- Dec 17, 2018
-
-
Heiko Stuebner authored
The tmp108 does have an alert output that can be used as interrupt source and can of course also be used as part of a thermal sensor setup for things like thermal-based cpu frequencies, so document the necessary properties. Signed-off-by:
Heiko Stuebner <heiko.stuebner@bq.com> Reviewed-by:
Rob Herring <robh@kernel.org> Signed-off-by:
Guenter Roeck <linux@roeck-us.net>
-
Nicolin Chen authored
According to the code right before the removed line, data->kind should be either from DT or from id pointer. So there shouldn't be an additional overwriting after the if-else statement. So this patch just removes the overwriting line. Signed-off-by:
Nicolin Chen <nicoleotsuka@gmail.com> Signed-off-by:
-
Nicolin Chen authored
If all three channels are disabled via in[123]_enable ABI, the driver could suspend the chip for power saving purpose. So this patch adds the PM runtime support in order to gain more power control than system suspend and resume use case. For PM runtime, there are a few related changes happening: 1) Added a new pm_dev device pointer for all the PM runtime callbacks. This is because hwmon core registers a child device for each hwmon driver and passes it back to each driver. So there might be a mismatch between two device pointers in the driver if mixing using them. 2) Added a check in ina3221_is_enabled() to make sure that the chip is resumed. 3) Bypassed the unchanged status in ina3221_write_enable() in order to keep the PM runtime refcount being matched. 4) Removed the reset routine in the probe() by calling the resume() via pm_runtime_get_sync() instead, as they're similar. It's also necessary to do so to match initial PM refcount with the number of enabled channels. Signed-off-by:
-
Nicolin Chen authored
The data might need some time to get ready after channel enabling, although the data register is always readable. The CVRF bit is to indicate that data conversion is finished, so polling the CVRF bit before data reading could ensure the result being valid. An alternative way could be to wait for expected time between the channel enabling and the data reading. And this could avoid extra I2C communications. However, INA3221 seemly takes longer time than what's stated in the datasheet. Test results show that sometimes it couldn't finish data conversion in time. So this patch plays safe by adding a CVRF polling to make sure the data register is updated with the new data. Signed-off-by:
-
Nicolin Chen authored
This change adds a mutex to serialize accesses of sysfs attributes. This is required when polling CVRF bit of the MASK/ENABLE register because this bit is cleared on a read of this MASK/ENABLE register or a write to CONFIG register, which means that this bit might be accidentally cleared by reading other fields like alert flags. So this patch adds a mutex lock to protect the write() and read() callbacks. The read_string() callback won't need the lock since it just returns the label without touching any hardware register. Signed-off-by:
-
Nicolin Chen authored
There is nothing critically wrong to read these two attributes without having a is_enabled() check at this point. But reading the MASK_ENABLE register would clear the CVRF bit according to the datasheet. So it'd be safer to fence for disabled channels in order to add pm runtime feature. Signed-off-by:
-
Eddie James authored
The OCC provides a variety of additional information about the state of the host processor, such as throttling, error conditions, and the number of OCCs detected in the system. This information is essential to service processor applications such as fan control and host management. Therefore, export this data in the form of sysfs attributes attached to the platform device (to which the hwmon device is also attached). Signed-off-by:
Eddie James <eajames@linux.ibm.com> Signed-off-by:
-
Eddie James authored
Setup the sensor attributes for every OCC sensor found by the first poll response. Register the attributes with hwmon. Signed-off-by:
-
Eddie James authored
Add structures to define all sensor types and versions. Add sysfs show and store functions for each sensor type. Add a method to construct the "set user power cap" command and send it to the OCC. Add rate limit to polling the OCC (in case user-space reads our hwmon entries rapidly). Signed-off-by:
-
Eddie James authored
