on the node counters but the retry
logic uses the zone counters which do not distinguish inactive and
active sizes. It would be possible to leave the LRU counters on a
per-zone basis but it's a heavier calculation across multiple cache
lines that is much more frequent than the retry checks.Other than the LRU counters, this is mostly a mechanical patch but note
that it introduces a number of anomalies. For example, the scans are
per-zone but using per-node counters. We also mark a node as congested
when a zone is congested. This causes weird problems that are fixed
later but is easier to review.In the event that there is excessive overhead on 32-bit systems due to
the nodes being on LRU then there are two potential solutions1. Long-term isolation of highmem pages when reclaim is lowmem
When pages are skipped, they are immediately added back onto the LRU
list. If lowmem reclaim persisted for long periods of time, the same
highmem pages get continually scanned. The idea would be that lowmem
keeps those pages on a separate list until a reclaim for highmem pages
arrives that splices the highmem pages back onto the LRU. It potentially
could be implemented similar to the UNEVICTABLE list.That would reduce the skip rate with the potential corner case is that
highmem pages have to be scanned and reclaimed to free lowmem slab pages.2. Linear scan lowmem pages if the initial LRU shrink fails
This will break LRU ordering but may be preferable and faster during
memory pressure than skipping LRU pages.Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Acked-by: Johannes Weiner
Acked-by: Vlastimil Babka
Cc: Hillf Danton
Cc: Joonsoo Kim
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jul, 2016
2 commits
-
When memory is onlined, we are only able to rezone from ZONE_MOVABLE to
ZONE_KERNEL, or from (ZONE_MOVABLE - 1) to ZONE_MOVABLE.To be more flexible, use the following criteria instead; to online
memory from zone X into zone Y,* Any zones between X and Y must be unused.
* If X is lower than Y, the onlined memory must lie at the end of X.
* If X is higher than Y, the onlined memory must lie at the start of X.Add zone_can_shift() to make this determination.
Link: http://lkml.kernel.org/r/1462816419-4479-3-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab
Reviewd-by: Yasuaki Ishimatsu
Cc: Greg Kroah-Hartman
Cc: Daniel Kiper
Cc: Dan Williams
Cc: Vlastimil Babka
Cc: Tang Chen
Cc: Joonsoo Kim
Cc: David Vrabel
Cc: Vitaly Kuznetsov
Cc: David Rientjes
Cc: Andrew Banman
Cc: Chen Yucong
Cc: Yasunori Goto
Cc: Zhang Zhen
Cc: Shaohua Li
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add move_pfn_range(), a wrapper to call move_pfn_range_left() or
move_pfn_range_right().No functional change. This will be utilized by a later patch.
Link: http://lkml.kernel.org/r/1462816419-4479-2-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab
Reviewed-by: Yasuaki Ishimatsu
Cc: Greg Kroah-Hartman
Cc: Daniel Kiper
Cc: Dan Williams
Cc: Vlastimil Babka
Cc: Tang Chen
Cc: Joonsoo Kim
Cc: David Vrabel
Cc: Vitaly Kuznetsov
Cc: David Rientjes
Cc: Andrew Banman
Cc: Chen Yucong
Cc: Yasunori Goto
Cc: Zhang Zhen
Cc: Shaohua Li
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 May, 2016
2 commits
-
The register_page_bootmem_info_node() function needs to be marked __init
in order to avoid a new warning introduced by commit f65e91df25aa ("mm:
use early_pfn_to_nid in register_page_bootmem_info_node").Otherwise you'll get a warning about how a non-init function calls
early_pfn_to_nid (which is __meminit)Cc: Yang Shi
Cc: Andrew Morton
Signed-off-by: Linus Torvalds -
register_page_bootmem_info_node() is invoked in mem_init(), so it will
be called before page_alloc_init_late() if DEFERRED_STRUCT_PAGE_INIT is
enabled. But, pfn_to_nid() depends on memmap which won't be fully setup
until page_alloc_init_late() is done, so replace pfn_to_nid() by
early_pfn_to_nid().Link: http://lkml.kernel.org/r/1464210007-30930-1-git-send-email-yang.shi@linaro.org
Signed-off-by: Yang Shi
Cc: Mel Gorman
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 May, 2016
3 commits
-
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE specifies the default value for the
memory hotplug onlining policy. Add a command line parameter to make it
possible to override the default. It may come handy for debug and
testing purposes.Signed-off-by: Vitaly Kuznetsov
Cc: Jonathan Corbet
Cc: Dan Williams
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Cc: David Vrabel
Cc: David Rientjes
Cc: Igor Mammedov
Cc: Lennart Poettering
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patchset continues the work I started with commit 31bc3858ea3e
("memory-hotplug: add automatic onlining policy for the newly added
memory").Initially I was going to stop there and bring the policy setting logic
to userspace. I met two issues on this way:1) It is possible to have memory hotplugged at boot (e.g. with QEMU).
