- 08 Jun, 2017 7 commits
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Christoffer Dall authored
We check if other in-kernel devices have already been connected to the GIC for a particular interrupt line when possible. For the PMU, we can do this whenever setting the PMU interrupt number from userspace. For the timers, we have to wait until we try to enable the timer, because we have a concept of default IRQ numbers that userspace shouldn't have to work around in the initialization phase. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
Having multiple devices being able to signal the same interrupt line is very confusing and almost certainly guarantees a configuration error. Therefore, introduce a very simple allocator which allows a device to claim an interrupt line from the vgic for a given VM. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Acked-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
First we define an ABI using the vcpu devices that lets userspace set the interrupt numbers for the various timers on both the 32-bit and 64-bit KVM/ARM implementations. Second, we add the definitions for the groups and attributes introduced by the above ABI. (We add the PMU define on the 32-bit side as well for symmetry and it may get used some day.) Third, we set up the arch-specific vcpu device operation handlers to call into the timer code for anything related to the KVM_ARM_VCPU_TIMER_CTRL group. Fourth, we implement support for getting and setting the timer interrupt numbers using the above defined ABI in the arch timer code. Fifth, we introduce error checking upon enabling the arch timer (which is called when first running a VCPU) to check that all VCPUs are configured to use the same PPI for the timer (as mandated by the architecture) and that the virtual and physical timers are not configured to use the same IRQ number. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
We currently initialize the arch timer IRQ numbers from the reset code, presumably because we once intended to model multiple CPU or SoC types from within the kernel and have hard-coded reset values in the reset code. As we are moving towards userspace being in charge of more fine-grained CPU emulation and stitching together the pieces needed to emulate a particular type of CPU, we should no longer have a tight coupling between resetting a VCPU and setting IRQ numbers. Therefore, move the logic to define and use the default IRQ numbers to the timer code and set the IRQ number immediately when creating the VCPU. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
We are about to need this define in the arch timer code as well so move it to a common location. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Acked-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
As we are about to support VCPU attributes to set the timer IRQ numbers in guest.c, move the static inlines for the VCPU attributes handlers from the header file to guest.c. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Acked-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
Since we got support for devices in userspace which allows reporting the PMU overflow output status to userspace, we should actually allow creating the PMU on systems without an in-kernel irqchip, which in turn requires us to slightly clarify error codes for the ABI and move things around for the initialization phase. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com>
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- 04 Jun, 2017 12 commits
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Andrew Jones authored
The timer work is only scheduled for a VCPU when that VCPU is blocked. This means we only need to wake it up, not kick (IPI) it. While calling kvm_vcpu_kick() would just do the wake up, and not kick, anyway, let's change this to avoid request-less vcpu kicks, as they're generally not a good idea (see "Request-less VCPU Kicks" in Documentation/virtual/kvm/vcpu-requests.rst) Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
Refactor PMU overflow handling in order to remove the request-less vcpu kick. Now, since kvm_vgic_inject_irq() uses vcpu requests, there should be no chance that a kick sent at just the wrong time (between the VCPU's call to kvm_pmu_flush_hwstate() and before it enters guest mode) results in a failure for the guest to see updated GIC state until its next exit some time later for some other reason. Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
Don't use request-less VCPU kicks when injecting IRQs, as a VCPU kick meant to trigger the interrupt injection could be sent while the VCPU is outside guest mode, which means no IPI is sent, and after it has called kvm_vgic_flush_hwstate(), meaning it won't see the updated GIC state until its next exit some time later for some other reason. The receiving VCPU only needs to check this request in VCPU RUN to handle it. By checking it, if it's pending, a memory barrier will be issued that ensures all state is visible. See "Ensuring Requests Are Seen" of Documentation/virtual/kvm/vcpu-requests.rst Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
