linaro-kernel January 2012

linaro-kernel@lists.linaro.org

24 participants
32 discussions

[PATCH 1/3] procfs: Export next_tgid(), move it to kernel/pid.c

by Anton Vorontsov

We'd like to use this function in the android low memory killer driver, so let's export it. Also, move next_tgid() to kernel/pid.c, so now it lives with the rest of pid library functions and does not depend on procfs. Plus, we may now hide find_ge_pid() from the global namespace. While at it, also turn next_tgid()'s comments into kerneldoc format. There should be no functional changes. Signed-off-by: Anton Vorontsov <anton.vorontsov(a)linaro.org> --- fs/proc/base.c | 43 ------------------------------------------- include/linux/pid.h | 9 ++++++++- kernel/pid.c | 41 ++++++++++++++++++++++++++++++++++++++++- 3 files changed, 48 insertions(+), 45 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 5485a53..84b8625 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3324,49 +3324,6 @@ out: return result; } -/* - * Find the first task with tgid >= tgid - * - */ -struct tgid_iter { - unsigned int tgid; - struct task_struct *task; -}; -static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter) -{ - struct pid *pid; - - if (iter.task) - put_task_struct(iter.task); - rcu_read_lock(); -retry: - iter.task = NULL; - pid = find_ge_pid(iter.tgid, ns); - if (pid) { - iter.tgid = pid_nr_ns(pid, ns); - iter.task = pid_task(pid, PIDTYPE_PID); - /* What we to know is if the pid we have find is the - * pid of a thread_group_leader. Testing for task - * being a thread_group_leader is the obvious thing - * todo but there is a window when it fails, due to - * the pid transfer logic in de_thread. - * - * So we perform the straight forward test of seeing - * if the pid we have found is the pid of a thread - * group leader, and don't worry if the task we have - * found doesn't happen to be a thread group leader. - * As we don't care in the case of readdir. - */ - if (!iter.task || !has_group_leader_pid(iter.task)) { - iter.tgid += 1; - goto retry; - } - get_task_struct(iter.task); - } - rcu_read_unlock(); - return iter; -} - #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff)) static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir, diff --git a/include/linux/pid.h b/include/linux/pid.h index b152d44..33e350b 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -116,7 +116,6 @@ extern struct pid *find_vpid(int nr); * Lookup a PID in the hash table, and return with it's count elevated. */ extern struct pid *find_get_pid(int nr); -extern struct pid *find_ge_pid(int nr, struct pid_namespace *); int next_pidmap(struct pid_namespace *pid_ns, unsigned int last); extern struct pid *alloc_pid(struct pid_namespace *ns); @@ -199,4 +198,12 @@ pid_t pid_vnr(struct pid *pid); } while_each_thread(tg___, task); \ task = tg___; \ } while_each_pid_task(pid, type, task) + +struct tgid_iter { + unsigned int tgid; + struct task_struct *task; +}; + +struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter); + #endif /* _LINUX_PID_H */ diff --git a/kernel/pid.c b/kernel/pid.c index ce8e00d..34a52a6 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -522,7 +522,7 @@ EXPORT_SYMBOL_GPL(task_active_pid_ns); * * If there is a pid at nr this function is exactly the same as find_pid_ns. */ -struct pid *find_ge_pid(int nr, struct pid_namespace *ns) +static struct pid *find_ge_pid(int nr, struct pid_namespace *ns) { struct pid *pid; @@ -536,6 +536,45 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns) return pid; } +/** + * next_tgid() - Find the first task with tgid >= tgid + * @ns: pointer to the pid namespace + * @iter: iterator + */ +struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter) +{ + struct pid *pid; + + if (iter.task) + put_task_struct(iter.task); + rcu_read_lock(); +retry: + iter.task = NULL; + pid = find_ge_pid(iter.tgid, ns); + if (pid) { + iter.tgid = pid_nr_ns(pid, ns); + iter.task = pid_task(pid, PIDTYPE_PID); + /* What we to know is if the pid we have find is the + * pid of a thread_group_leader. Testing for task + * being a thread_group_leader is the obvious thing + * todo but there is a window when it fails, due to + * the pid transfer logic in de_thread. + * + * So we perform the straight forward test of seeing + * if the pid we have found is the pid of a thread + * group leader, and don't worry if the task we have + * found doesn't happen to be a thread group leader. + */ + if (!iter.task || !has_group_leader_pid(iter.task)) { + iter.tgid += 1; + goto retry; + } + get_task_struct(iter.task); + } + rcu_read_unlock(); + return iter; +} + /* * The pid hash table is scaled according to the amount of memory in the * machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or -- 1.7.7

