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There is no reason to print warnings when balloon page allocation fails,
as they are expected and can be handled gracefully. Since VMware
balloon now uses balloon-compaction infrastructure, and suppressed these
warnings before, it is also beneficial to suppress these warnings to
keep the same behavior that the balloon had before.
Cc: Jason Wang <[email protected]>
Signed-off-by: Nadav Amit <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
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Lots of comments bitrotted. Fix them up.
Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
Reviewed-by: Wei Wang <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Ralph Campbell <[email protected]>
Acked-by: Nadav Amit <[email protected]>
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A #GP is reported in the guest when requesting balloon inflation via
virtio-balloon. The reason is that the virtio-balloon driver has
removed the page from its internal page list (via balloon_page_pop),
but balloon_page_enqueue_one also calls "list_del" to do the removal.
This is necessary when it's used from balloon_page_enqueue_list, but
not from balloon_page_enqueue.
Move list_del to balloon_page_enqueue, and update comments accordingly.
Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
Signed-off-by: Wei Wang <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
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We want the char/misc driver fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Introduce interfaces for ballooning enqueueing and dequeueing of a list
of pages. These interfaces reduce the overhead of storing and restoring
IRQs by batching the operations. In addition they do not panic if the
list of pages is empty.
Cc: Jason Wang <[email protected]>
Cc: [email protected]
Cc: [email protected]
Acked-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Xavier Deguillard <[email protected]>
Signed-off-by: Nadav Amit <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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fill_balloon doing memory allocations under balloon_lock
can cause a deadlock when leak_balloon is called from
virtballoon_oom_notify and tries to take same lock.
To fix, split page allocation and enqueue and do allocations outside the lock.
Here's a detailed analysis of the deadlock by Tetsuo Handa:
In leak_balloon(), mutex_lock(&vb->balloon_lock) is called in order to
serialize against fill_balloon(). But in fill_balloon(),
alloc_page(GFP_HIGHUSER[_MOVABLE] | __GFP_NOMEMALLOC | __GFP_NORETRY) is
called with vb->balloon_lock mutex held. Since GFP_HIGHUSER[_MOVABLE]
implies __GFP_DIRECT_RECLAIM | __GFP_IO | __GFP_FS, despite __GFP_NORETRY
is specified, this allocation attempt might indirectly depend on somebody
else's __GFP_DIRECT_RECLAIM memory allocation. And such indirect
__GFP_DIRECT_RECLAIM memory allocation might call leak_balloon() via
virtballoon_oom_notify() via blocking_notifier_call_chain() callback via
out_of_memory() when it reached __alloc_pages_may_oom() and held oom_lock
mutex. Since vb->balloon_lock mutex is already held by fill_balloon(), it
will cause OOM lockup.
Thread1 Thread2
fill_balloon()
takes a balloon_lock
balloon_page_enqueue()
alloc_page(GFP_HIGHUSER_MOVABLE)
direct reclaim (__GFP_FS context) takes a fs lock
waits for that fs lock alloc_page(GFP_NOFS)
__alloc_pages_may_oom()
takes the oom_lock
out_of_memory()
blocking_notifier_call_chain()
leak_balloon()
tries to take that balloon_lock and deadlocks
Reported-by: Tetsuo Handa <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Wei Wang <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
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Introduce a new migration mode that allow to offload the copy to a device
DMA engine. This changes the workflow of migration and not all
address_space migratepage callback can support this.
This is intended to be use by migrate_vma() which itself is use for thing
like HMM (see include/linux/hmm.h).
No additional per-filesystem migratepage testing is needed. I disables
MIGRATE_SYNC_NO_COPY in all problematic migratepage() callback and i
added comment in those to explain why (part of this patch). The commit
message is unclear it should say that any callback that wish to support
this new mode need to be aware of the difference in the migration flow
from other mode.
Some of these callbacks do extra locking while copying (aio, zsmalloc,
balloon, ...) and for DMA to be effective you want to copy multiple
pages in one DMA operations. But in the problematic case you can not
easily hold the extra lock accross multiple call to this callback.
