Ross Zwisler [Sat, 21 May 2016 00:02:55 +0000 (17:02 -0700)]
radix-tree: fix radix_tree_dump() for multi-order entries
- Print which indices are covered by every leaf entry
- Print sibling entries
- Print the node pointer instead of the slot entry
- Build by default in userspace, and make it accessible to the test-suite
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:52 +0000 (17:02 -0700)]
radix-tree: fix radix_tree_range_tag_if_tagged() for multiorder entries
I had previously decided that tagging a single multiorder entry would
count as tagging 2^order entries for the purposes of 'nr_to_tag'. I now
believe that decision to be a mistake, and it should count as a single
entry. That's more likely to be what callers expect.
When walking back up the tree from a newly-tagged entry, the current
code assumed we were starting from the lowest level of the tree; if we
have a multiorder entry with an order at least RADIX_TREE_MAP_SHIFT in
size then we need to shift the index by 'shift' before we start walking
back up the tree, or we will end up not setting tags on higher entries,
and then mistakenly thinking that entries below a certain point in the
tree are not tagged.
If the first index we examine is a sibling entry of a tagged multiorder
entry, we were not tagging it. We need to examine the canonical entry,
and the easiest way to do that is to use radix_tree_descend(). We then
have to skip over sibling slots when looking for the next entry in the
tree or we will end up walking back to the canonical entry.
Add several tests for radix_tree_range_tag_if_tagged().
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:49 +0000 (17:02 -0700)]
radix-tree: add test for radix_tree_locate_item()
Add a unit test that provides coverage for the bug fixed in the commit
entitled "radix-tree: rewrite radix_tree_locate_item fix" from Hugh
Dickins. I've verified that this test fails before his patch due to
miscalculated 'index' values in __locate() in lib/radix-tree.c, and
passes with his fix.
Matthew Wilcox [Sat, 21 May 2016 00:02:46 +0000 (17:02 -0700)]
radix-tree: rewrite radix_tree_locate_item
Use the new multi-order support functions to rewrite
radix_tree_locate_item(). Modify the locate tests to test multiorder
entries too.
[hughd@google.com: radix_tree_locate_item() is often returning the wrong index] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1605012108490.1166@eggly.anvils Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:44 +0000 (17:02 -0700)]
radix-tree: fix radix_tree_create for sibling entries
If the radix tree user attempted to insert a colliding entry with an
existing multiorder entry, then radix_tree_create() could encounter a
sibling entry when walking down the tree to look for a slot. Use
radix_tree_descend() to fix the problem, and add a test-case to make
sure the problem doesn't come back in future.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:41 +0000 (17:02 -0700)]
radix-tree test suite: add multi-order tag test
Add a generic test for multi-order tag verification, and call it using
several different configurations.
This test creates a multi-order radix tree using the given index and
order, and then sets, checks and clears tags using the indices covered
by the single multi-order radix tree entry.
With the various calls done by this test we verify root multi-order
entries without siblings, multi-order entries without siblings in a
radix tree node, as well as multi-order entries with siblings of various
sizes.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:38 +0000 (17:02 -0700)]
radix-tree: rewrite radix_tree_tag_get
Use the new multi-order support functions to rewrite
radix_tree_tag_get()
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:35 +0000 (17:02 -0700)]
radix-tree: rewrite radix_tree_tag_clear
Use the new multi-order support functions to rewrite
radix_tree_tag_clear()
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:32 +0000 (17:02 -0700)]
radix-tree: rewrite radix_tree_tag_set
Use the new multi-order support functions to rewrite
radix_tree_tag_set()
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:29 +0000 (17:02 -0700)]
radix tree test suite: multi-order iteration test
Add a unit test to verify that we can iterate over multi-order entries
properly via a radix_tree_for_each_slot() loop.
This was done with a single, somewhat complicated configuration that was
meant to test many of the various corner cases having to do with
multi-order entries:
- An iteration could begin at a sibling entry, and we need to return the
canonical entry.
- We could have entries of various orders in the same slots[] array.
- We could have multi-order entries at a nonzero height, followed by
indirect pointers to more radix tree nodes later in that same slots[]
array.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:02:26 +0000 (17:02 -0700)]
radix-tree: add support for multi-order iterating
This enables the macros radix_tree_for_each_slot() and friends to be
used with multi-order entries.
The way that this works is that we treat all entries in a given slots[]
array as a single chunk. If the index given to radix_tree_next_chunk()
happens to point us to a sibling entry, we will back up iter->index so
that it points to the canonical entry, and that will be the place where
we start our iteration.
As we're processing a chunk in radix_tree_next_slot(), we process
canonical entries, skip over sibling entries, and restart the chunk
lookup if we find a non-sibling indirect pointer. This drops back to
the radix_tree_next_chunk() code, which will re-walk the tree and look
for another chunk.
This allows us to properly handle multi-order entries mixed with other
entries that are at various heights in the radix tree.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:23 +0000 (17:02 -0700)]
radix-tree: fix multiorder BUG_ON in radix_tree_insert
These BUG_ON tests are to ensure that all the tags are clear when
inserting a new entry. If we insert a multiorder entry, we'll end up
looking at the tags for a different node, and so the BUG_ON can end up
triggering spuriously.
Also, we now have three tags, not two, so check all three are clear, and
check all the root tags with a single call to BUG_ON since the bits are
stored contiguously.