These blocks stay offlined if we turn the onlining policy on by
userspace.2) My attempt to bring this policy setting to systemd failed, systemd
maintainers suggest to change the default in kernel or ... to use
tmpfiles.d to alter the policy (which looks like a hack to me):
https://github.com/systemd/systemd/pull/2938Here I suggest to add a config option to set the default value for the
policy and a kernel command line parameter to make the override.This patch (of 2):
Introduce config option to set the default value for memory hotplug
onlining policy (/sys/devices/system/memory/auto_online_blocks). The
reason one would want to turn this option on are to have early onlining
for hotpluggable memory available at boot and to not require any
userspace actions to make memory hotplug work.[akpm@linux-foundation.org: tweak Kconfig text]
Signed-off-by: Vitaly Kuznetsov
Cc: Jonathan Corbet
Cc: Dan Williams
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Cc: David Vrabel
Cc: David Rientjes
Cc: Igor Mammedov
Cc: Lennart Poettering
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Make is_mem_section_removable() return bool to improve readability due
to this particular function only using either one or zero as its return
value.Signed-off-by: Yaowei Bai
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Mar, 2016
5 commits
-
Kernel style prefers a single string over split strings when the string is
'user-visible'.Miscellanea:
- Add a missing newline
- Realign argumentsSigned-off-by: Joe Perches
Acked-by: Tejun Heo [percpu]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
online_pages() simply returns an error value if
memory_notify(MEM_GOING_ONLINE, &arg) return a value that is not what we
want for successfully onlining target pages. This patch arms to print
more failure information like offline_pages() in online_pages.This patch also converts printk(KERN_) to pr_(), and moves
__offline_pages() to not print failure information with KERN_INFO
according to David Rientjes's suggestion[1].[1] https://lkml.org/lkml/2016/2/24/1094
Signed-off-by: Chen Yucong
Acked-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The success of CMA allocation largely depends on the success of
migration and key factor of it is page reference count. Until now, page
reference is manipulated by direct calling atomic functions so we cannot
follow up who and where manipulate it. Then, it is hard to find actual
reason of CMA allocation failure. CMA allocation should be guaranteed
to succeed so finding offending place is really important.In this patch, call sites where page reference is manipulated are
converted to introduced wrapper function. This is preparation step to
add tracepoint to each page reference manipulation function. With this
facility, we can easily find reason of CMA allocation failure. There is
no functional change in this patch.In addition, this patch also converts reference read sites. It will
help a second step that renames page._count to something else and
prevents later attempt to direct access to it (Suggested by Andrew).Signed-off-by: Joonsoo Kim
Acked-by: Michal Nazarewicz
Acked-by: Vlastimil Babka
Cc: Minchan Kim
Cc: Mel Gorman
Cc: "Kirill A. Shutemov"
Cc: Sergey Senozhatsky
Cc: Steven Rostedt
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We can reuse the nid we've determined instead of repeated pfn_to_nid()
usages. Also zone_to_nid() should be a bit cheaper in general than
pfn_to_nid().Signed-off-by: Vlastimil Babka
Cc: Andrea Arcangeli
Cc: "Kirill A. Shutemov"
Cc: Rik van Riel
Cc: Joonsoo Kim
Cc: Mel Gorman
Cc: David Rientjes
Cc: Michal Hocko
Cc: Johannes Weiner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Memory compaction can be currently performed in several contexts:
- kswapd balancing a zone after a high-order allocation failure
- direct compaction to satisfy a high-order allocation, including THP
page fault attemps
- khugepaged trying to collapse a hugepage
- manually from /procThe purpose of compaction is two-fold. The obvious purpose is to
satisfy a (pending or future) high-order allocation, and is easy to
evaluate. The other purpose is to keep overal memory fragmentation low
and help the anti-fragmentation mechanism. The success wrt the latter
purpose is moreThe current situation wrt the purposes has a few drawbacks:
- compaction is invoked only when a high-order page or hugepage is not
available (or manually). This might be too late for the purposes of
keeping memory fragmentation low.
