Pull misc updates from Andrew Morton:
"The non-MM patch queue for this merge window.
Not a lot of material this cycle. Many singleton patches against
various subsystems. Most notably some maintenance work in ocfs2
and initramfs"
* tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits)
kcov: update pos before writing pc in trace function
ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock
fs/ntfs: remove redundant variable idx
fat: remove time truncations in vfat_create/vfat_mkdir
fat: report creation time in statx
fat: ignore ctime updates, and keep ctime identical to mtime in memory
fat: split fat_truncate_time() into separate functions
MAINTAINERS: add Muchun as a memcg reviewer
proc/sysctl: make protected_* world readable
ia64: mca: drop redundant spinlock initialization
tty: fix deadlock caused by calling printk() under tty_port->lock
relay: remove redundant assignment to pointer buf
fs/ntfs3: validate BOOT sectors_per_clusters
lib/string_helpers: fix not adding strarray to device's resource list
kernel/crash_core.c: remove redundant check of ck_cmdline
ELF, uapi: fixup ELF_ST_TYPE definition
ipc/mqueue: use get_tree_nodev() in mqueue_get_tree()
ipc: update semtimedop() to use hrtimer
ipc/sem: remove redundant assignments
...
There's a locking issue with the per-netns list of calls in rxrpc. The
pieces of code that add and remove a call from the list use write_lock()
and the calls procfile uses read_lock() to access it. However, the timer
callback function may trigger a removal by trying to queue a call for
processing and finding that it's already queued - at which point it has a
spare refcount that it has to do something with. Unfortunately, if it puts
the call and this reduces the refcount to 0, the call will be removed from
the list. Unfortunately, since the _bh variants of the locking functions
aren't used, this can deadlock.
================================
WARNING: inconsistent lock state
5.18.0-rc3-build4+ #10 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
ksoftirqd/2/25 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffff888107ac4038 (&rxnet->call_lock){+.?.}-{2:2}, at: rxrpc_put_call+0x103/0x14b
{SOFTIRQ-ON-W} state was registered at:
...
Possible unsafe locking scenario:
CPU0
----
lock(&rxnet->call_lock);
<Interrupt>
lock(&rxnet->call_lock);
*** DEADLOCK ***
1 lock held by ksoftirqd/2/25:
#0: ffff8881008ffdb0 ((&call->timer)){+.-.}-{0:0}, at: call_timer_fn+0x5/0x23d
Changes
=======
ver #2)
- Changed to using list_next_rcu() rather than rcu_dereference() directly.
Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Add macros to get the next or previous entries and wraparound if
needed. For example, calling list_next_entry_circular() on the last
element should return the first element in the list.
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ep_poll() first calls ep_events_available() with no lock held and checks
if ep->rdllist is empty by list_empty_careful(), which reads
rdllist->prev. Thus all accesses to it need some protection to avoid
store/load-tearing.
Note INIT_LIST_HEAD_RCU() already has the annotation for both prev
and next.
Commit bf3b9f6372 ("epoll: Add busy poll support to epoll with socket
fds.") added the first lockless ep_events_available(), and commit
c5a282e963 ("fs/epoll: reduce the scope of wq lock in epoll_wait()")
made some ep_events_available() calls lockless and added single call under
a lock, finally commit e59d3c64cb ("epoll: eliminate unnecessary lock
for zero timeout") made the last ep_events_available() lockless.
BUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait
write to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0:
INIT_LIST_HEAD include/linux/list.h:38 [inline]
list_splice_init include/linux/list.h:492 [inline]
ep_start_scan fs/eventpoll.c:622 [inline]
ep_send_events fs/eventpoll.c:1656 [inline]
ep_poll fs/eventpoll.c:1806 [inline]
do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234
do_epoll_pwait fs/eventpoll.c:2268 [inline]
__do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]
__se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275
__x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1:
list_empty_careful include/linux/list.h:329 [inline]
ep_events_available fs/eventpoll.c:381 [inline]
ep_poll fs/eventpoll.c:1797 [inline]
do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234
do_epoll_pwait fs/eventpoll.c:2268 [inline]
__do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]
__se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275
__x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0xffff88810480c7d0 -> 0xffff888103c15098
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G W 5.17.0-rc7-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Link: https://lkml.kernel.org/r/20220322002653.33865-3-kuniyu@amazon.co.jp
Fixes: e59d3c64cb ("epoll: eliminate unnecessary lock for zero timeout")
Fixes: c5a282e963 ("fs/epoll: reduce the scope of wq lock in epoll_wait()")
Fixes: bf3b9f6372 ("epoll: Add busy poll support to epoll with socket fds.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Reported-by: syzbot+bdd6e38a1ed5ee58d8bd@syzkaller.appspotmail.com
Cc: Al Viro <viro@zeniv.linux.org.uk>, Andrew Morton <akpm@linux-foundation.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Cc: Kuniyuki Iwashima <kuni1840@gmail.com>
Cc: "Soheil Hassas Yeganeh" <soheil@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Sridhar Samudrala" <sridhar.samudrala@intel.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The students in the Operating System Lecture Section at the
American University of Sharjah were confused by the header comment
in include/linux/list.h, which says "Simple doubly linked list
implementation". This comment means "simple" as in "not complex",
but "simple" is often used in this context to mean "not circular".