Usual flow is:
For each page {
1 - lock page
2 - call migratepage() callback
3 - (extra locking in some migratepage() callback)
4 - migrate page state (freeze refcount, update page cache, buffer
head, ...)
5 - copy page
6 - (unlock any extra lock of migratepage() callback)
7 - return from migratepage() callback
8 - unlock page
}
The new mode MIGRATE_SYNC_NO_COPY:
1 - lock multiple pages
For each page {
2 - call migratepage() callback
3 - abort in all problematic migratepage() callback
4 - migrate page state (freeze refcount, update page cache, buffer
head, ...)
} // finished all calls to migratepage() callback
5 - DMA copy multiple pages
6 - unlock all the pages
To support MIGRATE_SYNC_NO_COPY in the problematic case we would need a
new callback migratepages() (for instance) that deals with multiple
pages in one transaction.
Because the problematic cases are not important for current usage I did
not wanted to complexify this patchset even more for no good reason.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jérôme Glisse <[email protected]>
Cc: Aneesh Kumar <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: David Nellans <[email protected]>
Cc: Evgeny Baskakov <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Mark Hairgrove <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Sherry Cheung <[email protected]>
Cc: Subhash Gutti <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Bob Liu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Revert commit bb01b64cfab7 ("mm/balloon_compaction.c: enqueue zero page
to balloon device")'
Zeroing ballon pages is rather time consuming, especially when a lot of
pages are in flight. E.g. 7GB worth of ballooned memory takes 2.8s with
__GFP_ZERO while it takes ~491ms without it.
The original commit argued that zeroing will help ksmd to merge these
pages on the host but this argument is assuming that the host actually
marks balloon pages for ksm which is not universally true. So we pay
performance penalty for something that even might not be used in the end
which is wrong. The host can zero out pages on its own when there is a
need.
[[email protected]: new changelog text]
Link: http://lkml.kernel.org/r/[email protected]
Fixes: bb01b64cfab7 ("mm/balloon_compaction.c: enqueue zero page to balloon device")
Signed-off-by: Wei Wang <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: zhenwei.pi <[email protected]>
Cc: David Hildenbrand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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presently pages in the balloon device have random value, and these pages
will be scanned by ksmd on the host. They usually cannot be merged.
Enqueue zero pages will resolve this problem.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: zhenwei.pi <[email protected]>
Cc: Gioh Kim <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Rafael Aquini <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Now, VM has a feature to migrate non-lru movable pages so balloon
doesn't need custom migration hooks in migrate.c and compaction.c.
Instead, this patch implements the page->mapping->a_ops->
{isolate|migrate|putback} functions.
With that, we could remove hooks for ballooning in general migration
functions and make balloon compaction simple.
[[email protected]: compaction.h requires that the includer first include node.h]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Gioh Kim <[email protected]>
Signed-off-by: Minchan Kim <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Rafael Aquini <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
drivers/rtc: broken link fix
drm/i915 Fix typos in i915_gem_fence.c
Docs: fix missing word in REPORTING-BUGS
lib+mm: fix few spelling mistakes
MAINTAINERS: add git URL for APM driver
treewide: Fix typo in printk
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All are in comments.
Signed-off-by: Bogdan Sikora <[email protected]>
Cc: <[email protected]>
Cc: Rafael Aquini <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Jan Kara <[email protected]>
[[email protected]: more fixup]
Acked-by: Rafael Aquini <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>
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In balloon_page_dequeue, pages_lock should cover the loop
(ie, list_for_each_entry_safe). Otherwise, the cursor page could
be isolated by compaction and then list_del by isolation could
poison the page->lru.{prev,next} so the loop finally could
access wrong address like this. This patch fixes the bug.