Add method to parse the response from the OCC poll command. This only needs to be done during probe(), since the OCC shouldn't change the number or format of sensors while it's running. The parsed response allows quick access to sensor data, as well as information on the number and version of sensors, which we need to instantiate hwmon attributes. Signed-off-by:
-
Eddie James authored
For the P8 OCC, add the procedure to send a command to the OCC over I2C bus. This involves writing the OCC command registers with serial communication operations (SCOMs) interpreted by the I2C slave. For the P9 OCC, add a procedure to use the OCC in-kernel API to send a command to the OCC through the SBE. Signed-off-by:
-
Eddie James authored
The OCC is a device embedded on a POWER processor that collects and aggregates sensor data from the processor and system. The OCC can provide the raw sensor data as well as perform thermal and power management on the system. This driver provides a hwmon interface to the OCC from a service processor (e.g. a BMC). The driver supports both POWER8 and POWER9 OCCs. Communications with the POWER8 OCC are established over standard I2C bus. The driver communicates with the POWER9 OCC through the FSI-based OCC driver, which handles the lower-level communication details. This patch lays out the structure of the OCC hwmon driver. There are two platform drivers, one each for P8 and P9 OCCs. These are probed through the I2C tree and the FSI-based OCC driver, respectively. The patch also defines the first common structures and methods between the two OCC versions. Signed-off-by:
-
- Dec 03, 2018
-
-
Eddie James authored
Document the bindings for I2C-based OCC hwmon device. Signed-off-by:
-
Eddie James authored
Document the hwmon interface for the OCC. Signed-off-by:
-
Eddie James authored
The OCC is a device embedded on a POWER processor that collects and aggregates sensor data from the processor and system. The OCC can provide the raw sensor data as well as perform thermal and power management on the system. This driver provides an atomic communications channel between a service processor (e.g. a BMC) and the OCC. The driver is dependent on the FSI SBEFIFO driver to get hardware access through the SBE to the OCC SRAM. Commands are issued to the SBE to send or fetch data to the SRAM. Signed-off-by:
Andrew Jeffery <andrew@aj.id.au> Signed-off-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
Joel Stanley <joel@jms.id.au> Signed-off-by:
-
Eddie James authored
Document the bindings for the FSI-attached POWER9 On-Chip Controller. Signed-off-by:
-
Chris Packham authored
As per the usual standard with hwmon drivers the mapping to sysfs entries follows the register map of the device e.g. in0_input corresponds to the register 0x20, in1_input corresponds to 0x21 etc. Hardware designers tend to work with input pins instead of registers which is where things start to get confusing. A hardware designer might say "the 1.5V rail is connected to the VCCP pin" leaving the software designer none the wiser as to which of the sysfs entries should be associated with the label "1.5V". Try to bridge the gap by documenting the mapping of sysfs entries to the corresponding pins. This should allow someone to create a configuration file or other mapping without needing to dive into the code and ADT datasheets. Signed-off-by:
Chris Packham <chris.packham@alliedtelesis.co.nz> Signed-off-by:
-
Rasmus Villemoes authored
struct attribute::name which this local variable name is eventually assigned to is "const char*", and so is the template parameter. We might as well preserve the constness all the way through. Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
-
Kun Yi authored
The ADM series of hotswap controllers support extending the current measurement range by using a sensing resistor value other than the typical 1 mOhm. For example, using a 0.5 mOhm sensing resistor doubles the maximal current can be measured. Current driver assumes a shunt resistor value of 1 mOhm in calculation, meaning for other resistor values, hwmon will report scaled current/power measurements. This patch parses device tree parameter "shunt-resistor-micro-ohms", if there is one. Signed-off-by:
Kun Yi <kunyi@google.com> Signed-off-by:
-
Kun Yi authored
adm127x are hot-swap controllers that allow a circuit board to be removed from or inserted into a live backplane. This patch adds the device tree bindings documentation. Signed-off-by:
-
Linus Torvalds authored
-
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-socLinus Torvalds authored
Pull ARM SoC fixes from Olof Johansson: "Volume is a little higher than usual due to a set of gpio fixes for Davinci platforms that's been around a while, still seemed appropriate to not hold off until next merge window. Besides that it's the usual mix of minor fixes, mostly corrections of small stuff in device trees. Major stability-related one is the removal of a regulator from DT on Rock960, since DVFS caused undervoltage. I expect it'll be restored once they figure out the underlying issue" * tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (28 commits) MAINTAINERS: Remove unused Qualcomm SoC mailing list ARM: davinci: dm644x: set the GPIO base to 0 ARM: davinci: da830: set the GPIO base to 0 ARM: davinci: dm355: set the GPIO base to 0 ARM: davinci: dm646x: set the GPIO base to 0 ARM: davinci: dm365: set the GPIO base to 0 ARM: davinci: da850: set the GPIO base to 0 gpio: davinci: restore a way to manually specify the GPIO base ARM: davinci: dm644x: define gpio interrupts as separate resources ARM: davinci: dm355: define gpio interrupts as separate resources ARM: davinci: dm646x: define gpio interrupts as separate resources ARM: davinci: dm365: define gpio interrupts as separate resources ARM: davinci: da8xx: define gpio interrupts as separate resources ARM: dts: at91: sama5d2: use the divided clock for SMC ARM: dts: imx51-zii-rdu1: Remove EEPROM node ARM: dts: rockchip: Remove @0 from the veyron memory node arm64: dts: rockchip: Fix PCIe reset polarity for rk3399-puma-haikou. arm64: dts: qcom: msm8998: Reserve gpio ranges on MTP arm64: dts: sdm845-mtp: Reserve reserved gpios arm64: dts: ti: k3-am654: Fix wakeup_uart reg address ...
-
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tipLinus Torvalds authored
Pull xen fixes from Juergen Gross: - A revert of a previous commit as it is no longer necessary and has shown to cause problems in some memory hotplug cases. - Some small fixes and a minor cleanup. - A patch for adding better diagnostic data in a very rare failure case. * tag 'for-linus-4.20a-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: pvcalls-front: fixes incorrect error handling Revert "xen/balloon: Mark unallocated host memory as UNUSABLE" xen: xlate_mmu: add missing header to fix 'W=1' warning xen/x86: add diagnostic printout to xen_mc_flush() in case of error x86/xen: cleanup includes in arch/x86/xen/spinlock.c
-
git://git.infradead.org/users/vkoul/slave-dmaLinus Torvalds authored
Pull dmaengine fixes from Vinod Koul: "This contains two fixes to at_hdmac which fixes long standing bus reported recently on serial transfers causing memory leak. These fixes were done by Richard Genoud" * tag 'dmaengine-fix-4.20-rc5' of git://git.infradead.org/users/vkoul/slave-dma: dmaengine: at_hdmac: fix module unloading dmaengine: at_hdmac: fix memory leak in at_dma_xlate()
-
- Dec 02, 2018
-
-
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull STIBP fallout fixes from Thomas Gleixner: "The performance destruction department finally got it's act together and came up with a cure for the STIPB regression: - Provide a command line option to control the spectre v2 user space mitigations. Default is either seccomp or prctl (if seccomp is disabled in Kconfig). prctl allows mitigation opt-in, seccomp enables the migitation for sandboxed processes. - Rework the code to handle the conditional STIBP/IBPB control and remove the now unused ptrace_may_access_sched() optimization attempt - Disable STIBP automatically when SMT is disabled - Optimize the switch_to() logic to avoid MSR writes and invocations of __switch_to_xtra(). - Make the asynchronous speculation TIF updates synchronous to prevent stale mitigation state. As a general cleanup this also makes retpoline directly depend on compiler support and removes the 'minimal retpoline' option which just pretended to provide some form of security while providing none" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) x86/speculation: Provide IBPB always command line options x86/speculation: Add seccomp Spectre v2 user space protection mode x86/speculation: Enable prctl mode for spectre_v2_user x86/speculation: Add prctl() control for indirect branch speculation x86/speculation: Prepare