Track at which levels in the page-table entries were modified by
vmap/vunmap.
After the page-table has been modified, use that information do decide
whether the new arch_sync_kernel_mappings() needs to be called.
[akpm@linux-foundation.org: map_kernel_range_noflush() needs the arch_sync_kernel_mappings() call]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200515140023.25469-3-joro@8bytes.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: Get rid of vmalloc_sync_(un)mappings()", v3.
After the recent issue with vmalloc and tracing code[1] on x86 and a
long history of previous issues related to the vmalloc_sync_mappings()
interface, I thought the time has come to remove it. Please see [2],
[3], and [4] for some other issues in the past.
The patches add tracking of page-table directory changes to the vmalloc
and ioremap code. Depending on which page-table levels changes have
been made, a new per-arch function is called:
arch_sync_kernel_mappings().
On x86-64 with 4-level paging, this function will not be called more
than 64 times in a systems runtime (because vmalloc-space takes 64 PGD
entries which are only populated, but never cleared).
As a side effect this also allows to get rid of vmalloc faults on x86,
making it safe to touch vmalloc'ed memory in the page-fault handler.
Note that this potentially includes per-cpu memory.
This patch (of 7):
Add page-table allocation functions which will keep track of changed
directory entries. They are needed for new PGD, P4D, PUD, and PMD
entries and will be used in vmalloc and ioremap code to decide whether
any changes in the kernel mappings need to be synchronized between
page-tables in the system.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200515140023.25469-1-joro@8bytes.org
Link: http://lkml.kernel.org/r/20200515140023.25469-2-joro@8bytes.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Open code it in __bpf_map_area_alloc, which is the only caller. Also
clean up __bpf_map_area_alloc to have a single vmalloc call with slightly
different flags instead of the current two different calls.
For this to compile for the nommu case add a __vmalloc_node_range stub to
nommu.c.
[akpm@linux-foundation.org: fix nommu.c build]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200414131348.444715-27-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No need to export the very low-level __vmalloc_node_range when the test
module can use a slightly higher level variant.
[akpm@linux-foundation.org: add missing `node' arg]
[akpm@linux-foundation.org: fix riscv nommu build]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-26-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Just use __vmalloc_node instead which gets and extra argument. To be able
to to use __vmalloc_node in all caller make it available outside of
vmalloc and implement it in nommu.c.
[akpm@linux-foundation.org: fix nommu build]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200414131348.444715-25-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 25b2995a35 ("mm: remove MEMORY_DEVICE_PUBLIC support"),
the assignment to 'page' for pte_devmap case has been unnecessary.
Let's remove it.
[willy@infradead.org: changelog]
Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/1587349685-31712-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page table entry is passed in the 'val' argument to note_page(),
however this was previously an "unsigned long" which is fine on 64-bit
platforms. But for 32 bit x86 it is not always big enough to contain a
page table entry which may be 64 bits.
Change the type to u64 to ensure that it is always big enough.
[akpm@linux-foundation.org: fix riscv]
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200521152308.33096-3-steven.price@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Fix W+X debug feature on x86"
Jan alerted me[1] that the W+X detection debug feature was broken in x86
by my change[2] to switch x86 to use the generic ptdump infrastructure.
Fundamentally the approach of trying to move the calculation of
effective permissions into note_page() was broken because note_page() is
only called for 'leaf' entries and the effective permissions are passed
down via the internal nodes of the page tree. The solution I've taken
here is to create a new (optional) callback which is called for all
nodes of the page tree and therefore can calculate the effective
permissions.
Secondly on some configurations (32 bit with PAE) "unsigned long" is not
large enough to store the table entries. The fix here is simple - let's
just use a u64.
[1] https://lore.kernel.org/lkml/d573dc7e-e742-84de-473d-f971142fa319@suse.com/
[2] 2ae27137b2 ("x86: mm: convert dump_pagetables to use walk_page_range")
This patch (of 2):
By switching the x86 page table dump code to use the generic code the
effective permissions are no longer calculated correctly because the
note_page() function is only called for *leaf* entries. To calculate
the actual effective permissions it is necessary to observe the full
hierarchy of the page tree.
Introduce a new callback for ptdump which is called for every entry and
can therefore update the prot_levels array correctly. note_page() can
then simply access the appropriate element in the array.
[steven.price@arm.com: make the assignment conditional on val != 0]
Link: http://lkml.kernel.org/r/430c8ab4-e7cd-6933-dde6-087fac6db872@arm.com
Fixes: 2ae27137b2 ("x86: mm: convert dump_pagetables to use walk_page_range")
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200521152308.33096-1-steven.price@arm.com
Link: http://lkml.kernel.org/r/20200521152308.33096-2-steven.price@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a memory.swap.high knob, which can be used to protect the system
from SWAP exhaustion. The mechanism used for penalizing is similar to
memory.high penalty (sleep on return to user space).
That is not to say that the knob itself is equivalent to memory.high.
The objective is more to protect the system from potentially buggy tasks
consuming a lot of swap and impacting other tasks, or even bringing the
whole system to stand still with complete SWAP exhaustion. Hopefully
without the need to find per-task hard limits.