general protection fault: 0000 [#1] SMP
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 2 PID: 82 Comm: vballoon Not tainted 4.4.0-rc5-mm1-access_bit+ #1906
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff8800a7ff0000 ti: ffff8800a7fec000 task.ti: ffff8800a7fec000
RIP: 0010:[<ffffffff8115e754>] [<ffffffff8115e754>] balloon_page_dequeue+0x54/0x130
RSP: 0018:ffff8800a7fefdc0 EFLAGS: 00010246
RAX: ffff88013fff9a70 RBX: ffffea000056fe00 RCX: 0000000000002b7d
RDX: ffff88013fff9a70 RSI: ffffea000056fe00 RDI: ffff88013fff9a68
RBP: ffff8800a7fefde8 R08: ffffea000056fda0 R09: 0000000000000000
R10: ffff8800a7fefd90 R11: 0000000000000001 R12: dead0000000000e0
R13: ffffea000056fe20 R14: ffff880138809070 R15: ffff880138809060
FS: 0000000000000000(0000) GS:ffff88013fc40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f229c10e000 CR3: 00000000b8b53000 CR4: 00000000000006a0
Stack:
0000000000000100 ffff880138809088 ffff880138809000 ffff880138809060
0000000000000046 ffff8800a7fefe28 ffffffff812c86d3 ffff880138809020
ffff880138809000 fffffffffff91900 0000000000000100 ffff880138809060
Call Trace:
[<ffffffff812c86d3>] leak_balloon+0x93/0x1a0
[<ffffffff812c8bc7>] balloon+0x217/0x2a0
[<ffffffff8143739e>] ? __schedule+0x31e/0x8b0
[<ffffffff81078160>] ? abort_exclusive_wait+0xb0/0xb0
[<ffffffff812c89b0>] ? update_balloon_stats+0xf0/0xf0
[<ffffffff8105b6e9>] kthread+0xc9/0xe0
[<ffffffff8105b620>] ? kthread_park+0x60/0x60
[<ffffffff8143b4af>] ret_from_fork+0x3f/0x70
[<ffffffff8105b620>] ? kthread_park+0x60/0x60
Code: 8d 60 e0 0f 84 af 00 00 00 48 8b 43 20 a8 01 75 3b 48 89 d8 f0 0f ba 28 00 72 10 48 8b 03 f6 c4 08 75 2f 48 89 df e8 8c 83 f9 ff <49> 8b 44 24 20 4d 8d 6c 24 20 48 83 e8 20 4d 39 f5 74 7a 4c 89
RIP [<ffffffff8115e754>] balloon_page_dequeue+0x54/0x130
RSP <ffff8800a7fefdc0>
---[ end trace 43cf28060d708d5f ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Cc: <[email protected]>
Signed-off-by: Minchan Kim <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Rafael Aquini <[email protected]>
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Clean up page migration a little by moving the trylock of newpage from
move_to_new_page() into __unmap_and_move(), where the old page has been
locked. Adjust unmap_and_move_huge_page() and balloon_page_migrate()
accordingly.
But make one kind-of-functional change on the way: whereas trylock of
newpage used to BUG() if it failed, now simply return -EAGAIN if so.
Cutting out BUG()s is good, right? But, to be honest, this is really to
extend the usefulness of the custom put_new_page feature, allowing a pool
of new pages to be shared perhaps with racing uses.
Use an "else" instead of that "skip_unmap" label.
Signed-off-by: Hugh Dickins <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Acked-by: Rafael Aquini <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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If CONFIG_BALLOON_COMPACTION=n balloon_page_insert() does not link pages
with balloon and doesn't set PagePrivate flag, as a result
balloon_page_dequeue() cannot get any pages because it thinks that all
of them are isolated. Without balloon compaction nobody can isolate
ballooned pages. It's safe to remove this check.
Fixes: d6d86c0a7f8d ("mm/balloon_compaction: redesign ballooned pages management").
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Reported-by: Matt Mullins <[email protected]>
Cc: <[email protected]> [3.17]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Always mark pages with PageBalloon even if balloon compaction is disabled
and expose this mark in /proc/kpageflags as KPF_BALLOON.