A request called EXIT is too generic. All requests are meant to cause exits, but different requests have different flags. Let's not make it difficult to decide if the EXIT request is correct for some case by just always providing unique requests for each case. This patch changes EXIT to SLEEP, because that's what the request is asking the VCPU to do. Signed-off-by:
Andrew Jones <drjones@redhat.com> Acked-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
We can make a small optimization by not checking the state of the power_off field on each run. This is done by treating power_off like pause, only checking it when we get the EXIT VCPU request. When a VCPU powers off another VCPU the EXIT request is already made, so we just need to make sure the request is also made on self power off. kvm_vcpu_kick() isn't necessary for these cases, as the VCPU would just be kicking itself, but we add it anyway as a self kick doesn't cost much, and it makes the code more future-proof. Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
System shutdown is currently using request-less VCPU kicks. This leaves open a tiny race window, as it doesn't ensure the state change to power_off is seen by a VCPU just about to enter guest mode. VCPU requests, OTOH, are guaranteed to be seen (see "Ensuring Requests Are Seen" of Documentation/virtual/kvm/vcpu-requests.rst) This patch applies the EXIT request used by pause to power_off, fixing the race. Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
The current use of KVM_REQ_VCPU_EXIT for pause is fine. Even the requester clearing the request is OK, as this is the special case where the sole requesting thread and receiving VCPU are executing synchronously (see "Clearing Requests" in Documentation/virtual/kvm/vcpu-requests.rst) However, that's about to change, so let's ensure only the receiving VCPU clears the request. Additionally, by guaranteeing KVM_REQ_VCPU_EXIT is always set when pause is, we can avoid checking pause directly in VCPU RUN. Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
arm/arm64 already has one VCPU request used when setting pause, but it doesn't properly check requests in VCPU RUN. Check it and also make sure we set vcpu->mode at the appropriate time (before the check) and with the appropriate barriers. See Documentation/virtual/kvm/vcpu-requests.rst. Also make sure we don't leave any vcpu requests we don't intend to handle later set in the request bitmap. If we don't clear them, then kvm_request_pending() may return true when it shouldn't. Using VCPU requests properly fixes a small race where pause could get set just as a VCPU was entering guest mode. Signed-off-by:
Andrew Jones <drjones@redhat.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
Signed-off-by:
Andrew Jones <drjones@redhat.com> Acked-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Radim Krčmář authored
A first step in vcpu->requests encapsulation. Additionally, we now use READ_ONCE() when accessing vcpu->requests, which ensures we always load vcpu->requests when it's accessed. This is important as other threads can change it any time. Also, READ_ONCE() documents that vcpu->requests is used with other threads, likely requiring memory barriers, which it does. Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com> [ Documented the new use of READ_ONCE() and converted another check in arch/mips/kvm/vz.c ] Signed-off-by:
Andrew Jones <drjones@redhat.com> Acked-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Andrew Jones authored
Marc Zyngier suggested that we define the arch specific VCPU request base, rather than requiring each arch to remember to start from 8. That suggestion, along with Radim Krcmar's recent VCPU request flag addition, snowballed into defining something of an arch VCPU request defining API. No functional change. (Looks like x86 is running out of arch VCPU request bits. Maybe someday we'll need to extend to 64.) Signed-off-by:
Andrew Jones <drjones@redhat.com> Acked-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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Christoffer Dall authored
We recently rewrote the sactive and cactive handlers to take the kvm lock for guest accesses to these registers. However, when accessed from userspace this lock is already held. Unfortunately we forgot to change the private accessors for GICv3, because these are redistributor registers and not distributor registers. Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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- 23 May, 2017 3 commits
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Christoffer Dall authored