This commit therefore avoids this ambiguity by explicitly calling out
"circular".
Signed-off-by: Asif Rasheed <b00073877@aus.edu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
hash_for_each_safe() and hash_for_each_possible_safe()
need to be passed a temp 'struct hlist_node' pointer, but
do not say that in the documentation - they just say
a 'struct'.
Also the documentation for hlist_for_each_entry_safe()
describes @n as "another" hlist_node, but in reality it is
the only one.
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Pull RCU updates from Ingo Molnar:
"The RCU changes in this cycle were:
- Expedited grace-period updates
- kfree_rcu() updates
- RCU list updates
- Preemptible RCU updates
- Torture-test updates
- Miscellaneous fixes
- Documentation updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
rcu: Remove unused stop-machine #include
powerpc: Remove comment about read_barrier_depends()
.mailmap: Add entries for old paulmck@kernel.org addresses
srcu: Apply *_ONCE() to ->srcu_last_gp_end
rcu: Switch force_qs_rnp() to for_each_leaf_node_cpu_mask()
rcu: Move rcu_{expedited,normal} definitions into rcupdate.h
rcu: Move gp_state_names[] and gp_state_getname() to tree_stall.h
rcu: Remove the declaration of call_rcu() in tree.h
rcu: Fix tracepoint tracking RCU CPU kthread utilization
rcu: Fix harmless omission of "CONFIG_" from #if condition
rcu: Avoid tick_dep_set_cpu() misordering
rcu: Provide wrappers for uses of ->rcu_read_lock_nesting
rcu: Use READ_ONCE() for ->expmask in rcu_read_unlock_special()
rcu: Clear ->rcu_read_unlock_special only once
rcu: Clear .exp_hint only when deferred quiescent state has been reported
rcu: Rename some instance of CONFIG_PREEMPTION to CONFIG_PREEMPT_RCU
rcu: Remove kfree_call_rcu_nobatch()
rcu: Remove kfree_rcu() special casing and lazy-callback handling
rcu: Add support for debug_objects debugging for kfree_rcu()
rcu: Add multiple in-flight batches of kfree_rcu() work
...
As other *continue() helpers, this continues iteration from a given
position.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We would like to use hlist_unhashed() from timer_pending(),
which runs without protection of a lock.
Note that other callers might also want to use this variant.
Instead of forcing a READ_ONCE() for all hlist_unhashed()
callers, add a new helper with an explicit _lockless suffix
in the name to better document what is going on.
Also add various WRITE_ONCE() in __hlist_del(), hlist_add_head()
and hlist_add_before()/hlist_add_behind() to pair with
the READ_ONCE().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
[ paulmck: Also add WRITE_ONCE() to rculist.h. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Add a helper in list.h for the non-standard way of clearing a list that is
used in xskmap. This makes it easier to reuse it in the other map types,
and also makes sure this usage is not forgotten in any list refactorings in
the future.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Pull device mapper updates from Mike Snitzer:
- Improve DM snapshot target's scalability by using finer grained
locking. Requires some list_bl interface improvements.
- Add ability for DM integrity to use a bitmap mode, that tracks
regions where data and metadata are out of sync, instead of using a
journal.
- Improve DM thin provisioning target to not write metadata changes to
disk if the thin-pool and associated thin devices are merely
activated but not used. This avoids metadata corruption due to
concurrent activation of thin devices across different OS instances
(e.g. split brain scenarios, which ultimately would be avoided if
proper device filters were used -- but not having proper filtering
has proven a very common configuration mistake)
- Fix missing call to path selector type->end_io in DM multipath. This
fixes reported performance problems due to inaccurate path selector
IO accounting causing an imbalance of IO (e.g. avoiding issuing IO to
particular path due to it seemingly being heavily used).
