linaro-kernel December 2012

linaro-kernel@lists.linaro.org

22 participants
27 discussions

Re: ACPI 5.0 implementation for armv7 and armv8 archoitecture

by Leif Lindholm

Hi, > I am planning to implement ACPI5.0 on an SOC having Cortex A5 and > Atlas cpu( based on armv8 architecture) running linux on top of > them. Will they both be needing ACPI? Cortex-A5 is an ARMv7 processor. > As per the ACPI 5.0 hardware specification(Fixed Hardware/ Generic > Hardware model) of ACPI5.0, the processor needs to support various > low power modes(C0, C1, C2, C3) and sleep states(S1, S2, S3, S4, S5) > via register interfaces as well as OEM provided AML(ACPI Machine > Language). OK. > Therefore, which instructions in armv7 and armv8 put the processor > into the afore-mentioned low power modes and sleep states? > ( The arm instruction manual specifies "wfe" and "wfi" to put the > processor in a sleep state, but I am not sure if this confirms to > the ACPI 5.0 requirements ) As I see it, C0 and C1 are straightforward enough: C0 is "running" and C1 is corresponding to simply executing WFI/WFE without any further use of power management hardware support. To reach C2 and C3, interaction with a power controller will be necessary. The same is true for S1-S5. ARM has started to work on interfaces to enable the use of generic software in power management solutions. One example of this of the Power State Coordination Interface document: http://infocenter.arm.com/help/topic/com.arm.doc.den0022a/index.html (free registration required). It does not however contain ACPI-specific information. > Besides, does arm provide any AML(ACPI Machine Language) code to put > the processor to low power modes? If not, then how do we create an > ACPI machine language code for armv7 and armv8 architecture and do > we have an AML interpreter for armv7 and armv8 architecture? Not as far as I'm aware. Some work on ACPI for ARM is being planned by the Linaro Enterprise Group. / Leif

11 years, 5 months

[ACTIVITY] (Dong Aisheng) 2012-11-20 - 2012-12-03

by Dong Aisheng

* KVM/ARM VGIC state saving and restoring implementation. Completed the initial RFC patch and sent it out. [RFC PATCH 1/1] KVM: ARM: add vgic state save and restore support During the implementation, I met a lot issues and some of them were hard to make decision. There're two different ways to implement such function, however, each way has different issues. I currently can not make sure which one is better. So i raised them in the RFC patch and request for people's comments and suggestions.

11 years, 5 months

[ACTIVITY] (Rajanikanth H V) 2012-11-26 to 2012-11-30

by Rajanikanth HV

==== Activity Summary ==== - Communicated final patch to anton regarding ab8500 BM devices which is over the - Communicated detailed observation with possible suspect on snowball ethernet issue to linus, lee. lee suggested a clk related patch(http://paste.ubuntu.com/1396710/) from linus which did not help - Discussion with arnd on Runtime size analysis, finalized steps to analyze and test, updated blueprint accordingly. - Discussion with shawnguo regarding i.MX support for runtime size information, understood that some of the drivers does not support module build, same with u8500 as well - Completed first cut Static data gathering from vmlinux across all the platforms ==== Plan ==== * Work on runtime on zImage size analysis across U8500, OMAP, VExpress and i.MX * Discuss with arnd on runtime size analysis under the case where some of the drivers does not support module build ==== Issues ==== -- NA --

11 years, 5 months

ACPI 5.0 implementation for armv7 and armv8 archoitecture

by Ayan Halder

Hi, I am planning to implement ACPI5.0 on an SOC having Cortex A5 and Atlas cpu( based on armv8 architecture) running linux on top of them. As per the ACPI 5.0 hardware specification(Fixed Hardware/ Generic Hardware model) of ACPI5.0, the processor needs to support various low power modes(C0, C1, C2, C3) and sleep states(S1, S2, S3, S4, S5) via register interfaces as well as OEM provided AML(ACPI Machine Language). Therefore, which instructions in armv7 and armv8 put the processor into the afore-mentioned low power modes and sleep states? ( The arm instruction manual specifies "wfe" and "wfi" to put the processor in a sleep state, but I am not sure if this confirms to the ACPI 5.0 requirements ) Besides, does arm provide any AML(ACPI Machine Language) code to put the processor to low power modes? If not, then how do we create an ACPI machine language code for armv7 and armv8 architecture and do we have an AML interpreter for armv7 and armv8 architecture? Regards, Ayan Kumar Halder