We don't need to stop a specific VCPU when changing the active state, because private IRQs can only be modified by a running VCPU for the VCPU itself and it is therefore already stopped. However, it is also possible for two VCPUs to be modifying the active state of SPIs at the same time, which can cause the thread being stuck in the loop that checks other VCPU threads for a potentially very long time, or to modify the active state of a running VCPU. Fix this by serializing all accesses to setting and clearing the active state of interrupts using the KVM mutex. Reported-by:
Andrew Jones <drjones@redhat.com> Signed-off-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
Factor out the core register modifier functionality from the entry points from the register description table, and only call the prepare/finish functions from the guest path, not the uaccess path. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com>
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Christoffer Dall authored
We are about to differentiate between writes from a VCPU and from userspace to the GIC's GICD_ISACTIVER and GICD_ICACTIVER registers due to different synchronization requirements. Expand the macro to define a register description for the GIC to take uaccess functions as well. Signed-off-by:
Christoffer Dall <cdall@linaro.org> Acked-by:
Marc Zyngier <marc.zyngier@arm.com>
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- 16 May, 2017 2 commits
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James Morse authored
When KVM panics, it hurridly restores the host context and parachutes into the host's panic() code. At some point panic() touches the physical timer/counter. Unless we are an arm64 system with VHE, this traps back to EL2. If we're lucky, we panic again. Add a __timer_save_state() call to KVMs hyp_panic() path, this saves the guest registers and disables the traps for the host. Fixes: 53fd5b64 ("arm64: KVM: Add panic handling") Signed-off-by:
James Morse <james.morse@arm.com> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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James Morse authored
When KVM panics, it hurridly restores the host context and parachutes into the host's panic() code. This looks like it was copied from arm64, the 32bit KVM panic code needs to restore the host's banked registers too. At some point panic() touches the physical timer/counter, this will trap back to HYP. If we're lucky, we panic again. Add a __timer_save_state() call to KVMs hyp_panic() path, this saves the guest registers and disables the traps for the host. Fixes: c36b6db5 ("ARM: KVM: Add panic handling code") Signed-off-by:
James Morse <james.morse@arm.com> Reviewed-by:
Marc Zyngier <marc.zyngier@arm.com> Reviewed-by:
Christoffer Dall <cdall@linaro.org> Signed-off-by:
Christoffer Dall <cdall@linaro.org>
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- 13 May, 2017 5 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/dtor/inputLinus Torvalds authored
Pull some more input subsystem updates from Dmitry Torokhov: "An updated xpad driver with a few more recognized device IDs, and a new psxpad-spi driver, allowing connecting Playstation 1 and 2 joypads via SPI bus" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: cros_ec_keyb - remove extraneous 'const' Input: add support for PlayStation 1/2 joypads connected via SPI Input: xpad - add USB IDs for Mad Catz Brawlstick and Razer Sabertooth Input: xpad - sync supported devices with xboxdrv Input: xpad - sort supported devices by USB ID
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git://git.infradead.org/linux-ubifsLinus Torvalds authored
Pull UBI/UBIFS updates from Richard Weinberger: - new config option CONFIG_UBIFS_FS_SECURITY - minor improvements - random fixes * tag 'upstream-4.12-rc1' of git://git.infradead.org/linux-ubifs: ubi: Add debugfs file for tracking PEB state ubifs: Fix a typo in comment of ioctl2ubifs & ubifs2ioctl ubifs: Remove unnecessary assignment ubifs: Fix cut and paste error on sb type comparisons ubi: fastmap: Fix slab corruption ubifs: Add CONFIG_UBIFS_FS_SECURITY to disable/enable security labels ubi: Make mtd parameter readable ubi: Fix section mismatch
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git://git.kernel.org/pub/scm/linux/kernel/git/rw/umlLinus Torvalds authored
Pull UML fixes from Richard Weinberger: "No new stuff, just fixes" * 'for-linus-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: Add missing NR_CPUS include um: Fix to call read_initrd after init_bootmem um: Include kbuild.h instead of duplicating its macros um: Fix PTRACE_POKEUSER on x86_64 um: Set number of CPUs um: Fix _print_addr()
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Linus Torvalds authored