Slowing misbehaving tasks down gradually allows user space oom killers
or other protection mechanisms to react. oomd and earlyoom already do
killing based on swap exhaustion, and memory.swap.high protection will
help implement such userspace oom policies more reliably.
We can use one counter for number of pages allocated under pressure to
save struct task space and avoid two separate hierarchy walks on the hot
path. The exact overage is calculated on return to user space, anyway.
Take the new high limit into account when determining if swap is "full".
Borrowing the explanation from Johannes:
The idea behind "swap full" is that as long as the workload has plenty
of swap space available and it's not changing its memory contents, it
makes sense to generously hold on to copies of data in the swap device,
even after the swapin. A later reclaim cycle can drop the page without
any IO. Trading disk space for IO.
But the only two ways to reclaim a swap slot is when they're faulted
in and the references go away, or by scanning the virtual address space
like swapoff does - which is very expensive (one could argue it's too
expensive even for swapoff, it's often more practical to just reboot).
So at some point in the fill level, we have to start freeing up swap
slots on fault/swapin. Otherwise we could eventually run out of swap
slots while they're filled with copies of data that is also in RAM.
We don't want to OOM a workload because its available swap space is
filled with redundant cache.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Chris Down <chris@chrisdown.name>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200527195846.102707-5-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "memcg: Slow down swap allocation as the available space
gets depleted", v6.
Tejun describes the problem as follows:
When swap runs out, there's an abrupt change in system behavior - the
anonymous memory suddenly becomes unmanageable which readily breaks any
sort of memory isolation and can bring down the whole system. To avoid
that, oomd [1] monitors free swap space and triggers kills when it drops
below the specific threshold (e.g. 15%).
While this works, it's far from ideal:
- Depending on IO performance and total swap size, a given
headroom might not be enough or too much.
- oomd has to monitor swap depletion in addition to the usual
pressure metrics and it currently doesn't consider memory.swap.max.
Solve this by adapting parts of the approach that memory.high uses -
slow down allocation as the resource gets depleted turning the depletion
behavior from abrupt cliff one to gradual degradation observable through
memory pressure metric.
[1] https://github.com/facebookincubator/oomd
This patch (of 4):
Slice the memory overage calculation logic a little bit so we can reuse
it to apply a similar penalty to the swap. The logic which accesses the
memory-specific fields (use and high values) has to be taken out of
calculate_high_delay().
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200527195846.102707-1-kuba@kernel.org
Link: http://lkml.kernel.org/r/20200527195846.102707-2-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
One way to measure the efficiency of memory reclaim is to look at the
ratio (pgscan+pfrefill)/pgsteal. However at the moment these stats are
not updated consistently at the system level and the ratio of these are
not very meaningful. The pgsteal and pgscan are updated for only global
reclaim while pgrefill gets updated for global as well as cgroup
reclaim.
Please note that this difference is only for system level vmstats. The
cgroup stats returned by memory.stat are actually consistent. The
cgroup's pgsteal contains number of reclaimed pages for global as well
as cgroup reclaim. So, one way to get the system level stats is to get
these stats from root's memory.stat, so, expose memory.stat for the root
cgroup.
From Johannes Weiner:
There are subtle differences between /proc/vmstat and
memory.stat, and cgroup-aware code that wants to watch the full
hierarchy currently has to know about these intricacies and
translate semantics back and forth.
Generally having the fully recursive memory.stat at the root
level could help a broader range of usecases.
Why not fix the stats by including both the global and cgroup reclaim
activity instead of exposing root cgroup's memory.stat? The reason is
the benefit of having metrics exposing the activity that happens purely
due to machine capacity rather than localized activity that happens due
to the limits throughout the cgroup tree. Additionally there are
userspace tools like sysstat(sar) which reads these stats to inform
about the system level reclaim activity. So, we should not break such
use-cases.
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200508170630.94406-1-shakeelb@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There's a new workingset counter introduced in commit 1899ad18c6 ("mm:
workingset: tell cache transitions from workingset thrashing"). With
the help of this counter we can know the workingset is transitioning or
thrashing. To leverage the benifit of this counter to memcg, we should
introduce it into memory.stat. Then we could know the workingset of the
workload inside a memcg better.
Bellow is the verification of this new counter in memory.stat. Read a
file into the memory and then read it again to make these pages be
active. The size of this file is 1G. (memory.max is greater than file
size) The counters in memory.stat will be
inactive_file 0
active_file 1073639424
workingset_refault 0
workingset_activate 0
workingset_restore 0
workingset_nodereclaim 0
Trigger the memcg reclaim by setting a lower value to memory.high, and
then some pages will be demoted into inactive list, and then some pages
in the inactive list will be evicted into the storage.
inactive_file 498094080
active_file 310063104
workingset_refault 0
workingset_activate 0
workingset_restore 0
workingset_nodereclaim 0
Then recover the memory.high and read the file into memory again. As a
result of it, the transitioning will occur. Bellow is the result of
this transitioning,
inactive_file 498094080
active_file 575397888
workingset_refault 64746
workingset_activate 64746
workingset_restore 64746
workingset_nodereclaim 0
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Link: http://lkml.kernel.org/r/20200504153522.11553-1-laoar.shao@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