Include a test-case to ensure this problem does not reoccur.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:20 +0000 (17:02 -0700)]
radix-tree: rewrite __radix_tree_lookup
Use the new multi-order support functions to rewrite __radix_tree_lookup()
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:17 +0000 (17:02 -0700)]
radix-tree: fix several shrinking bugs with multiorder entries
Setting the indirect bit on the user data entry used to be unambiguous
because the tree walking code knew not to expect internal nodes in the
last level of the tree. Multiorder entries can appear at any level of
the tree, and a leaf with the indirect bit set is indistinguishable from
a pointer to a node.
Introduce a special entry (RADIX_TREE_RETRY) which is neither a valid
user entry, nor a valid pointer to a node. The radix_tree_deref_retry()
function continues to work the same way, but tree walking code can
distinguish it from a pointer to a node.
Also fix the condition for setting slot->parent to NULL; it does not
matter what height the tree is, it only matters whether slot is an
indirect pointer. Move this code above the comment which is referring
to the assignment to root->rnode.
Also fix the condition for preventing the tree from shrinking to a
single entry if it's a multiorder entry.
Add a test-case to the test suite that checks that the tree goes back
down to its original height after an item is inserted & deleted from a
higher index in the tree.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:14 +0000 (17:02 -0700)]
radix tree test suite: start adding multiorder tests
Test suite infrastructure for working with multiorder entries.
The test itself is pretty basic: Add an entry, check that all expected
indices return that entry and that indices around that entry don't
return an entry. Then delete the entry and check no index returns that
entry. Tests a few edge conditions including the multiorder entry at
index 0 and at a higher index. Also tests deleting through an alias as
well as through the canonical index.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:11 +0000 (17:02 -0700)]
radix-tree: fix extending the tree for multi-order entries at offset 0
The current code will insert entries at each level, as if we're going to
add a new entry at the bottom level, so we then get an -EEXIST when we
try to insert the entry into the tree. The best way to fix this is to
not check 'order' when inserting into an empty tree.
We still need to 'extend' the tree to the height necessary for the maximum
index corresponding to this entry, so pass that value to
radix_tree_extend() rather than the index we're asked to create, or we
won't create a tree that's deep enough.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:08 +0000 (17:02 -0700)]
radix-tree: introduce radix_tree_load_root()
All the tree walking functions start with some variant of this code;
centralise it in one place so we're not chasing subtly different bugs
everywhere.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:05 +0000 (17:02 -0700)]
radix-tree: remove restriction on multi-order entries
Now that sibling pointers are handled explicitly, there is no purpose
served by restricting the order to be >= RADIX_TREE_MAP_SHIFT.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:02:02 +0000 (17:02 -0700)]
radix-tree: fix deleting a multi-order entry through an alias
If we deleted an entry through an index which looked up a sibling
pointer, we'd end up zeroing out the wrong slots in the node. Use
get_slot_offset() to find the right slot.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:01:59 +0000 (17:01 -0700)]
radix-tree: fix sibling entry insertion
The subtraction was the wrong way round, leading to undefined behaviour
(shift by an amount larger than the size of the type).
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code I previously added to enable multiorder radix tree entries was
untested and therefore buggy. This commit adds the support functions
that Ross and I decided were necessary over a four-week period of
iterating various designs.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I've been receiving increasingly concerned notes from 0day about how
much my recent changes have been bloating the radix tree. Make it
happier by only including multiorder support if
CONFIG_TRANSPARENT_HUGEPAGES is set.
This is an independent Kconfig option, so other radix tree users can
also set it if they have a need.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:01:51 +0000 (17:01 -0700)]
radix-tree: remove unused looping macros
radix_tree_for_each_chunk() and radix_tree_for_each_chunk_slot() have
never been used in the kernel since their introduction in 2012, so
remove them.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:01:48 +0000 (17:01 -0700)]
radix tree test suite: rebuild when headers change
When we make changes to radix-tree.h in the regular kernel source
(include/linux/radix-tree.h), we really want our test code to be
rebuilt.
We also include a few other headers from tools/include and probably want
to rebuild if these have been changed.
Update the makefile so that all of our objects will be rebuilt when any
of the headers we depend on are changed.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:01:45 +0000 (17:01 -0700)]
radix tree test suite: keep regression test runs short
Currently the full suite of regression tests take upwards of 30 minutes
to run on my development machine. The vast majority of this time is
taken by the big_gang_check() and copy_tag_check() tests, which each run
their tests through thousands of iterations...does this have value?
Without big_gang_check() and copy_tag_check(), the test suite runs in
around 15 seconds on my box.
Honestly the first time I ever ran through the entire test suite was to
gather the timings for this email - it simply takes too long to be
useful on a normal basis.
Instead, hide the excessive iterations through big_gang_check() and
copy_tag_check() tests behind an '-l' flag (for "long run") in case they
are still useful, but allow the regression test suite to complete in a
reasonable amount of time. We still run each of these tests a few times
(3 at present) to try and keep the test coverage.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ross Zwisler [Sat, 21 May 2016 00:01:42 +0000 (17:01 -0700)]
radix tree test suite: allow testing other fan-out values
The defines in regression2.c are already in radix-tree.h and duplicating
them in the test case makes experimenting with other values for the
fan-out harder than necessary. Allow the user of the radix tree to
decide what the fan-out should be rather than fixing it to 8 for
non-kernel uses.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:01:39 +0000 (17:01 -0700)]
radix tree test suite: add tests for radix_tree_locate_item()
Fairly simple tests; add various items to the tree, then make sure we
can find them again. Also check that a pointer that we know isn't in
the tree is not found.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:01:36 +0000 (17:01 -0700)]
radix tree test suite: fix build
Add an empty linux/init.h, and definitions for a few parts of the kernel
API either in use now, or to be used in the near future. Start using the
common definitions in tools/include/linux, although more work needs to be
done here.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Matthew Wilcox [Sat, 21 May 2016 00:01:33 +0000 (17:01 -0700)]
radix-tree: introduce radix_tree_empty
Commit e61452365372 ("radix_tree: add support for multi-order entries")
left the impression that the support for multiorder radix tree entries
was functional. As soon as Ross tried to use it, it became apparent
that my testing was completely inadequate, and it didn't even work a
little bit for orders that were not a multiple of shift.