- Fix bug in DM cache metadata's loading of its discard bitset that
could lead to all cache blocks being discarded if the very first
cache block was discarded (thankfully in practice the first cache
block is generally in use; be it FS superblock, partition table, disk
label, etc).
- Add testing-only DM dust target which simulates a device that has
failing sectors and/or read failures.
- Fix a DM init error path reference count hang that caused boot hangs
if user supplied malformed input on kernel commandline.
- Fix a couple issues with DM crypt target's logging being overly
verbose or lacking context.
- Various other small fixes to DM init, DM multipath, DM zoned, and DM
crypt.
* tag 'for-5.2/dm-changes-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (42 commits)
dm: fix a couple brace coding style issues
dm crypt: print device name in integrity error message
dm crypt: move detailed message into debug level
dm ioctl: fix hang in early create error condition
dm integrity: whitespace, coding style and dead code cleanup
dm integrity: implement synchronous mode for reboot handling
dm integrity: handle machine reboot in bitmap mode
dm integrity: add a bitmap mode
dm integrity: introduce a function add_new_range_and_wait()
dm integrity: allow large ranges to be described
dm ingerity: pass size to dm_integrity_alloc_page_list()
dm integrity: introduce rw_journal_sectors()
dm integrity: update documentation
dm integrity: don't report unused options
dm integrity: don't check null pointer before kvfree and vfree
dm integrity: correctly calculate the size of metadata area
dm dust: Make dm_dust_init and dm_dust_exit static
dm dust: remove redundant unsigned comparison to less than zero
dm mpath: always free attached_handler_name in parse_path()
dm init: fix max devices/targets checks
...
Patch series "mm: Randomize free memory", v10.
This patch (of 3):
Randomization of the page allocator improves the average utilization of
a direct-mapped memory-side-cache. Memory side caching is a platform
capability that Linux has been previously exposed to in HPC
(high-performance computing) environments on specialty platforms. In
that instance it was a smaller pool of high-bandwidth-memory relative to
higher-capacity / lower-bandwidth DRAM. Now, this capability is going
to be found on general purpose server platforms where DRAM is a cache in
front of higher latency persistent memory [1].
Robert offered an explanation of the state of the art of Linux
interactions with memory-side-caches [2], and I copy it here:
It's been a problem in the HPC space:
http://www.nersc.gov/research-and-development/knl-cache-mode-performance-coe/
A kernel module called zonesort is available to try to help:
https://software.intel.com/en-us/articles/xeon-phi-software
and this abandoned patch series proposed that for the kernel:
https://lkml.kernel.org/r/20170823100205.17311-1-lukasz.daniluk@intel.com
Dan's patch series doesn't attempt to ensure buffers won't conflict, but
also reduces the chance that the buffers will. This will make performance
more consistent, albeit slower than "optimal" (which is near impossible
to attain in a general-purpose kernel). That's better than forcing
users to deploy remedies like:
"To eliminate this gradual degradation, we have added a Stream
measurement to the Node Health Check that follows each job;
nodes are rebooted whenever their measured memory bandwidth
falls below 300 GB/s."
A replacement for zonesort was merged upstream in commit cc9aec03e5
("x86/numa_emulation: Introduce uniform split capability"). With this
numa_emulation capability, memory can be split into cache sized
("near-memory" sized) numa nodes. A bind operation to such a node, and
disabling workloads on other nodes, enables full cache performance.
However, once the workload exceeds the cache size then cache conflicts
are unavoidable. While HPC environments might be able to tolerate
time-scheduling of cache sized workloads, for general purpose server
platforms, the oversubscribed cache case will be the common case.
The worst case scenario is that a server system owner benchmarks a
workload at boot with an un-contended cache only to see that performance
degrade over time, even below the average cache performance due to
excessive conflicts. Randomization clips the peaks and fills in the
valleys of cache utilization to yield steady average performance.
Here are some performance impact details of the patches:
1/ An Intel internal synthetic memory bandwidth measurement tool, saw a
3X speedup in a contrived case that tries to force cache conflicts.
The contrived cased used the numa_emulation capability to force an
instance of the benchmark to be run in two of the near-memory sized
numa nodes. If both instances were placed on the same emulated they
would fit and cause zero conflicts. While on separate emulated nodes
without randomization they underutilized the cache and conflicted
unnecessarily due to the in-order allocation per node.