- direct compaction increases latency of allocations. Again, it would
be better if compaction was performed asynchronously to keep
fragmentation low, before the allocation itself comes.
- (a special case of the previous) the cost of compaction during THP
page faults can easily offset the benefits of THP.
- kswapd compaction appears to be complex, fragile and not working in
some scenarios. It could also end up compacting for a high-order
allocation request when it should be reclaiming memory for a later
order-0 request.To improve the situation, we should be able to benefit from an
equivalent of kswapd, but for compaction - i.e. a background thread
which responds to fragmentation and the need for high-order allocations
(including hugepages) somewhat proactively.One possibility is to extend the responsibilities of kswapd, which could
however complicate its design too much. It should be better to let
kswapd handle reclaim, as order-0 allocations are often more critical
than high-order ones.Another possibility is to extend khugepaged, but this kthread is a
single instance and tied to THP configs.This patch goes with the option of a new set of per-node kthreads called
kcompactd, and lays the foundations, without introducing any new
tunables. The lifecycle mimics kswapd kthreads, including the memory
hotplug hooks.For compaction, kcompactd uses the standard compaction_suitable() and
ompact_finished() criteria and the deferred compaction functionality.
Unlike direct compaction, it uses only sync compaction, as there's no
allocation latency to minimize.This patch doesn't yet add a call to wakeup_kcompactd. The kswapd
compact/reclaim loop for high-order pages will be replaced by waking up
kcompactd in the next patch with the description of what's wrong with
the old approach.Waking up of the kcompactd threads is also tied to kswapd activity and
follows these rules:
- we don't want to affect any fastpaths, so wake up kcompactd only from
the slowpath, as it's done for kswapd
- if kswapd is doing reclaim, it's more important than compaction, so
don't invoke kcompactd until kswapd goes to sleep
- the target order used for kswapd is passed to kcompactdFuture possible future uses for kcompactd include the ability to wake up
kcompactd on demand in special situations, such as when hugepages are
not available (currently not done due to __GFP_NO_KSWAPD) or when a
fragmentation event (i.e. __rmqueue_fallback()) occurs. It's also
possible to perform periodic compaction with kcompactd.[arnd@arndb.de: fix build errors with kcompactd]
[paul.gortmaker@windriver.com: don't use modular references for non modular code]
Signed-off-by: Vlastimil Babka
Cc: Andrea Arcangeli
Cc: "Kirill A. Shutemov"
Cc: Rik van Riel
Cc: Joonsoo Kim
Cc: Mel Gorman
Cc: David Rientjes
Cc: Michal Hocko
Cc: Johannes Weiner
Signed-off-by: Arnd Bergmann
Signed-off-by: Paul Gortmaker
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Mar, 2016
2 commits
-
There is a performance drop report due to hugepage allocation and in
there half of cpu time are spent on pageblock_pfn_to_page() in
compaction [1].In that workload, compaction is triggered to make hugepage but most of
pageblocks are un-available for compaction due to pageblock type and
skip bit so compaction usually fails. Most costly operations in this
case is to find valid pageblock while scanning whole zone range. To
check if pageblock is valid to compact, valid pfn within pageblock is
required and we can obtain it by calling pageblock_pfn_to_page(). This
function checks whether pageblock is in a single zone and return valid
pfn if possible. Problem is that we need to check it every time before
scanning pageblock even if we re-visit it and this turns out to be very
expensive in this workload.Although we have no way to skip this pageblock check in the system where
hole exists at arbitrary position, we can use cached value for zone
continuity and just do pfn_to_page() in the system where hole doesn't
exist. This optimization considerably speeds up in above workload.Before vs After
Max: 1096 MB/s vs 1325 MB/s
Min: 635 MB/s 1015 MB/s
Avg: 899 MB/s 1194 MB/sAvg is improved by roughly 30% [2].