This series of patches is the result of about 6 weeks of redesign,
reimplementation, testing, arguing and hair-pulling. The great news is
that the test-suite is now far better than it was. That's reflected in
the diffstat for the test-suite alone:
The highlight for users of the tree is that the restriction on the order
of inserted entries being >= RADIX_TREE_MAP_SHIFT is now gone; the radix
tree now supports any order between 0 and 64.
For those who are interested in how the tree works, patch 9 is probably
the most interesting one as it introduces the new machinery for handling
sibling entries.
I've tried to be fair in attributing authorship to the person who
contributed the majority of the code in each patch; Ross has been an
invaluable partner in the development of this support and it's fair to
say that each of us has code in every commit.
I should also express my appreciation of the 0day testing. It prompted
me that I was bloating the tinyconfig in an unacceptable way, and it
bisected to a commit which contained a rather nasty memory-corruption
bug.
This patch (of 29):
The irqdomain code was checking for 0 or 1 entries, not 0 entries like
the comment said they were. Introduce a new helper that will actually
check for an empty tree.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy Shevchenko [Sat, 21 May 2016 00:01:18 +0000 (17:01 -0700)]
include/linux/efi.h: redefine type, constant, macro from generic code
Generic UUID library defines structure type, macro to define UUID, and
the length of the UUID string. This patch removes duplicate data
structure definition, UUID string length constant as well as macro for
UUID handling.
Andy Shevchenko [Sat, 21 May 2016 00:01:04 +0000 (17:01 -0700)]
lib/uuid.c: introduce a few more generic helpers
There are new helpers in this patch:
uuid_is_valid checks if a UUID is valid
uuid_be_to_bin converts from string to binary (big endian)
uuid_le_to_bin converts from string to binary (little endian)
They will be used in future, i.e. in the following patches in the series.
This also moves the indices arrays to lib/uuid.c to be shared accross
modules.
Andy Shevchenko [Sat, 21 May 2016 00:00:54 +0000 (17:00 -0700)]
lib/vsprintf: simplify UUID printing
There are few functions here and there along with type definitions that
provide UUID API. This series consolidates everything under one hood
and converts current users.
This has been tested for a while internally, however it doesn't mean we
covered all possible cases (especially accuracy of UUID constants after
conversion). So, please test this as much as you can and provide your
tag. We appreciate the effort.
The ACPI conversion is postponed for now to sort more generic things out
first.
This patch (of 9):
Since we have hex_byte_pack_upper() we may use it directly and avoid
second loop.
Eric Engestrom [Sat, 21 May 2016 00:00:49 +0000 (17:00 -0700)]
MAINTAINERS: remove defunct spear mailing list
It looks like the email address for this mailing list doesn't exist anymore:
<spear-devel@list.st.com>: host mxb-00178001.gslb.pphosted.com[91.207.212.93] said:
550 5.1.1 User Unknown (in reply to RCPT TO command)
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Kalle Valo <kvalo@codeaurora.org> Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jiri Slaby <jslaby@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Sat, 21 May 2016 00:00:42 +0000 (17:00 -0700)]
printk/nmi: flush NMI messages on the system panic
In NMI context, printk() messages are stored into per-CPU buffers to
avoid a possible deadlock. They are normally flushed to the main ring
buffer via an IRQ work. But the work is never called when the system
calls panic() in the very same NMI handler.
This patch tries to flush NMI buffers before the crash dump is
generated. In this case it does not risk a double release and bails out
when the logbuf_lock is already taken. The aim is to get the messages
into the main ring buffer when possible. It makes them better
accessible in the vmcore.
Then the patch tries to flush the buffers second time when other CPUs
are down. It might be more aggressive and reset logbuf_lock. The aim
is to get the messages available for the consequent kmsg_dump() and
console_flush_on_panic() calls.
The patch causes vprintk_emit() to be called even in NMI context again.
But it is done via printk_deferred() so that the console handling is
skipped. Consoles use internal locks and we could not prevent a
deadlock easily. They are explicitly called later when the crash dump
is not generated, see console_flush_on_panic().
Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Sat, 21 May 2016 00:00:39 +0000 (17:00 -0700)]
printk/nmi: increase the size of NMI buffer and make it configurable
Testing has shown that the backtrace sometimes does not fit into the 4kB
temporary buffer that is used in NMI context. The warnings are gone
when I double the temporary buffer size.
This patch doubles the buffer size and makes it configurable.
Note that this problem existed even in the x86-specific implementation
that was added by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI
stack trace on all CPUs"). Nobody noticed it because it did not print
any warnings.
Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Sat, 21 May 2016 00:00:36 +0000 (17:00 -0700)]
printk/nmi: warn when some message has been lost in NMI context
We could not resize the temporary buffer in NMI context. Let's warn if
a message is lost.
This is rather theoretical. printk() should not be used in NMI. The
only sensible use is when we want to print backtrace from all CPUs. The
current buffer should be enough for this purpose.
[akpm@linux-foundation.org: whitespace fixlet] Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Petr Mladek [Sat, 21 May 2016 00:00:33 +0000 (17:00 -0700)]
printk/nmi: generic solution for safe printk in NMI
printk() takes some locks and could not be used a safe way in NMI
context.