12 years, 2 months

[ACTIVITY] (Deepak Saxena) January 22-28

by Deepak Saxena

== Deepak Saxena <dsaxena> == === Highlights === * Connect session planning * Released 12.01 kernel (Big thanks to Andrey!) * 12.01 monthly cycle closeout * Various conversations on phone, irc, email to discuss kernel process. === Plans === * Finish preparing for connect - Finalize any session details - Schedule meetings - Put together slides on kernel process * 1-on-1's, sub-team meetings === Travel/Time Off === * Connect + ELC 02/04-02/20 (Taking the Train from Portland -> Oakland on 02/03 afternoon. Taking days between Connect and ELC as semi-time off, will still be responding to emails but will mostly be exploring around the Bay area. Taking train back on 12/19 evening, back to work Monday 12/20 afternoon).

12 years, 2 months

[PATCH 3/3] staging: android: lowmemorykiller: Drop tasklist_lock usage

by Anton Vorontsov

Instead of walking through the whole task list (where we must hold the task list lock for the whole period while we search for the victim), let's take procfs' approach of walking up the tgids (for_each_tgit() walks a pidmap, which internally grabs an rcu lock, but only while it searches for the next tgid). Signed-off-by: Anton Vorontsov <anton.vorontsov(a)linaro.org> --- drivers/staging/android/lowmemorykiller.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c index 2d8d2b7..a9edb53 100644 --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -34,6 +34,7 @@ #include <linux/mm.h> #include <linux/oom.h> #include <linux/sched.h> +#include <linux/pid.h> #include <linux/profile.h> #include <linux/notifier.h> @@ -81,7 +82,8 @@ task_notify_func(struct notifier_block *self, unsigned long val, void *data) static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) { - struct task_struct *p; + struct pid_namespace *ns = &init_pid_ns; + struct tgid_iter iter = {}; struct task_struct *selected = NULL; int rem = 0; int tasksize; @@ -132,8 +134,8 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) } selected_oom_adj = min_adj; - read_lock(&tasklist_lock); - for_each_process(p) { + for_each_tgid(ns, iter) { + struct task_struct *p = iter.task; struct mm_struct *mm; struct signal_struct *sig; int oom_adj; @@ -160,7 +162,9 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) if (oom_adj == selected_oom_adj && tasksize <= selected_tasksize) continue; + put_task_struct(selected); } + get_task_struct(p); selected = p; selected_tasksize = tasksize; selected_oom_adj = oom_adj; @@ -181,11 +185,11 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) task_handoff_register(&task_nb); #endif force_sig(SIGKILL, selected); + put_task_struct(selected); rem -= selected_tasksize; } lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n", sc->nr_to_scan, sc->gfp_mask, rem); - read_unlock(&tasklist_lock); return rem; } -- 1.7.7

12 years, 2 months

[ACTIVITY] (Anton Vorontsov) 2012-01-23 - 2012-01-27

by Anton Vorontsov

== Highlights == * Sent out some patches to make current LMK driver don't grab tasklist lock. http://lkml.org/lkml/2012/1/29/114 http://lkml.org/lkml/2012/1/29/115 http://lkml.org/lkml/2012/1/29/116 * Continued work on adding low memory killer functionality to the Android ActivityManager and friends; * Further investigation on interactive cpufreq notifier. * Prepared some material for the android upstraming meeting; * Reviewed a bunch of battery fixes for v3.3. == Plans == * Hope to send out a bit reworked (at least it should start using new notifiers) interactive cpufreq driver mid this week; * Get a working userspace LMK by the end of this week; * Fix assorted pesky issues in the current drivers/staging/android/ (sparse and modpost warnings flood because of which I don't see newly introduced warnings). -- Anton Vorontsov Email: cbouatmailru(a)gmail.com