Also this patch adds three counters into /proc/vmstat: "balloon_inflate",
"balloon_deflate" and "balloon_migrate". They accumulate balloon
activity. Current size of balloon is (balloon_inflate - balloon_deflate)
pages.
All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON.
It should be selected by ballooning driver which wants use this feature.
Currently virtio-balloon is the only user.
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Cc: Rafael Aquini <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Now ballooned pages are detected using PageBalloon(). Fake mapping is no
longer required. This patch links ballooned pages to balloon device using
field page->private instead of page->mapping. Also this patch embeds
balloon_dev_info directly into struct virtio_balloon.
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Cc: Rafael Aquini <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Sasha Levin reported KASAN splash inside isolate_migratepages_range().
Problem is in the function __is_movable_balloon_page() which tests
AS_BALLOON_MAP in page->mapping->flags. This function has no protection
against anonymous pages. As result it tried to check address space flags
inside struct anon_vma.
Further investigation shows more problems in current implementation:
* Special branch in __unmap_and_move() never works:
balloon_page_movable() checks page flags and page_count. In
__unmap_and_move() page is locked, reference counter is elevated, thus
balloon_page_movable() always fails. As a result execution goes to the
normal migration path. virtballoon_migratepage() returns
MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS,
move_to_new_page() thinks this is an error code and assigns
newpage->mapping to NULL. Newly migrated page lose connectivity with
balloon an all ability for further migration.
* lru_lock erroneously required in isolate_migratepages_range() for
isolation ballooned page. This function releases lru_lock periodically,
this makes migration mostly impossible for some pages.
* balloon_page_dequeue have a tight race with balloon_page_isolate:
balloon_page_isolate could be executed in parallel with dequeue between
picking page from list and locking page_lock. Race is rare because they
use trylock_page() for locking.
This patch fixes all of them.
Instead of fake mapping with special flag this patch uses special state of
page->_mapcount: PAGE_BALLOON_MAPCOUNT_VALUE = -256. Buddy allocator uses
PAGE_BUDDY_MAPCOUNT_VALUE = -128 for similar purpose. Storing mark
directly in struct page makes everything safer and easier.
PagePrivate is used to mark pages present in page list (i.e. not
isolated, like PageLRU for normal pages). It replaces special rules for
reference counter and makes balloon migration similar to migration of
normal pages. This flag is protected by page_lock together with link to
the balloon device.
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Reported-by: Sasha Levin <[email protected]>
Link: http://lkml.kernel.org/p/[email protected]
Cc: Rafael Aquini <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: <[email protected]> [3.8+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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bad_page() is cool in that it prints out a bunch of data about the page.
But, I can never remember which page flags are good and which are bad,
or whether ->index or ->mapping is required to be NULL.
This patch allows bad/dump_page() callers to specify a string about why
they are dumping the page and adds explanation strings to a number of
places. It also adds a 'bad_flags' argument to bad_page(), which it
then dumps out separately from the flags which are actually set.
This way, the messages will show specifically why the page was bad,
*specifically* which flags it is complaining about, if it was a page
flag combination which was the problem.
[[email protected]: switch to pr_alert]
Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Christoph Lameter <[email protected]>
Cc: Andi Kleen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Memory fragmentation introduced by ballooning might reduce significantly
the number of 2MB contiguous memory blocks that can be used within a guest,
thus imposing performance penalties associated with the reduced number of
transparent huge pages that could be used by the guest workload.
This patch introduces a common interface to help a balloon driver on
making its page set movable to compaction, and thus allowing the system
to better leverage the compation efforts on memory defragmentation.
[[email protected]: use PAGE_FLAGS_CHECK_AT_PREP, s/__balloon_page_flags/page_flags_cleared/, small cleanups]
[[email protected]: allow balloon compaction for any system with memory compaction enabled, which is the defconfig]
Signed-off-by: Rafael Aquini <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Minchan Kim <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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