The chance of a deadlock is real especially when printing stacks from
all CPUs. This particular problem has been addressed on x86 by the
commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").
The patchset brings two big advantages. First, it makes the NMI
backtraces safe on all architectures for free. Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited. We still should keep the number of messages in NMI context at
minimum).
Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers. These are not easy to avoid.
This patch reuses most of the code and makes it generic. It is useful
for all messages and architectures that support NMI.
The alternative printk_func is set when entering and is reseted when
leaving NMI context. It queues IRQ work to copy the messages into the
main ring buffer in a safe context.
__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers. There is also used a spinlock to get synchronized with other
flushers.
We do not longer use seq_buf because it depends on external lock. It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.
The code is put into separate printk/nmi.c as suggested by Steven
Rostedt. It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter(). This is achieved by the new
HAVE_NMI Kconfig flag.
The are MN10300 and Xtensa architectures. We need to clean up NMI
handling there first. Let's do it separately.
The patch is heavily based on the draft from Peter Zijlstra, see
https://lkml.org/lkml/2015/6/10/327
[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here] Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part] Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/syscalls.h: use pid_t instead of int
In include/linux/syscalls.h, the four functions sys_kill, sys_tgkill,
sys_tkill and sys_rt_sigqueueinfo are declared with "int pid" and "int
tgid".
However, in kernel/signal.c, the corresponding definitions use the more
appropriate "pid_t" (which is a typedef'd int).
This patch changes "int" to "pid_t" in the declarations of sys_kill,
sys_tgkill, sys_tkill and sys_rt_sigqueueinfo in <linux/syscalls.h> in
order to harmonize the function declarations with their respective
definitions.
for (a = 0; a < FORKERS; a++) {
switch ((forkers[a] = fork())) {
case 0:
fork_100_wait();
exit(0);
break;
case -1:
err(1, "DIE fork of %d'th forker", a);
break;
default:
break;
}
}
for (a = 0; a < FORKERS; a++)
waitpid(forkers[a], NULL, 0);
}
int main()
{
unsigned a;
int ret;
ret = ioperm(10, 20, 0);
if (ret < 0)
err(1, "ioperm");
Jiri Slaby [Sat, 21 May 2016 00:00:20 +0000 (17:00 -0700)]
exit_thread: accept a task parameter to be exited
We need to call exit_thread from copy_process in a fail path. So make it
accept task_struct as a parameter.
[v2]
* s390: exit_thread_runtime_instr doesn't make sense to be called for
non-current tasks.
* arm: fix the comment in vfp_thread_copy
* change 'me' to 'tsk' for task_struct
* now we can change only archs that actually have exit_thread
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Howells <dhowells@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonas Bonn <jonas@southpole.se> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mikael Starvik <starvik@axis.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@arm.linux.org.uk> Cc: Steven Miao <realmz6@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jiri Slaby [Sat, 21 May 2016 00:00:11 +0000 (17:00 -0700)]
mn10300: let exit_fpu accept a task
We need to call exit_thread from copy_process in a fail path. Since
exit_thread on mn10300 calls exit_thread_runtime_instr, make it accept
task_struct as a parameter now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Howells <dhowells@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonas Bonn <jonas@southpole.se> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mikael Starvik <starvik@axis.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@arm.linux.org.uk> Cc: Steven Miao <realmz6@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
procfs: fix pthread cross-thread naming if !PR_DUMPABLE
The PR_DUMPABLE flag causes the pid related paths of the proc file
system to be owned by ROOT.
The implementation of pthread_set/getname_np however needs access to
/proc/<pid>/task/<tid>/comm. If PR_DUMPABLE is false this
implementation is locked out.
This patch installs a special permission function for the file "comm"
that grants read and write access to all threads of the same group
regardless of the ownership of the inode. For all other threads the
function falls back to the generic inode permission check.
[akpm@linux-foundation.org: fix spello in comment] Signed-off-by: Janis Danisevskis <jdanis@google.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: David Rientjes <rientjes@google.com> Cc: Minfei Huang <mnfhuang@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Jann Horn <jann@thejh.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not possible to read the process umask without also modifying it,
which is what umask(2) does. A library cannot read umask safely,
especially if the main program might be multithreaded.
Add a new status line ("Umask") in /proc/<PID>/status. It contains the
file mode creation mask (umask) in octal. It is only shown for tasks
which have task->fs.
This patch is adapted from one originally written by Pierre Carrier.
The use case is that we have endless trouble with people setting weird
umask() values (usually on the grounds of "security"), and then
everything breaking. I'm on the hook to fix these. We'd like to add
debugging to our program so we can dump out the umask in debug reports.
Previous versions of the patch used a syscall so you could only read
your own umask. That's all I need. However there was quite a lot of
push-back from those, so this new version exports it in /proc.
debug_stat sysfs is read-only and represents various debugging data that
zram developers may need. This file is not meant to be used by anyone
else: its content is not documented and will change any time w/o any
notice. Therefore, the output of debug_stat file contains a version
string. To avoid any confusion, we will increase the version number
every time we modify the output.
At the moment this file exports only one value -- the number of
re-compressions, IOW, the number of times compression fast path has
failed. This stat is temporary any will be useful in case if any
per-cpu compression streams regressions will be reported.
Remove the internal part of max_comp_streams interface, since we
switched to per-cpu streams. We will keep RW max_comp_streams attr
around, because:
a) we may (silently) switch back to idle compression streams list and
don't want to disturb user space
b) max_comp_streams attr must wait for the next 'lay off cycle'; we
give user space 2 years to adjust before we remove/downgrade the attr,
and there are already several attrs scheduled for removal in 4.11, so
it's too late for max_comp_streams.