2/ A well known Java server application benchmark was run with a heap
size that exceeded cache size by 3X. The cache conflict rate was 8%
for the first run and degraded to 21% after page allocator aging. With
randomization enabled the rate levelled out at 11%.
3/ A MongoDB workload did not observe measurable difference in
cache-conflict rates, but the overall throughput dropped by 7% with
randomization in one case.
4/ Mel Gorman ran his suite of performance workloads with randomization
enabled on platforms without a memory-side-cache and saw a mix of some
improvements and some losses [3].
While there is potentially significant improvement for applications that
depend on low latency access across a wide working-set, the performance
may be negligible to negative for other workloads. For this reason the
shuffle capability defaults to off unless a direct-mapped
memory-side-cache is detected. Even then, the page_alloc.shuffle=0
parameter can be specified to disable the randomization on those systems.
Outside of memory-side-cache utilization concerns there is potentially
security benefit from randomization. Some data exfiltration and
return-oriented-programming attacks rely on the ability to infer the
location of sensitive data objects. The kernel page allocator, especially
early in system boot, has predictable first-in-first out behavior for
physical pages. Pages are freed in physical address order when first
onlined.
Quoting Kees:
"While we already have a base-address randomization
(CONFIG_RANDOMIZE_MEMORY), attacks against the same hardware and
memory layouts would certainly be using the predictability of
allocation ordering (i.e. for attacks where the base address isn't
important: only the relative positions between allocated memory).
This is common in lots of heap-style attacks. They try to gain
control over ordering by spraying allocations, etc.
I'd really like to see this because it gives us something similar
to CONFIG_SLAB_FREELIST_RANDOM but for the page allocator."
While SLAB_FREELIST_RANDOM reduces the predictability of some local slab
caches it leaves vast bulk of memory to be predictably in order allocated.
However, it should be noted, the concrete security benefits are hard to
quantify, and no known CVE is mitigated by this randomization.
Introduce shuffle_free_memory(), and its helper shuffle_zone(), to perform
a Fisher-Yates shuffle of the page allocator 'free_area' lists when they
are initially populated with free memory at boot and at hotplug time. Do
this based on either the presence of a page_alloc.shuffle=Y command line
parameter, or autodetection of a memory-side-cache (to be added in a
follow-on patch).
The shuffling is done in terms of CONFIG_SHUFFLE_PAGE_ORDER sized free
pages where the default CONFIG_SHUFFLE_PAGE_ORDER is MAX_ORDER-1 i.e. 10,
4MB this trades off randomization granularity for time spent shuffling.
MAX_ORDER-1 was chosen to be minimally invasive to the page allocator
while still showing memory-side cache behavior improvements, and the
expectation that the security implications of finer granularity
randomization is mitigated by CONFIG_SLAB_FREELIST_RANDOM. The
performance impact of the shuffling appears to be in the noise compared to
other memory initialization work.
This initial randomization can be undone over time so a follow-on patch is
introduced to inject entropy on page free decisions. It is reasonable to
ask if the page free entropy is sufficient, but it is not enough due to
the in-order initial freeing of pages. At the start of that process
putting page1 in front or behind page0 still keeps them close together,
page2 is still near page1 and has a high chance of being adjacent. As
more pages are added ordering diversity improves, but there is still high
page locality for the low address pages and this leads to no significant
impact to the cache conflict rate.
[1]: https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/
[2]: https://lkml.kernel.org/r/AT5PR8401MB1169D656C8B5E121752FC0F8AB120@AT5PR8401MB1169.NAMPRD84.PROD.OUTLOOK.COM
[3]: https://lkml.org/lkml/2018/10/12/309
[dan.j.williams@intel.com: fix shuffle enable]
Link: http://lkml.kernel.org/r/154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com
[cai@lca.pw: fix SHUFFLE_PAGE_ALLOCATOR help texts]
Link: http://lkml.kernel.org/r/20190425201300.75650-1-cai@lca.pw
Link: http://lkml.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: Use slab_list list_head instead of lru", v5.
Currently the slab allocators (ab)use the struct page 'lru' list_head. We
have a list head for slab allocators to use, 'slab_list'.
During v2 it was noted by Christoph that the SLOB allocator was reaching
into a list_head, this version adds 2 patches to the front of the set to
fix that.
Clean up all three allocators by using the 'slab_list' list_head instead
of overloading the 'lru' list_head.