Merge misc fixes from Andrew Morton: "15 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm, docs: update memory.stat description with workingset* entries mm: vmscan: scan until it finds eligible pages mm, thp: copying user pages must schedule on collapse dax: fix PMD data corruption when fault races with write dax: fix data corruption when fault races with write ext4: return to starting transaction in ext4_dax_huge_fault() mm: fix data corruption due to stale mmap reads dax: prevent invalidation of mapped DAX entries Tigran has moved mm, vmalloc: fix vmalloc users tracking properly mm/khugepaged: add missed tracepoint for collapse_huge_page_swapin gcov: support GCC 7.1 mm, vmstat: Remove spurious WARN() during zoneinfo print time: delete current_fs_time() hwpoison, memcg: forcibly uncharge LRU pages
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- 12 May, 2017 11 commits
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Roman Gushchin authored
Commit 4b4cea91691d ("mm: vmscan: fix IO/refault regression in cache workingset transition") introduced three new entries in memory stat file: - workingset_refault - workingset_activate - workingset_nodereclaim This commit adds a corresponding description to the cgroup v2 docs. Link: http://lkml.kernel.org/r/1494530293-31236-1-git-send-email-guro@fb.comSigned-off-by:
Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Minchan Kim authored
Although there are a ton of free swap and anonymous LRU page in elgible zones, OOM happened. balloon invoked oom-killer: gfp_mask=0x17080c0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_NOTRACK), nodemask=(null), order=0, oom_score_adj=0 CPU: 7 PID: 1138 Comm: balloon Not tainted 4.11.0-rc6-mm1-zram-00289-ge228d67e9677-dirty #17 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: oom_kill_process+0x21d/0x3f0 out_of_memory+0xd8/0x390 __alloc_pages_slowpath+0xbc1/0xc50 __alloc_pages_nodemask+0x1a5/0x1c0 pte_alloc_one+0x20/0x50 __pte_alloc+0x1e/0x110 __handle_mm_fault+0x919/0x960 handle_mm_fault+0x77/0x120 __do_page_fault+0x27a/0x550 trace_do_page_fault+0x43/0x150 do_async_page_fault+0x2c/0x90 async_page_fault+0x28/0x30 Mem-Info: active_anon:424716 inactive_anon:65314 isolated_anon:0 active_file:52 inactive_file:46 isolated_file:0 unevictable:0 dirty:27 writeback:0 unstable:0 slab_reclaimable:3967 slab_unreclaimable:4125 mapped:133 shmem:43 pagetables:1674 bounce:0 free:4637 free_pcp:225 free_cma:0 Node 0 active_anon:1698864kB inactive_anon:261256kB active_file:208kB inactive_file:184kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:532kB dirty:108kB writeback:0kB shmem:172kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no DMA free:7316kB min:32kB low:44kB high:56kB active_anon:8064kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:464kB slab_unreclaimable:40kB kernel_stack:0kB pagetables:24kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 992 992 1952 DMA32 free:9088kB min:2048kB low:3064kB high:4080kB active_anon:952176kB inactive_anon:0kB active_file:36kB inactive_file:0kB unevictable:0kB writepending:88kB present:1032192kB managed:1019388kB mlocked:0kB slab_reclaimable:13532kB slab_unreclaimable:16460kB kernel_stack:3552kB pagetables:6672kB bounce:0kB free_pcp:56kB local_pcp:24kB free_cma:0kB lowmem_reserve[]: 0 0 0 959 Movable free:3644kB min:1980kB low:2960kB high:3940kB active_anon:738560kB inactive_anon:261340kB active_file:188kB inactive_file:640kB unevictable:0kB writepending:20kB present:1048444kB managed:1010816kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:832kB local_pcp:60kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 DMA: 1*4kB (E) 0*8kB 18*16kB (E) 10*32kB (E) 10*64kB (E) 9*128kB (ME) 8*256kB (E) 2*512kB (E) 2*1024kB (E) 0*2048kB 0*4096kB = 7524kB DMA32: 417*4kB (UMEH) 181*8kB (UMEH) 68*16kB (UMEH) 48*32kB (UMEH) 14*64kB (MH) 3*128kB (M) 1*256kB (H) 1*512kB (M) 2*1024kB (M) 0*2048kB 0*4096kB = 9836kB Movable: 1*4kB (M) 1*8kB (M) 1*16kB (M) 1*32kB (M) 0*64kB 1*128kB (M) 2*256kB (M) 4*512kB (M) 1*1024kB (M) 0*2048kB 0*4096kB = 3772kB 378 total pagecache pages 17 pages in swap cache Swap cache stats: add 17325, delete 17302, find 0/27 Free swap = 978940kB Total swap = 1048572kB 524157 pages RAM 0 pages HighMem/MovableOnly 12629 pages reserved 0 pages cma reserved 0 pages hwpoisoned [ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name [ 433] 0 433 4904 5 14 3 82 0 upstart-udev-br [ 438] 0 438 12371 5 27 3 191 -1000 systemd-udevd With investigation, skipping page of isolate_lru_pages makes reclaim void because it returns zero nr_taken easily so LRU shrinking is effectively nothing and just increases priority aggressively. Finally, OOM happens. The problem is that get_scan_count determines nr_to_scan with eligible zones so although priority drops to zero, it couldn't reclaim any pages if the LRU contains mostly ineligible pages. get_scan_count: size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx); size = size >> sc->priority; Assumes sc->priority is 0 and LRU list is as follows. N-N-N-N-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H (Ie, small eligible pages are in the head of LRU but others are almost ineligible pages) In that case, size becomes 4 so VM want to scan 4 pages but 4 pages from tail of the LRU are not eligible pages. If get_scan_count counts skipped pages, it doesn't reclaim any pages remained after scanning 4 pages so it ends up OOM happening. This patch makes isolate_lru_pages try to scan pages until it encounters eligible zones's pages. [akpm@linux-foundation.org: clean up mind-bending `for' statement. Tweak comment text] Fixes: 3db65812 ("Revert "mm, vmscan: account for skipped pages as a partial scan"") Link: http://lkml.kernel.org/r/1494457232-27401-1-git-send-email-minchan@kernel.orgSigned-off-by:
Minchan Kim <minchan@kernel.org> Acked-by:
Michal Hocko <mhocko@suse.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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David Rientjes authored
We have encountered need_resched warnings in __collapse_huge_page_copy() while doing {clear,copy}_user_highpage() over HPAGE_PMD_NR source pages. mm->mmap_sem is held for write, but the iteration is well bounded. Reschedule as needed. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705101426380.109808@chino.kir.corp.google.comSigned-off-by:
David Rientjes <rientjes@google.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Ross Zwisler authored
This is based on a patch from Jan Kara that fixed the equivalent race in the DAX PTE fault path. Currently DAX PMD read fault can race with write(2) in the following way: CPU1 - write(2) CPU2 - read fault dax_iomap_pmd_fault() ->iomap_begin() - sees hole dax_iomap_rw() iomap_apply() ->iomap_begin - allocates blocks dax_iomap_actor() invalidate_inode_pages2_range() - there's nothing to invalidate grab_mapping_entry() - we add huge zero page to the radix tree and map it to page tables The result is that hole page is mapped into page tables (and thus zeros are seen in mmap) while file has data written in that place. Fix the problem by locking exception entry before mapping blocks for the fault. That way we are sure invalidate_inode_pages2_range() call for racing write will either block on entry lock waiting for the fault to finish (and unmap stale page tables after that) or read fault will see already allocated blocks by write(2). Fixes: 9f141d6e ("dax: Call ->iomap_begin without entry lock during dax fault") Link: http://lkml.kernel.org/r/20170510172700.18991-1-ross.zwisler@linux.intel.comSigned-off-by:
Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Jan Kara authored
Currently DAX read fault can race with write(2) in the following way: CPU1 - write(2) CPU2 - read fault dax_iomap_pte_fault() ->iomap_begin() - sees hole dax_iomap_rw() iomap_apply() ->iomap_begin - allocates blocks dax_iomap_actor() invalidate_inode_pages2_range() - there's nothing to invalidate grab_mapping_entry() - we add zero page in the radix tree and map it to page tables The result is that hole page is mapped into page tables (and thus zeros are seen in mmap) while file has data written in that place. Fix the problem by locking exception entry before mapping blocks for the fault. That way we are sure invalidate_inode_pages2_range() call for racing write will either block on entry lock waiting for the fault to finish (and unmap stale page tables after that) or read fault will see already allocated blocks by write(2). Fixes: 9f141d6e Link: http://lkml.kernel.org/r/20170510085419.27601-5-jack@suse.czSigned-off-by:
Jan Kara <jack@suse.cz> Reviewed-by:
Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Jan Kara authored
DAX will return to locking exceptional entry before mapping blocks for a page fault to fix possible races with concurrent writes. To avoid lock inversion between exceptional entry lock and transaction start, start the transaction already in ext4_dax_huge_fault(). Fixes: 9f141d6e Link: http://lkml.kernel.org/r/20170510085419.27601-4-jack@suse.czSigned-off-by:
Jan Kara <jack@suse.cz> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Jan Kara authored
Currently, we didn't invalidate page tables during invalidate_inode_pages2() for DAX. That could result in e.g. 2MiB zero page being mapped into page tables while there were already underlying blocks allocated and thus data seen through mmap were different from data seen by read(2). The following sequence reproduces the problem: - open an mmap over a 2MiB hole - read from a 2MiB hole, faulting in a 2MiB zero page - write to the hole with write(3p). The write succeeds but we incorrectly leave the 2MiB zero page mapping intact. - via the mmap, read the data that was just written. Since the zero page mapping is still intact we read back zeroes instead of the new data. Fix the problem by unconditionally calling invalidate_inode_pages2_range() in dax_iomap_actor() for new block allocations and by properly invalidating page tables in invalidate_inode_pages2_range() for DAX mappings. Fixes: c6dcf52c Link: http://lkml.kernel.org/r/20170510085419.27601-3-jack@suse.czSigned-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Ross Zwisler authored