This slightly change a user visible behaviour:
- First, reading from max_comp_stream file now will always return the
number of online CPUs.
- Second, writing to max_comp_stream will not take any effect.
Dan Streetman [Fri, 20 May 2016 23:59:56 +0000 (16:59 -0700)]
mm/zsmalloc: don't fail if can't create debugfs info
Change the return type of zs_pool_stat_create() to void, and remove the
logic to abort pool creation if the stat debugfs dir/file could not be
created.
The debugfs stat file is for debugging/information only, and doesn't
affect operation of zsmalloc; there is no reason to abort creating the
pool if the stat file can't be created. This was seen with zswap, which
used the same name for all pool creations, which caused zsmalloc to fail
to create a second pool for zswap if CONFIG_ZSMALLOC_STAT was enabled.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Dan Streetman <dan.streetman@canonical.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Streetman [Fri, 20 May 2016 23:59:54 +0000 (16:59 -0700)]
mm/zswap: use workqueue to destroy pool
Add a work_struct to struct zswap_pool, and change __zswap_pool_empty to
use the workqueue instead of using call_rcu().
When zswap destroys a pool no longer in use, it uses call_rcu() to
perform the destruction/freeing. Since that executes in softirq
context, it must not sleep. However, actually destroying the pool
involves freeing the per-cpu compressors (which requires locking the
cpu_add_remove_lock mutex) and freeing the zpool, for which the
implementation may sleep (e.g. zsmalloc calls kmem_cache_destroy, which
locks the slab_mutex). So if either mutex is currently taken, or any
other part of the compressor or zpool implementation sleeps, it will
result in a BUG().
It's not easy to reproduce this when changing zswap's params normally.
In testing with a loaded system, this does not fail:
Remove idle streams list and keep compression streams in per-cpu data.
This removes two contented spin_lock()/spin_unlock() calls from write
path and also prevent write OP from being preempted while holding the
compression stream, which can cause slow downs.
For instance, let's assume that we have N cpus and N-2
max_comp_streams.TASK1 owns the last idle stream, TASK2-TASK3 come in
with the write requests:
not only TASK2 and TASK3 will not get the stream, TASK1 will be
preempted in the middle of its operation; while we would prefer it to
finish compression and release the stream.
Test environment: x86_64, 4 CPU box, 3G zram, lzo
The following fio tests were executed:
read, randread, write, randwrite, rw, randrw
with the increasing number of jobs from 1 to 10.
Pass GFP flags to zs_malloc() instead of using a fixed mask supplied to
zs_create_pool(), so we can be more flexible, but, more importantly, we
need this to switch zram to per-cpu compression streams -- zram will try
to allocate handle with preemption disabled in a fast path and switch to
a slow path (using different gfp mask) if the fast one has failed.
Apart from that, this also align zs_malloc() interface with zspool/zbud.
[sergey.senozhatsky@gmail.com: pass GFP flags to zs_malloc() instead of using a fixed mask] Link: http://lkml.kernel.org/r/20160429150942.GA637@swordfish Link: http://lkml.kernel.org/r/20160429150942.GA637@swordfish Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minchan Kim [Fri, 20 May 2016 23:59:36 +0000 (16:59 -0700)]
zsmalloc: use first_page rather than page
Clean up function parameter "struct page". Many functions of zsmalloc
expect that page paramter is "first_page" so use "first_page" rather
than "page" for code readability.
Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrey Ryabinin [Fri, 20 May 2016 23:59:31 +0000 (16:59 -0700)]
x86/kasan: instrument user memory access API
Exchange between user and kernel memory is coded in assembly language.
Which means that such accesses won't be spotted by KASAN as a compiler
instruments only C code.
Add explicit KASAN checks to user memory access API to ensure that
userspace writes to (or reads from) a valid kernel memory.
Note: Unlike others strncpy_from_user() is written mostly in C and KASAN
sees memory accesses in it. However, it makes sense to add explicit
check for all @count bytes that *potentially* could be written to the
kernel.
Andrey Ryabinin [Fri, 20 May 2016 23:59:28 +0000 (16:59 -0700)]
mm/kasan: add API to check memory regions
Memory access coded in an assembly won't be seen by KASAN as a compiler
can instrument only C code. Add kasan_check_[read,write]() API which is
going to be used to check a certain memory range.
Link: http://lkml.kernel.org/r/1462538722-1574-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrey Ryabinin [Fri, 20 May 2016 23:59:20 +0000 (16:59 -0700)]
mm/kasan: print name of mem[set,cpy,move]() caller in report
When bogus memory access happens in mem[set,cpy,move]() it's usually
caller's fault. So don't blame mem[set,cpy,move]() in bug report, blame
the caller instead.
Before:
BUG: KASAN: out-of-bounds access in memset+0x23/0x40 at <address>
After:
BUG: KASAN: out-of-bounds access in <memset_caller> at <address>
Link: http://lkml.kernel.org/r/1462538722-1574-2-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quarantine isolates freed objects in a separate queue. The objects are
returned to the allocator later, which helps to detect use-after-free
errors.
When the object is freed, its state changes from KASAN_STATE_ALLOC to
KASAN_STATE_QUARANTINE. The object is poisoned and put into quarantine
instead of being returned to the allocator, therefore every subsequent
access to that object triggers a KASAN error, and the error handler is
able to say where the object has been allocated and deallocated.
When it's time for the object to leave quarantine, its state becomes
KASAN_STATE_FREE and it's returned to the allocator. From now on the
allocator may reuse it for another allocation. Before that happens,
it's still possible to detect a use-after free on that object (it
retains the allocation/deallocation stacks).