This patch (of 7):
Currently if we wish to rotate a list until a specific item is at the
front of the list we can call list_move_tail(head, list). Note that the
arguments are the reverse way to the usual use of list_move_tail(list,
head). This is a hack, it depends on the developer knowing how the
list_head operates internally which violates the layer of abstraction
offered by the list_head. Also, it is not intuitive so the next developer
to come along must study list.h in order to fully understand what is meant
by the call, while this is 'good for' the developer it makes reading the
code harder. We should have an function appropriately named that does
this if there are users for it intree.
By grep'ing the tree for list_move_tail() and list_tail() and attempting
to guess the argument order from the names it seems there is only one
place currently in the tree that does this - the slob allocatator.
Add function list_rotate_to_front() to rotate a list until the specified
item is at the front of the list.
Link: http://lkml.kernel.org/r/20190402230545.2929-2-tobin@kernel.org
Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 1c97be677f ("list: Use WRITE_ONCE() when adding to lists and
hlists") introduced the use of WRITE_ONCE() to atomically write the list
head's ->next pointer.
hlist_add_behind() doesn't touch the hlist head's ->first pointer so
there is no reason to use WRITE_ONCE() in this case.
Co-developed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The migration scanner is a linear scan of a zone with a potentiall large
search space. Furthermore, many pageblocks are unusable such as those
filled with reserved pages or partially filled with pages that cannot
migrate. These still get scanned in the common case of allocating a THP
and the cost accumulates.
The patch uses a partial search of the free lists to locate a migration
source candidate that is marked as MOVABLE when allocating a THP. It
prefers picking a block with a larger number of free pages already on
the basis that there are fewer pages to migrate to free the entire
block. The lowest PFN found during searches is tracked as the basis of
the start for the linear search after the first search of the free list
fails. After the search, the free list is shuffled so that the next
search will not encounter the same page. If the search fails then the
subsequent searches will be shorter and the linear scanner is used.
If this search fails, or if the request is for a small or
unmovable/reclaimable allocation then the linear scanner is still used.
It is somewhat pointless to use the list search in those cases. Small
free pages must be used for the search and there is no guarantee that
movable pages are located within that block that are contiguous.
5.0.0-rc1 5.0.0-rc1
noboost-v3r10 findmig-v3r15
Amean fault-both-3 3771.41 ( 0.00%) 3390.40 ( 10.10%)
Amean fault-both-5 5409.05 ( 0.00%) 5082.28 ( 6.04%)
Amean fault-both-7 7040.74 ( 0.00%) 7012.51 ( 0.40%)
Amean fault-both-12 11887.35 ( 0.00%) 11346.63 ( 4.55%)
Amean fault-both-18 16718.19 ( 0.00%) 15324.19 ( 8.34%)
Amean fault-both-24 21157.19 ( 0.00%) 16088.50 * 23.96%*
Amean fault-both-30 21175.92 ( 0.00%) 18723.42 * 11.58%*
Amean fault-both-32 21339.03 ( 0.00%) 18612.01 * 12.78%*
5.0.0-rc1 5.0.0-rc1
noboost-v3r10 findmig-v3r15
Percentage huge-3 86.50 ( 0.00%) 89.83 ( 3.85%)
Percentage huge-5 92.52 ( 0.00%) 91.96 ( -0.61%)
Percentage huge-7 92.44 ( 0.00%) 92.85 ( 0.44%)
Percentage huge-12 92.98 ( 0.00%) 92.74 ( -0.25%)
Percentage huge-18 91.70 ( 0.00%) 91.71 ( 0.02%)
Percentage huge-24 91.59 ( 0.00%) 92.13 ( 0.60%)
Percentage huge-30 90.14 ( 0.00%) 93.79 ( 4.04%)
Percentage huge-32 90.03 ( 0.00%) 91.27 ( 1.37%)
This shows an improvement in allocation latencies with similar
allocation success rates. While not presented, there was a 31%
reduction in migration scanning and a 8% reduction on system CPU usage.
A 2-socket machine showed similar benefits.
[mgorman@techsingularity.net: several fixes]
Link: http://lkml.kernel.org/r/20190204120111.GL9565@techsingularity.net
[vbabka@suse.cz: migrate block that was found-fast, some optimisations]
Link: http://lkml.kernel.org/r/20190118175136.31341-10-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <Vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move all entries between @first and including @last before @head.
This is useful for LRU lists where a whole block of entries should be
moved to the end of the list.
Used as a band aid in TTM, but better placed in the common list headers.
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
First example of a layer splitting the list (rather than merely taking
individual packets off it).
Involves new list.h function, list_cut_before(), like list_cut_position()
but cuts on the other side of the given entry.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