arch_smt_update() for PRCTL mode x86/speculation: Prevent stale SPEC_CTRL msr content x86/speculation: Split out TIF update ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS x86/speculation: Prepare for conditional IBPB in switch_mm() x86/speculation: Avoid __switch_to_xtra() calls x86/process: Consolidate and simplify switch_to_xtra() code x86/speculation: Prepare for per task indirect branch speculation control x86/speculation: Add command line control for indirect branch speculation x86/speculation: Unify conditional spectre v2 print functions x86/speculataion: Mark command line parser data __initdata x86/speculation: Mark string arrays const correctly x86/speculation: Reorder the spec_v2 code x86/l1tf: Show actual SMT state x86/speculation: Rework SMT state change sched/smt: Expose sched_smt_present static key ... -
git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block layer fixes from Jens Axboe: - Single range elevator discard merge fix, that caused crashes (Ming) - Fix for a regression in O_DIRECT, where we could potentially lose the error value (Maximilian Heyne) - NVMe pull request from Christoph, with little fixes all over the map for NVMe. * tag 'for-linus-20181201' of git://git.kernel.dk/linux-block: block: fix single range discard merge nvme-rdma: fix double freeing of async event data nvme: flush namespace scanning work just before removing namespaces nvme: warn when finding multi-port subsystems without multipathing enabled fs: fix lost error code in dio_complete nvme-pci: fix surprise removal nvme-fc: initialize nvme_req(rq)->ctrl after calling __nvme_fc_init_request() nvme: Free ctrl device name on init failure
-
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pciLinus Torvalds authored
Pull PCI fixes from Bjorn Helgaas: - Fix a link speed checking interface that broke PCIe gen3 cards in gen1 slots (Mikulas Patocka) - Fix an imx6 link training error (Trent Piepho) - Fix a layerscape outbound window accessor calling error (Hou Zhiqiang) - Fix a DesignWare endpoint MSI-X address calculation error (Gustavo Pimentel) * tag 'pci-v4.20-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: PCI: Fix incorrect value returned from pcie_get_speed_cap() PCI: dwc: Fix MSI-X EP framework address calculation bug PCI: layerscape: Fix wrong invocation of outbound window disable accessor PCI: imx6: Fix link training status detection in link up check
-
- Dec 01, 2018
-
-
Bjorn Helgaas authored
- Fix DesignWare endpoint MSI-X address calculation bug (Gustavo Pimentel) - Fix Layerscape outbound window disable usage (Hou Zhiqiang) - Fix imx6 link up detection (Trent Piepho) * lorenzo/pci/controller-fixes: PCI: dwc: Fix MSI-X EP framework address calculation bug PCI: layerscape: Fix wrong invocation of outbound window disable accessor PCI: imx6: Fix link training status detection in link up check -
Mikulas Patocka authored
The macros PCI_EXP_LNKCAP_SLS_*GB are values, not bit masks. We must mask the register and compare it against them. This fixes errors like this: amdgpu: [powerplay] failed to send message 261 ret is 0 when a PCIe-v3 card is plugged into a PCIe-v1 slot, because the slot is being incorrectly reported as PCIe-v3 capable. 6cf57be0, which appeared in v4.17, added pcie_get_speed_cap() with the incorrect test of PCI_EXP_LNKCAP_SLS as a bitmask. 5d9a6330, which appeared in v4.19, changed amdgpu to use pcie_get_speed_cap(), so the amdgpu bug reports below are regressions in v4.19. Fixes: 6cf57be0 ("PCI: Add pcie_get_speed_cap() to find max supported link speed") Fixes: 5d9a6330 ("drm/amdgpu: use pcie functions for link width and speed") Link: https://bugs.freedesktop.org/show_bug.cgi?id=108704 Link: https://bugs.freedesktop.org/show_bug.cgi?id=108778 Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> [bhelgaas: update comment, remove use of PCI_EXP_LNKCAP_SLS_8_0GB and PCI_EXP_LNKCAP_SLS_16_0GB since those should be covered by PCI_EXP_LNKCAP2, remove test of PCI_EXP_LNKCAP for zero, since that register is required] Signed-off-by:
Bjorn Helgaas <bhelgaas@google.com> Acked-by:
Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org # v4.17+
-
Linus Torvalds authored