When the allocator reuses this object, the shadow is unpoisoned and old
allocation/deallocation stacks are wiped. Therefore a use of this
object, even an incorrect one, won't trigger ASan warning.
Without the quarantine, it's not guaranteed that the objects aren't
reused immediately, that's why the probability of catching a
use-after-free is lower than with quarantine in place.
Quarantine isolates freed objects in a separate queue. The objects are
returned to the allocator later, which helps to detect use-after-free
errors.
Freed objects are first added to per-cpu quarantine queues. When a
cache is destroyed or memory shrinking is requested, the objects are
moved into the global quarantine queue. Whenever a kmalloc call allows
memory reclaiming, the oldest objects are popped out of the global queue
until the total size of objects in quarantine is less than 3/4 of the
maximum quarantine size (which is a fraction of installed physical
memory).
As long as an object remains in the quarantine, KASAN is able to report
accesses to it, so the chance of reporting a use-after-free is
increased. Once the object leaves quarantine, the allocator may reuse
it, in which case the object is unpoisoned and KASAN can't detect
incorrect accesses to it.
Right now quarantine support is only enabled in SLAB allocator.
Unification of KASAN features in SLAB and SLUB will be done later.
This patch is based on the "mm: kasan: quarantine" patch originally
prepared by Dmitry Chernenkov. A number of improvements have been
suggested by Andrey Ryabinin.
[glider@google.com: v9] Link: http://lkml.kernel.org/r/1462987130-144092-1-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yang Shi [Fri, 20 May 2016 23:59:08 +0000 (16:59 -0700)]
mm: call page_ext_init() after all struct pages are initialized
When DEFERRED_STRUCT_PAGE_INIT is enabled, just a subset of memmap at
boot are initialized, then the rest are initialized in parallel by
starting one-off "pgdatinitX" kernel thread for each node X.
If page_ext_init is called before it, some pages will not have valid
extension, this may lead the below kernel oops when booting up kernel:
David Rientjes [Fri, 20 May 2016 23:59:05 +0000 (16:59 -0700)]
mm, migrate: increment fail count on ENOMEM
If page migration fails due to -ENOMEM, nr_failed should still be
incremented for proper statistics.
This was encountered recently when all page migration vmstats showed 0,
and inferred that migrate_pages() was never called, although in reality
the first page migration failed because compaction_alloc() failed to
find a migration target.
This patch increments nr_failed so the vmstat is properly accounted on
ENOMEM.
Chen Feng [Fri, 20 May 2016 23:59:02 +0000 (16:59 -0700)]
mm/compaction.c: fix zoneindex in kcompactd()
While testing the kcompactd in my platform 3G MEM only DMA ZONE. I
found the kcompactd never wakeup. It seems the zoneindex has already
minus 1 before. So the traverse here should be <=.
It fixes a regression where kswapd could previously compact, but
kcompactd not. Not a crash fix though.
[akpm@linux-foundation.org: fix kcompactd_do_work() as well, per Hugh] Link: http://lkml.kernel.org/r/1463659121-84124-1-git-send-email-puck.chen@hisilicon.com Fixes: accf62422b3a ("mm, kswapd: replace kswapd compaction with waking up kcompactd") Signed-off-by: Chen Feng <puck.chen@hisilicon.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zhuangluan Su <suzhuangluan@hisilicon.com> Cc: Yiping Xu <xuyiping@hisilicon.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The problem is lookup_page_ext() returns NULL then page_is_guard() tried
to access it in page freeing.
page_is_guard() depends on PAGE_EXT_DEBUG_GUARD bit of page extension
flag, but freeing page might reach here before the page_ext arrays are
allocated when feeding a range of pages to the allocator for the first
time during bootup or memory hotplug.
When it returns NULL, page_is_guard() should just return false instead
of checking PAGE_EXT_DEBUG_GUARD unconditionally.
Link: http://lkml.kernel.org/r/1463610225-29060-1-git-send-email-yang.shi@linaro.org Signed-off-by: Yang Shi <yang.shi@linaro.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NeilBrown [Fri, 20 May 2016 23:58:53 +0000 (16:58 -0700)]
MM: increase safety margin provided by PF_LESS_THROTTLE
When nfsd is exporting a filesystem over NFS which is then NFS-mounted
on the local machine there is a risk of deadlock. This happens when
there are lots of dirty pages in the NFS filesystem and they cause NFSD
to be throttled, either in throttle_vm_writeout() or in
balance_dirty_pages().
To avoid this problem the PF_LESS_THROTTLE flag is set for NFSD threads
and it provides a 25% increase to the limits that affect NFSD. Any
process writing to an NFS filesystem will be throttled well before the
number of dirty NFS pages reaches the limit imposed on NFSD, so NFSD
will not deadlock on pages that it needs to write out. At least it
shouldn't.
All processes are allowed a small excess margin to avoid performing too
many calculations: ratelimit_pages.
ratelimit_pages is set so that if a thread on every CPU uses the entire
margin, the total will only go 3% over the limit, and this is much less
than the 25% bonus that PF_LESS_THROTTLE provides, so this margin
shouldn't be a problem. But it is.
The "total memory" that these 3% and 25% are calculated against are not
really total memory but are "global_dirtyable_memory()" which doesn't
include anonymous memory, just free memory and page-cache memory.
The "ratelimit_pages" number is based on whatever the
global_dirtyable_memory was on the last CPU hot-plug, which might not be
what you expect, but is probably close to the total freeable memory.