11 years, 5 months

[ACTIVITY] (Linus Walleij) 2012-11-24 - 2012-12-02

by Linus Walleij

== Linus Walleij linusw == === Highlights === * Got sidetracked for two days by a regression in the clk subsystem for ux500 found by Lee Jones. Since I try to police this platform whenever something breaks I will be the last resort. Finally nailed and fixed the bug after first doing the completely wrong thing, resulting in a one-liner patch. No idea on how to blueprint/track such things, ideas welcome. * Hardening and lining up pinctrl patches for the next merge window. * Synchronized GPIO trees with Grant. * Reviewed a patch set of 77 patches from Laurent Pinchard moving the SH architecture over to using pin control. Did this by reviewing the end result, needless to say this took some time. * Sent Integrator pull requests to ARM SoC. === Plans === * Attack the remaining headers in arch/arm/mach-ux500 so we can move forward with multiplatform for v3.9. * Test the PL08x patches on the Ericsson Research PB11MPCore and submit platform data for using pl08x DMA on that platform. * Look into other Ux500 stuff in need of mainlining... using an internal tracking sheet for this. * Look into regmap. Try something out, get to know it. === Issues === * Had to take a day off to watch over my daughter. * Had to put time aside for internal career development. Thanks, Linus Walleij

11 years, 5 months

[RFC] Add mempressure cgroup

by Anton Vorontsov

This is an attempt to implement David Rientjes' idea of mempressure cgroup. The main characteristics are the same to what I've tried to add to vmevent API: Internally, it uses Mel Gorman's idea of scanned/reclaimed ratio for pressure index calculation. But we don't expose the index to the userland. Instead, there are three levels of the pressure: o low (just reclaiming, e.g. caches are draining); o medium (allocation cost becomes high, e.g. swapping); o oom (about to oom very soon). The rationale behind exposing levels and not the raw pressure index described here: http://lkml.org/lkml/2012/11/16/675 The API uses standard cgroups eventfd notifications: $ gcc Documentation/cgroups/cgroup_event_listener.c -o \ cgroup_event_listener $ cd /sys/fs/cgroup/ $ mkdir mempressure $ mount -t cgroup cgroup ./mempressure -o mempressure $ cd mempressure $ cgroup_event_listener ./mempressure.level low ("low", "medium", "oom" are permitted values.) Upon hitting the threshold, you should see "/sys/fs/cgroup/mempressure low: crossed" messages. To test that it actually works on per-cgroup basis, I did a small trick: I moved all kswapd into a separate cgroup, and hooked the listener onto another (non-root) cgroup. The listener no longer received global reclaim pressure, which is expected. For a task it is possible to be in both cpusets, memcg and mempressure cgroups, so by rearranging the tasks it should be possible to watch a specific pressure. Note that while this adds the cgroups support, the code is well separated and eventually we might add a lightweight, non-cgroups API, i.e. vmevent. But this is another story. Signed-off-by: Anton Vorontsov <anton.vorontsov(a)linaro.org> --- include/linux/cgroup_subsys.h | 6 + include/linux/vmstat.h | 8 ++ init/Kconfig | 5 + mm/Makefile | 1 + mm/mempressure.c | 287 ++++++++++++++++++++++++++++++++++++++++++ mm/vmscan.c | 3 + 6 files changed, 310 insertions(+) create mode 100644 mm/mempressure.c diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h