Merge misc fixes from Andrew Morton: "31 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (31 commits) ocfs2: fix potential use after free mm/khugepaged: fix the xas_create_range() error path mm/khugepaged: collapse_shmem() do not crash on Compound mm/khugepaged: collapse_shmem() without freezing new_page mm/khugepaged: minor reorderings in collapse_shmem() mm/khugepaged: collapse_shmem() remember to clear holes mm/khugepaged: fix crashes due to misaccounted holes mm/khugepaged: collapse_shmem() stop if punched or truncated mm/huge_memory: fix lockdep complaint on 32-bit i_size_read() mm/huge_memory: splitting set mapping+index before unfreeze mm/huge_memory: rename freeze_page() to unmap_page() initramfs: clean old path before creating a hardlink kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace psi: make disabling/enabling easier for vendor kernels proc: fixup map_files test on arm debugobjects: avoid recursive calls with kmemleak userfaultfd: shmem: UFFDIO_COPY: set the page dirty if VM_WRITE is not set userfaultfd: shmem: add i_size checks userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas userfaultfd: shmem: allocate anonymous memory for MAP_PRIVATE shmem ...
-
git://git.kernel.org/pub/scm/linux/kernel/git/mips/linuxLinus Torvalds authored
Pull few more MIPS fixes from Paul Burton: - Fix mips_get_syscall_arg() to operate on the task specified when detecting o32 tasks running on MIPS64 kernels. - Fix some incorrect GPIO pin muxing for the MT7620 SoC. - Update the linux-mips mailing list address. * tag 'mips_fixes_4.20_4' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: MAINTAINERS: Update linux-mips mailing list address MIPS: ralink: Fix mt7620 nd_sd pinmux mips: fix mips_get_syscall_arg o32 check
-
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linuxLinus Torvalds authored
Pull arm64 fixes from Catalin Marinas: - Cortex-A76 erratum workaround - ftrace fix to enable syscall events on arm64 - Fix uninitialised pointer in iort_get_platform_device_domain() * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: ACPI/IORT: Fix iort_get_platform_device_domain() uninitialized pointer value arm64: ftrace: Fix to enable syscall events on arm64 arm64: Add workaround for Cortex-A76 erratum 1286807
-
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linuxLinus Torvalds authored
Pull stackleak plugin fix from Kees Cook: "Fix crash by not allowing kprobing of stackleak_erase() (Alexander Popov)" * tag 'gcc-plugins-v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: stackleak: Disable function tracing and kprobes for stackleak_erase()
-
Linus Torvalds authored
Merge tag 'fscache-fixes-20181130' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull fscache and cachefiles fixes from David Howells: "Misc fixes: - Fix an assertion failure at fs/cachefiles/xattr.c:138 caused by a race between a cache object lookup failing and someone attempting to reenable that object, thereby triggering an update of the object's attributes. - Fix an assertion failure at fs/fscache/operation.c:449 caused by a split atomic subtract and atomic read that allows a race to happen. - Fix a leak of backing pages when simultaneously reading the same page from the same object from two or more threads. - Fix a hang due to a race between a cache object being discarded and the corresponding cookie being reenabled. There are also some minor cleanups: - Cast an enum value to a different enum type to prevent clang from generating a warning. This shouldn't cause any sort of change in the emitted code. - Use ktime_get_real_seconds() instead of get_seconds(). This is just used to uniquify a filename for an object to be placed in the graveyard. Objects placed there are deleted by cachfilesd in userspace immediately thereafter. - Remove an initialised, but otherwise unused variable. This should have been entirely optimised away anyway" * tag 'fscache-fixes-20181130' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: fscache, cachefiles: remove redundant variable 'cache' cachefiles: avoid deprecated get_seconds() cachefiles: Explicitly cast enumerated type in put_object fscache: fix race between enablement and dropping of object cachefiles: Fix page leak in cachefiles_read_backing_file while vmscan is active fscache: Fix race in fscache_op_complete() due to split atomic_sub & read cachefiles: Fix an assertion failure when trying to update a failed object
-
Paul Burton authored