The throttle threshold uses the global_dirtable_memory at the moment
when the throttling happens, which could be much less than at the last
CPU hotplug. So if lots of anonymous memory has been allocated, thus
pushing out lots of page-cache pages, then NFSD might end up being
throttled due to dirty NFS pages because the "25%" bonus it gets is
calculated against a rather small amount of dirtyable memory, while the
"3%" margin that other processes are allowed to dirty without penalty is
calculated against a much larger number.
To remove this possibility of deadlock we need to make sure that the
margin granted to PF_LESS_THROTTLE exceeds that rate-limit margin.
Simply adding ratelimit_pages isn't enough as that should be multiplied
by the number of cpus.
So add "global_wb_domain.dirty_limit / 32" as that more accurately
reflects the current total over-shoot margin. This ensures that the
number of dirty NFS pages never gets so high that nfsd will be throttled
waiting for them to be written.
Naoya Horiguchi [Fri, 20 May 2016 23:58:50 +0000 (16:58 -0700)]
mm: check_new_page_bad() directly returns in __PG_HWPOISON case
Currently we check page->flags twice for "HWPoisoned" case of
check_new_page_bad(), which can cause a race with unpoisoning.
This race unnecessarily taints kernel with "BUG: Bad page state".
check_new_page_bad() is the only caller of bad_page() which is
interested in __PG_HWPOISON, so let's move the hwpoison related code in
bad_page() to it.
seokhoon.yoon [Fri, 20 May 2016 23:58:47 +0000 (16:58 -0700)]
mm, kasan: fix to call kasan_free_pages() after poisoning page
When CONFIG_PAGE_POISONING and CONFIG_KASAN is enabled,
free_pages_prepare()'s codeflow is below.
1)kmemcheck_free_shadow()
2)kasan_free_pages()
- set shadow byte of page is freed
3)kernel_poison_pages()
3.1) check access to page is valid or not using kasan
---> error occur, kasan think it is invalid access
3.2) poison page
4)kernel_map_pages()
So kasan_free_pages() should be called after poisoning the page.
Minchan Kim [Fri, 20 May 2016 23:58:44 +0000 (16:58 -0700)]
mm: disable fault around on emulated access bit architecture
fault_around aims to reduce minor faults of file-backed pages via
speculative ahead pte mapping and relying on readahead logic. However,
on non-HW access bit architecture the benefit is highly limited because
they should emulate the young bit with minor faults for reclaim's page
aging algorithm. IOW, we cannot reduce minor faults on those
architectures.
I did quick a test on my ARM machine.
512M file mmap sequential every word read on eSATA drive 4 times.
stddev is stable.
Even when I tested it with eMMC there is no gain because I guess with
slow storage the major fault is the dominant factor.
Also, fault_around has the side effect of shrinking slab more
aggressively and causes higher vmpressure, so if such speculation fails,
it can evict slab more which can result in page I/O (e.g., inode cache).
In the end, it would make void any benefit of fault_around.
So let's make the default "disabled" on those architectures.
Link: http://lkml.kernel.org/r/20160518014229.GB21538@bbox Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, faultaround code produces young pte. This can screw up
vmscan behaviour[1], as it makes vmscan think that these pages are hot
and not push them out on first round.
During sparse file access faultaround gets more pages mapped and all of
them are young. Under memory pressure, this makes vmscan swap out anon
pages instead, or to drop other page cache pages which otherwise stay
resident.
Modify faultaround to produce old ptes, so they can easily be reclaimed
under memory pressure.
This can to some extend defeat the purpose of faultaround on machines
without hardware accessed bit as it will not help us with reducing the
number of minor page faults.
We may want to disable faultaround on such machines altogether, but
that's subject for separate patchset.
Minchan:
"I tested 512M mmap sequential word read test on non-HW access bit
system (i.e., ARM) and confirmed it doesn't increase minor fault any
more.
old: 4096 fault_around
minor fault: 131291
elapsed time: 6747645 usec
new: 65536 fault_around
minor fault: 131291
elapsed time: 6709263 usec
Stefan Bader [Fri, 20 May 2016 23:58:38 +0000 (16:58 -0700)]
mm: use phys_addr_t for reserve_bootmem_region() arguments
Since commit 92923ca3aace ("mm: meminit: only set page reserved in the
memblock region") the reserved bit is set on reserved memblock regions.
However start and end address are passed as unsigned long. This is only
32bit on i386, so it can end up marking the wrong pages reserved for
ranges at 4GB and above.
This was observed on a 32bit Xen dom0 which was booted with initial
memory set to a value below 4G but allowing to balloon in memory
(dom0_mem=1024M for example). This would define a reserved bootmem
region for the additional memory (for example on a 8GB system there was
a reverved region covering the 4GB-8GB range). But since the addresses
were passed on as unsigned long, this was actually marking all pages
from 0 to 4GB as reserved.
Fixes: 92923ca3aacef63 ("mm: meminit: only set page reserved in the memblock region") Link: http://lkml.kernel.org/r/1463491221-10573-1-git-send-email-stefan.bader@canonical.com Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Cc: <stable@vger.kernel.org> [4.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg Nesterov [Fri, 20 May 2016 23:58:36 +0000 (16:58 -0700)]
userfaultfd: don't pin the user memory in userfaultfd_file_create()
userfaultfd_file_create() increments mm->mm_users; this means that the
memory won't be unmapped/freed if mm owner exits/execs, and UFFDIO_COPY
after that can populate the orphaned mm more.
Change userfaultfd_file_create() and userfaultfd_ctx_put() to use
mm->mm_count to pin mm_struct. This means that
atomic_inc_not_zero(mm->mm_users) is needed when we are going to
actually play with this memory. Except handle_userfault() path doesn't
need this, the caller must already have a reference.