Patch series "mm,dax: Fix data corruption due to mmap inconsistency", v4. This series fixes data corruption that can happen for DAX mounts when page faults race with write(2) and as a result page tables get out of sync with block mappings in the filesystem and thus data seen through mmap is different from data seen through read(2). The series passes testing with t_mmap_stale test program from Ross and also other mmap related tests on DAX filesystem. This patch (of 4): dax_invalidate_mapping_entry() currently removes DAX exceptional entries only if they are clean and unlocked. This is done via: invalidate_mapping_pages() invalidate_exceptional_entry() dax_invalidate_mapping_entry() However, for page cache pages removed in invalidate_mapping_pages() there is an additional criteria which is that the page must not be mapped. This is noted in the comments above invalidate_mapping_pages() and is checked in invalidate_inode_page(). For DAX entries this means that we can can end up in a situation where a DAX exceptional entry, either a huge zero page or a regular DAX entry, could end up mapped but without an associated radix tree entry. This is inconsistent with the rest of the DAX code and with what happens in the page cache case. We aren't able to unmap the DAX exceptional entry because according to its comments invalidate_mapping_pages() isn't allowed to block, and unmap_mapping_range() takes a write lock on the mapping->i_mmap_rwsem. Since we essentially never have unmapped DAX entries to evict from the radix tree, just remove dax_invalidate_mapping_entry(). Fixes: c6dcf52c ("mm: Invalidate DAX radix tree entries only if appropriate") Link: http://lkml.kernel.org/r/20170510085419.27601-2-jack@suse.czSigned-off-by:
Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by:
Jan Kara <jack@suse.cz> Reported-by:
Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> [4.10+] Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Andrew Morton authored
Cc: Tigran Aivazian <aivazian.tigran@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Michal Hocko authored
Commit 1f5307b1 ("mm, vmalloc: properly track vmalloc users") has pulled asm/pgtable.h include dependency to linux/vmalloc.h and that turned out to be a bad idea for some architectures. E.g. m68k fails with In file included from arch/m68k/include/asm/pgtable_mm.h:145:0, from arch/m68k/include/asm/pgtable.h:4, from include/linux/vmalloc.h:9, from arch/m68k/kernel/module.c:9: arch/m68k/include/asm/mcf_pgtable.h: In function 'nocache_page': >> arch/m68k/include/asm/mcf_pgtable.h:339:43: error: 'init_mm' undeclared (first use in this function) #define pgd_offset_k(address) pgd_offset(&init_mm, address) as spotted by kernel build bot. nios2 fails for other reason In file included from include/asm-generic/io.h:767:0, from arch/nios2/include/asm/io.h:61, from include/linux/io.h:25, from arch/nios2/include/asm/pgtable.h:18, from include/linux/mm.h:70, from include/linux/pid_namespace.h:6, from include/linux/ptrace.h:9, from arch/nios2/include/uapi/asm/elf.h:23, from arch/nios2/include/asm/elf.h:22, from include/linux/elf.h:4, from include/linux/module.h:15, from init/main.c:16: include/linux/vmalloc.h: In function '__vmalloc_node_flags': include/linux/vmalloc.h:99:40: error: 'PAGE_KERNEL' undeclared (first use in this function); did you mean 'GFP_KERNEL'? which is due to the newly added #include <asm/pgtable.h>, which on nios2 includes <linux/io.h> and thus <asm/io.h> and <asm-generic/io.h> which again includes <linux/vmalloc.h>. Tweaking that around just turns out a bigger headache than necessary. This patch reverts 1f5307b1 and reimplements the original fix in a different way. __vmalloc_node_flags can stay static inline which will cover vmalloc* functions. We only have one external user (kvmalloc_node) and we can export __vmalloc_node_flags_caller and provide the caller directly. This is much simpler and it doesn't really need any games with header files. [akpm@linux-foundation.org: coding-style fixes] [mhocko@kernel.org: revert old comment] Link: http://lkml.kernel.org/r/20170509211054.GB16325@dhcp22.suse.cz Fixes: 1f5307b1 ("mm, vmalloc: properly track vmalloc users") Link: http://lkml.kernel.org/r/20170509153702.GR6481@dhcp22.suse.czSigned-off-by:
Michal Hocko <mhocko@suse.com> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
One return case of `__collapse_huge_page_swapin()` does not invoke tracepoint while every other return case does. This commit adds a tracepoint invocation for the case. Link: http://lkml.kernel.org/r/20170507101813.30187-1-sj38.park@gmail.comSigned-off-by:
SeongJae Park <sj38.park@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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