The linux-mips.org infrastructure has been unreliable recently & nobody with sufficient access to fix it is around to do so. As a result we're moving away from it, and part of this is migrating our mailing list to kernel.org. Replace all instances of linux-mips@linux-mips.org in MAINTAINERS with the shiny new linux-mips@vger.kernel.org address. The new list is now being archived on kernel.org at https://lore.kernel.org/linux-mips/ which also holds the history of the old linux-mips.org list. Signed-off-by:
Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: linux-mips@linux-mips.org
-
Pan Bian authored
ocfs2_get_dentry() calls iput(inode) to drop the reference count of inode, and if the reference count hits 0, inode is freed. However, in this function, it then reads inode->i_generation, which may result in a use after free bug. Move the put operation later. Link: http://lkml.kernel.org/r/1543109237-110227-1-git-send-email-bianpan2016@163.com Fixes: 781f200c ("ocfs2: Remove masklog ML_EXPORT.") Signed-off-by:
Pan Bian <bianpan2016@163.com> Reviewed-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Joseph Qi <jiangqi903@gmail.com> Cc: Changwei Ge <ge.changwei@h3c.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Hugh Dickins authored
collapse_shmem()'s xas_nomem() is very unlikely to fail, but it is rightly given a failure path, so move the whole xas_create_range() block up before __SetPageLocked(new_page): so that it does not need to remember to unlock_page(new_page). Add the missing mem_cgroup_cancel_charge(), and set (currently unused) result to SCAN_FAIL rather than SCAN_SUCCEED. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261531200.2275@eggly.anvils Fixes: 77da9389 ("mm: Convert collapse_shmem to XArray") Signed-off-by:
Hugh Dickins <hughd@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by:
-
Hugh Dickins authored
collapse_shmem()'s VM_BUG_ON_PAGE(PageTransCompound) was unsafe: before it holds page lock of the first page, racing truncation then extension might conceivably have inserted a hugepage there already. Fail with the SCAN_PAGE_COMPOUND result, instead of crashing (CONFIG_DEBUG_VM=y) or otherwise mishandling the unexpected hugepage - though later we might code up a more constructive way of handling it, with SCAN_SUCCESS. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261529310.2275@eggly.anvils Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by:
Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by:
-
Hugh Dickins authored
khugepaged's collapse_shmem() does almost all of its work, to assemble the huge new_page from 512 scattered old pages, with the new_page's refcount frozen to 0 (and refcounts of all old pages so far also frozen to 0). Including shmem_getpage() to read in any which were out on swap, memory reclaim if necessary to allocate their intermediate pages, and copying over all the data from old to new. Imagine the frozen refcount as a spinlock held, but without any lock debugging to highlight the abuse: it's not good, and under serious load heads into lockups - speculative getters of the page are not expecting to spin while khugepaged is rescheduled. One can get a little further under load by hacking around elsewhere; but fortunately, freezing the new_page turns out to have been entirely unnecessary, with no hacks needed elsewhere. The huge new_page lock is already held throughout, and guards all its subpages as they are brought one by one into the page cache tree; and anything reading the data in that page, without the lock, before it has been marked PageUptodate, would already be in the wrong. So simply eliminate the freezing of the new_page. Each of the old pages remains frozen with refcount 0 after it has been replaced by a new_page subpage in the page cache tree, until they are all unfrozen on success or failure: just as before. They could be unfrozen sooner, but cause no problem once no longer visible to find_get_entry(), filemap_map_pages() and other speculative lookups. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261527570.2275@eggly.anvils Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by:
-
Hugh Dickins authored
Several cleanups in collapse_shmem(): most of which probably do not really matter, beyond doing things in a more familiar and reassuring order. Simplify the failure gotos in the main loop, and on success update stats while interrupts still disabled from the last iteration. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261526400.2275@eggly.anvils Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by:
-