The patch adds the new trivial helper, mmget_not_zero(), it can have
more users.
Link: http://lkml.kernel.org/r/20160516172254.GA8595@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Comparing an u64 variable to >= 0 returns always true and can therefore
be removed. This issue was detected using the -Wtype-limits gcc flag.
This patch fixes following type-limits warning:
mm/memblock.c: In function `__next_reserved_mem_region':
mm/memblock.c:843:11: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
if (*idx >= 0 && *idx < type->cnt) {
Vitaly Wool [Fri, 20 May 2016 23:58:30 +0000 (16:58 -0700)]
z3fold: the 3-fold allocator for compressed pages
This patch introduces z3fold, a special purpose allocator for storing
compressed pages. It is designed to store up to three compressed pages
per physical page. It is a ZBUD derivative which allows for higher
compression ratio keeping the simplicity and determinism of its
predecessor.
This patch comes as a follow-up to the discussions at the Embedded Linux
Conference in San-Diego related to the talk [1]. The outcome of these
discussions was that it would be good to have a compressed page
allocator as stable and deterministic as zbud with with higher
compression ratio.
To keep the determinism and simplicity, z3fold, just like zbud, always
stores an integral number of compressed pages per page, but it can store
up to 3 pages unlike zbud which can store at most 2. Therefore the
compression ratio goes to around 2.6x while zbud's one is around 1.7x.
The patch is based on the latest linux.git tree.
This version has been updated after testing on various simulators (e.g.
ARM Versatile Express, MIPS Malta, x86_64/Haswell) and basing on
comments from Dan Streetman [3].
Andrea Arcangeli [Fri, 20 May 2016 23:58:24 +0000 (16:58 -0700)]
mm: thp: microoptimize compound_mapcount()
compound_mapcount() is only called after PageCompound() has already been
checked by the caller, so there's no point to check it again. Gcc may
optimize it away too because it's inline but this will remove the
runtime check for sure and add it'll add an assert instead.
Link: http://lkml.kernel.org/r/1462547040-1737-3-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The cpu_stat_off variable is unecessary since we can check if a
workqueue request is pending otherwise. Removal of cpu_stat_off makes
it pretty easy for the vmstat shepherd to ensure that the proper things
happen.
Removing the state also removes all races related to it. Should a
workqueue not be scheduled as needed for vmstat_update then the shepherd
will notice and schedule it as needed. Should a workqueue be
unecessarily scheduled then the vmstat updater will disable it.
[akpm@linux-foundation.org: fix indentation, per Michal] Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1605061306460.17934@east.gentwo.org Signed-off-by: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Michal Hocko <mhocko@suse.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>
Tetsuo Handa [Fri, 20 May 2016 23:58:10 +0000 (16:58 -0700)]
mm,writeback: don't use memory reserves for wb_start_writeback
When writeback operation cannot make forward progress because memory
allocation requests needed for doing I/O cannot be satisfied (e.g.
under OOM-livelock situation), we can observe flood of order-0 page
allocation failure messages caused by complete depletion of memory
reserves.
This is caused by unconditionally allocating "struct wb_writeback_work"
objects using GFP_ATOMIC from PF_MEMALLOC context.
Since I/O is stalling, allocating writeback requests forever shall
deplete memory reserves. Fortunately, since wb_start_writeback() can
fall back to wb_wakeup() when allocating "struct wb_writeback_work"
failed, we don't need to allow wb_start_writeback() to use memory
reserves.
Assuming that somebody will find a better solution, let's apply this
patch for now to stop bleeding, for this problem frequently prevents me
from testing OOM livelock condition.
Link: http://lkml.kernel.org/r/20160318131136.GE7152@quack.suse.cz Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ming Li [Fri, 20 May 2016 23:57:56 +0000 (16:57 -0700)]
mm/swap.c: put activate_page_pvecs and other pagevecs together
Put the activate_page_pvecs definition next to those of the other
pagevecs, for clarity.
Signed-off-by: Ming Li <mingli199x@qq.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Fri, 20 May 2016 23:57:50 +0000 (16:57 -0700)]
mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size
The page_counter rounds limits down to page size values. This makes
sense, except in the case of hugetlb_cgroup where it's not possible to
charge partial hugepages. If the hugetlb_cgroup margin is less than the
hugepage size being charged, it will fail as expected.
Round the hugetlb_cgroup limit down to hugepage size, since it is the
effective limit of the cgroup.
For consistency, round down PAGE_COUNTER_MAX as well when a
hugetlb_cgroup is created: this prevents error reports when a user
cannot restore the value to the kernel default.
Signed-off-by: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nikolay Borisov <kernel@kyup.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rich Felker [Fri, 20 May 2016 23:57:47 +0000 (16:57 -0700)]
tmpfs/ramfs: fix VM_MAYSHARE mappings for NOMMU
The nommu do_mmap expects f_op->get_unmapped_area to either succeed or
return -ENOSYS for VM_MAYSHARE (e.g. private read-only) mappings.
Returning addr in the non-MAP_SHARED case was completely wrong, and only
happened to work because addr was 0. However, it prevented VM_MAYSHARE
mappings from sharing backing with the fs cache, and forced such
mappings (including shareable program text) to be copied whenever the
number of mappings transitioned from 0 to 1, impacting performance and
memory usage. Subsequent mappings beyond the first still correctly
shared memory with the first.
Instead, treat VM_MAYSHARE identically to VM_SHARED at the file ops level;
do_mmap already handles the semantic differences between them.
Signed-off-by: Rich Felker <dalias@libc.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>