index f204a7a..b9802e2 100644 --- a/include/linux/cgroup_subsys.h +++ b/include/linux/cgroup_subsys.h @@ -37,6 +37,12 @@ SUBSYS(mem_cgroup) /* */ +#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_MEMPRESSURE) +SUBSYS(mpc_cgroup) +#endif + +/* */ + #if IS_SUBSYS_ENABLED(CONFIG_CGROUP_DEVICE) SUBSYS(devices) #endif diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 92a86b2..7698341 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -10,6 +10,14 @@ extern int sysctl_stat_interval; +#ifdef CONFIG_CGROUP_MEMPRESSURE +extern void vmpressure(ulong scanned, ulong reclaimed); +extern void vmpressure_prio(int prio); +#else +static inline void vmpressure(ulong scanned, ulong reclaimed) {} +static inline void vmpressure_prio(int prio) {} +#endif + #ifdef CONFIG_VM_EVENT_COUNTERS /* * Light weight per cpu counter implementation. diff --git a/init/Kconfig b/init/Kconfig index 6fdd6e3..7065e44 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -826,6 +826,11 @@ config MEMCG_KMEM the kmem extension can use it to guarantee that no group of processes will ever exhaust kernel resources alone. +config CGROUP_MEMPRESSURE + bool "Memory pressure monitor for Control Groups" + help + TODO + config CGROUP_HUGETLB bool "HugeTLB Resource Controller for Control Groups" depends on RESOURCE_COUNTERS && HUGETLB_PAGE && EXPERIMENTAL diff --git a/mm/Makefile b/mm/Makefile index 6b025f8..40cee19 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -50,6 +50,7 @@ obj-$(CONFIG_MIGRATION) += migrate.o obj-$(CONFIG_QUICKLIST) += quicklist.o obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o obj-$(CONFIG_MEMCG) += memcontrol.o page_cgroup.o +obj-$(CONFIG_CGROUP_MEMPRESSURE) += mempressure.o obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o diff --git a/mm/mempressure.c b/mm/mempressure.c new file mode 100644 index 0000000..5c85bbe --- /dev/null +++ b/mm/mempressure.c @@ -0,0 +1,287 @@ +/* + * Linux VM pressure notifications + * + * Copyright 2012 Linaro Ltd. + * Anton Vorontsov <anton.vorontsov(a)linaro.org> + * + * Based on ideas from David Rientjes, KOSAKI Motohiro, Leonid Moiseichuk, + * Mel Gorman, Minchan Kim and Pekka Enberg. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + */ + +#include <linux/cgroup.h> +#include <linux/fs.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/vmstat.h> +#include <linux/atomic.h> +#include <linux/eventfd.h> +#include <linux/swap.h> +#include <linux/printk.h> + +static void mpc_vmpressure(ulong scanned, ulong reclaimed); + +/* + * Generic VM Pressure routines (no cgroups or any other API details) + */ + +/* These are defaults. Might make them configurable one day. */ +static const uint vmpressure_win = SWAP_CLUSTER_MAX * 16; +static const uint vmpressure_level_med = 60; +static const uint vmpressure_level_oom = 99; +static const uint vmpressure_level_oom_prio = 4; + +enum vmpressure_levels { + VMPRESSURE_LOW = 0, + VMPRESSURE_MEDIUM, + VMPRESSURE_OOM, + VMPRESSURE_NUM_LEVELS, +}; + +static const char const *vmpressure_str_levels[] = { + [VMPRESSURE_LOW] = "low", + [VMPRESSURE_MEDIUM] = "medium", + [VMPRESSURE_OOM] = "oom", +}; + +static enum vmpressure_levels vmpressure_level(uint pressure) +{ + if (pressure >= vmpressure_level_oom) + return VMPRESSURE_OOM; + else if (pressure >= vmpressure_level_med) + return VMPRESSURE_MEDIUM; + return VMPRESSURE_LOW; +} + +static ulong vmpressure_calc_level(uint win, uint s, uint r) +{ + ulong p; + + if (!s) + return 0; + + /* + * We calculate the ratio (in percents) of how many pages were + * scanned vs. reclaimed in a given time frame (window). Note that + * time is in VM reclaimer's "ticks", i.e. number of pages + * scanned. This makes it possible to set desired reaction time + * and serves as a ratelimit. + */ + p = win - (r * win / s); + p = p * 100 / win; + + pr_debug("%s: %3lu (s: %6u r: %6u)\n", __func__, p, s, r); + + return vmpressure_level(p); +} + +void vmpressure(ulong scanned, ulong reclaimed) +{ + if (!scanned) + return; + mpc_vmpressure(scanned, reclaimed); +} + +void vmpressure_prio(int prio) +{ + if (prio > vmpressure_level_oom_prio) + return; + + /* OK, the prio is below the threshold, send the pre-OOM event. */ + vmpressure(vmpressure_win, 0); +} + +/* + * Memory pressure cgroup code + */ + +struct mpc_state { + struct cgroup_subsys_state css; + uint scanned; + uint reclaimed; + struct mutex lock; + struct eventfd_ctx *eventfd; + enum vmpressure_levels thres; +}; + +static struct mpc_state *css2mpc(struct cgroup_subsys_state *css) +{ + return container_of(css, struct mpc_state, css); +} + +static struct mpc_state *tsk2mpc(struct task_struct *tsk) +{ + return css2mpc(task_subsys_state(tsk, mpc_cgroup_subsys_id)); +} + +static struct mpc_state *cg2mpc(struct cgroup *cg) +{ + return css2mpc(cgroup_subsys_state(cg, mpc_cgroup_subsys_id)); +} + +static void __mpc_vmpressure(ulong scanned, ulong reclaimed) +{ + struct mpc_state *mpc = tsk2mpc(current); + int level; + + mpc->scanned += scanned; + mpc->reclaimed += reclaimed; + + if (mpc->scanned < vmpressure_win) + return; + + level = vmpressure_calc_level(vmpressure_win, + mpc->scanned, mpc->reclaimed); + if (level >= mpc->thres) { + mutex_lock(&mpc->lock); + if (mpc->eventfd) + eventfd_signal(mpc->eventfd, 1); + mutex_unlock(&mpc->lock); + } +} + +static void mpc_vmpressure(ulong scanned, ulong reclaimed) +{ + /* + * There are two options for implementing cgroup pressure + * notifications: + * + * - Store pressure counter atomically in the task struct. Upon + * hitting 'window' wake up a workqueue that will walk every + * task and sum per-thread pressure into cgroup pressure (to + * which the task belongs). The cons are obvious: bloats task + * struct, have to walk all processes and makes pressue less + * accurate (the window becomes per-thread); + * + * - Store pressure counters in per-cgroup state. This is easy and + * straighforward, and that's how we do things here. But this + * requires us to not put the vmpressure hooks into hotpath, + * since we have to grab some locks. + */ + task_lock(current); + __mpc_vmpressure(scanned, reclaimed); + task_unlock(current); +} + +static struct cgroup_subsys_state *mpc_create(struct cgroup *cg) +{ + struct mpc_state *mpc; + + mpc = kzalloc(sizeof(*mpc), GFP_KERNEL); + if (!mpc) + return ERR_PTR(-ENOMEM); + + mutex_init(&mpc->lock); + + return &mpc->css; +} + +static int mpc_pre_destroy(struct cgroup *cg) +{ + struct mpc_state *mpc = cg2mpc(cg); + int ret = 0; + + mutex_lock(&mpc->lock); + + if (mpc->eventfd) + ret = -EBUSY; + + mutex_unlock(&mpc->lock); + + return ret; +} + +static void mpc_destroy(struct cgroup *cg) +{ + struct mpc_state *mpc = cg2mpc(cg); + + kfree(mpc); +} + +static ssize_t mpc_read_level(struct cgroup *cg, struct cftype *cft, + struct file *file, char __user *buf, + size_t sz, loff_t *ppos) +{ + struct mpc_state *mpc = cg2mpc(cg); + uint level; + const char *str; + + mutex_lock(&mpc->lock); + + level = vmpressure_calc_level(vmpressure_win, + mpc->scanned, mpc->reclaimed); + mpc->scanned = 0; + mpc->reclaimed = 0; + + mutex_unlock(&mpc->lock); + + str = vmpressure_str_levels[level]; + return simple_read_from_buffer(buf, sz, ppos, str, strlen(str)); +} + +static int mpc_register_level_event(struct cgroup *cg, struct cftype *cft, + struct eventfd_ctx *eventfd, + const char *args) +{ + struct mpc_state *mpc = cg2mpc(cg); + int i; + int ret; + + mutex_lock(&mpc->lock); + + /* + * It's easy to implement multiple thresholds, but so far we don't + * need it. + */ + if (mpc->eventfd) { + ret = -EBUSY; + goto out_unlock; + } + + ret = -EINVAL; + for (i = 0; i < VMPRESSURE_NUM_LEVELS; i++) { + if (strcmp(vmpressure_str_levels[i], args)) + continue; + mpc->eventfd = eventfd; + mpc->thres = i; + ret = 0; + break; + } +out_unlock: + mutex_unlock(&mpc->lock); + + return ret; +} + +static void mpc_unregister_level_event(struct cgroup *cg, struct cftype *cft, + struct eventfd_ctx *eventfd) +{ + struct mpc_state *mpc = cg2mpc(cg); + + mutex_lock(&mpc->lock); + BUG_ON(mpc->eventfd != eventfd); + mpc->eventfd = NULL; + mutex_unlock(&mpc->lock); +} + +static struct cftype mpc_files[] = { + { + .name = "level", + .read = mpc_read_level, + .register_event = mpc_register_level_event, + .unregister_event = mpc_unregister_level_event, + }, + {}, +}; + +struct cgroup_subsys mpc_cgroup_subsys = { + .name = "mempressure", + .subsys_id = mpc_cgroup_subsys_id, + .create = mpc_create, + .pre_destroy = mpc_pre_destroy, + .destroy = mpc_destroy, + .base_cftypes = mpc_files, +}; diff --git a/mm/vmscan.c b/mm/vmscan.c index 48550c6..430d8a5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1877,6 +1877,8 @@ restart: shrink_active_list(SWAP_CLUSTER_MAX, lruvec, sc, LRU_ACTIVE_ANON); + vmpressure(sc->nr_scanned - nr_scanned, nr_reclaimed); + /* reclaim/compaction might need reclaim to continue */ if (should_continue_reclaim(lruvec, nr_reclaimed, sc->nr_scanned - nr_scanned, sc)) @@ -2099,6 +2101,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, count_vm_event(ALLOCSTALL); do { + vmpressure_prio(sc->priority); sc->nr_scanned = 0; aborted_reclaim = shrink_zones(zonelist, sc); -- 1.8.0

11 years, 5 months

[ACTIVITY] (John Stultz) Nov 26-30

by John Stultz

=== Highlights === * Continued playing with and hacking on Minchan's vma based anonymous volatile range patch * Lots of reading of the madvise/mmap/rmap code * Found a few bugs with Minchan's approach and resolved them * Got Minchan's approach working w/ files, so it can be used on tmpfs * Sent out my git tree of changes for review to lkml * Sent out weekly upstreaming status mail * Reviewed a merge_config.sh patch * Replied to some mails about perf timestamps and ntp behavior === Plans === * Continue hacking on the vma/madvise approach to volatile ranges. - Try to add limits so it returns -EINVAL on non-tmpfs filesystems - Find a way to deal with aging anonymous pages so we purge volatile ranges in the swapoff case - Integrate this approach into the ashmem driver * Re-merge Anton's 3.7 forward port of the android patchset into my linaro-android tree - Add fixes from Tixy and others that are pending - Possibly re-update the tree from the 3.4 branch * Bunch of other community issues to look at again === Issues === * NA

11 years, 5 months

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linaro-kernel December 2012