[1]: http://www.spinics.net/lists/linux-mm/msg97378.html
[2]: https://lkml.org/lkml/2015/12/9/23[akpm@linux-foundation.org: don't forget to restore zone->contiguous on error path, per Vlastimil]
Signed-off-by: Joonsoo Kim
Reported-by: Aaron Lu
Acked-by: Vlastimil Babka
Tested-by: Aaron Lu
Cc: Mel Gorman
Cc: Rik van Riel
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently, all newly added memory blocks remain in 'offline' state
unless someone onlines them, some linux distributions carry special udev
rules like:SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", ATTR{state}="online"
to make this happen automatically. This is not a great solution for
virtual machines where memory hotplug is being used to address high
memory pressure situations as such onlining is slow and a userspace
process doing this (udev) has a chance of being killed by the OOM killer
as it will probably require to allocate some memory.Introduce default policy for the newly added memory blocks in
/sys/devices/system/memory/auto_online_blocks file with two possible
values: "offline" which preserves the current behavior and "online"
which causes all newly added memory blocks to go online as soon as
they're added. The default is "offline".Signed-off-by: Vitaly Kuznetsov
Reviewed-by: Daniel Kiper
Cc: Jonathan Corbet
Cc: Greg Kroah-Hartman
Cc: Daniel Kiper
Cc: Dan Williams
Cc: Tang Chen
Cc: David Vrabel
Acked-by: David Rientjes
Cc: Naoya Horiguchi
Cc: Xishi Qiu
Cc: Mel Gorman
Cc: "K. Y. Srinivasan"
Cc: Igor Mammedov
Cc: Kay Sievers
Cc: Konrad Rzeszutek Wilk
Cc: Boris Ostrovsky
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Jan, 2016
1 commit
-
Set IORESOURCE_SYSTEM_RAM in struct resource.flags of "System
RAM" entries.Signed-off-by: Toshi Kani
Signed-off-by: Borislav Petkov
Acked-by: David Vrabel # xen
Cc: Andrew Banman
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Boris Ostrovsky
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Dan Williams
Cc: David Rientjes
Cc: Denys Vlasenko
Cc: Gu Zheng
Cc: H. Peter Anvin
Cc: Konrad Rzeszutek Wilk
Cc: Linus Torvalds
Cc: Luis R. Rodriguez
Cc: Mel Gorman
Cc: Naoya Horiguchi
Cc: Peter Zijlstra
Cc: Tang Chen
Cc: Thomas Gleixner
Cc: Toshi Kani
Cc: linux-arch@vger.kernel.org
Cc: linux-mm
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1453841853-11383-9-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar
16 Jan, 2016
1 commit
-
In support of providing struct page for large persistent memory
capacities, use struct vmem_altmap to change the default policy for
allocating memory for the memmap array. The default vmemmap_populate()
allocates page table storage area from the page allocator. Given
persistent memory capacities relative to DRAM it may not be feasible to
store the memmap in 'System Memory'. Instead vmem_altmap represents
pre-allocated "device pages" to satisfy vmemmap_alloc_block_buf()
requests.Signed-off-by: Dan Williams
Reported-by: kbuild test robot
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: "H. Peter Anvin"
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Jan, 2016
1 commit
-
Out of memory condition is not a bug and while we can't add new memory
in such case crashing the system seems wrong. Propagating the return
value from register_memory_resource() requires interface change.Signed-off-by: Vitaly Kuznetsov
Reviewed-by: Igor Mammedov
Acked-by: David Rientjes
Cc: Tang Chen
Cc: Naoya Horiguchi
Cc: Xishi Qiu
Cc: Sheng Yong
Cc: Zhu Guihua
Cc: Dan Williams
Cc: David Vrabel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Dec, 2015
1 commit
-
test_pages_in_a_zone() does not account for the possibility of missing
sections in the given pfn range. pfn_valid_within always returns 1 when
CONFIG_HOLES_IN_ZONE is not set, allowing invalid pfns from missing
sections to pass the test, leading to a kernel oops.Wrap an additional pfn loop with PAGES_PER_SECTION granularity to check
for missing sections before proceeding into the zone-check code.This also prevents a crash from offlining memory devices with missing
sections. Despite this, it may be a good idea to keep the related patch
'[PATCH 3/3] drivers: memory: prohibit offlining of memory blocks with
missing sections' because missing sections in a memory block may lead to
other problems not covered by the scope of this fix.Signed-off-by: Andrew Banman
Acked-by: Alex Thorlton
Cc: Russ Anderson
Cc: Alex Thorlton
Cc: Yinghai Lu
Cc: Greg KH
Cc: Seth Jennings
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