12 years, 2 months

[PATCH 2/3] pids: Introduce for_each_tgid() macro

by Anton Vorontsov

Just a handy macro. This patch converts procfs user to this new macro, plus android lowmemorykiller driver will use it as well. Signed-off-by: Anton Vorontsov <anton.vorontsov(a)linaro.org> --- fs/proc/base.c | 4 +--- include/linux/pid.h | 5 +++++ 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 84b8625..e815d63 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3367,9 +3367,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) ns = filp->f_dentry->d_sb->s_fs_info; iter.task = NULL; iter.tgid = filp->f_pos - TGID_OFFSET; - for (iter = next_tgid(ns, iter); - iter.task; - iter.tgid += 1, iter = next_tgid(ns, iter)) { + for_each_tgid(ns, iter) { if (has_pid_permissions(ns, iter.task, 2)) __filldir = filldir; else diff --git a/include/linux/pid.h b/include/linux/pid.h index 33e350b..da87cae 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -206,4 +206,9 @@ struct tgid_iter { struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter); +#define for_each_tgid(ns, iter) \ + for (iter = next_tgid(ns, iter); \ + iter.task; \ + iter.tgid += 1, iter = next_tgid(ns, iter)) \ + #endif /* _LINUX_PID_H */ -- 1.7.7

12 years, 2 months

[ACTIVITY] (John Stultz) Jan 23-27

by john stultz

=== Highlights === * Re-factored and reworked Android alarm driver so that it can be included into staging. Sent it out to Arve, Google Android team and GregKH for comment. Got some good feedback from Arve, and further reworked some of the patches accordingly. Will hopefully submit to staging early next week. * Reviewed Dmitry's usleep_range changes more carefully and provided feedback. * Got a little bit of time to spend on refactoring (de-recursing) the range-tree implementation in preparation of integrating it into the kernel. * Handled weekly Android-subteam email meeting * Spent the weekend & a bit of the week helping with an internal customer issue. * Spent some time catching up on community emails and issues I've flagged but not handled since the new year, including sending out some debuging patches for RTC issues. * Sent out almost the last of the clocksource_register_khz/hz cleanups for review. * Queued community RTC, clocksource and time cleanups for 3.4 along with my own rtc/time related fixes. Unfortunately tglx has been offline recently, so I've not been able to send them for queuing. * Lots of IBM internal administrative catchup from the new year. === Plans === * Submit android alarm driver to staging. * Integration of range-tree idea into kernel space and fadvise work * Review posix file locking code and determine if range-trees can be used there. * Some minor prep for Connect. === Issues === NA

12 years, 2 months

[ACTIVITY] (Linus Walleij) 2012-01-21 - 2012-01-27

by Linus Walleij

== Linus Walleij linusw == === Highlights === * Reviewed and merged some patches to pin control, Tony Lindgren is starting to show interest and submitting good patches. * Discussing pinmux ... * Reviewed different patches here and there. Tried to do some Ux500 upstreaming. * Preparing a conference presentation on pin control for the Embedded Linux Conference. This will be used as a basis for public explanation and transparency into the subject as well. * Apart from this occupied by administration (such as travel arrangements, VISA etc) and internal meetings at ST-Ericsson due to different things. === Plans === * Send patches upstream for -rc1 or -rc2. * Prepare for Linaro Connect, Android Builders and ELC. * dummy pinmuxes akin to dummy regulators, we need to see if this is a good idea or not. * Drive generalization of Nomadik GPIO by using the pinctrl framework. drivers/gpio/gpio-nomadik.c * 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... like - Ux500 clocks - the HWMON stuff. === Issues === * Tried to run a pin control meeting. Nobody from my work group turned up. Luckily I had Mounir and Tony Lindgren there to comfort me. * Ux500 mainlining having second priority. Thanks, Linus Walleij

12 years, 2 months

[Activity] (Niklas Hernaeus) 2012-01-23 - 2012-01-27

by Niklas Hernaeus

== Niklas Hernaeus <nhe> == === General activity === * Continued DT for MMC * Tried to allocate time for making plan for regulator DT. Know more next week * All administration done for going to Connect.

12 years, 2 months

[ACTIVITY] (Saugata Das) Jan 23rd - 27th

by Saugata Das

== Saugata Das sdas == === Activity Summary === * Context ID patch internal review ongoing * Reviewed packed command implementation * Reviewed power OFF notify implementation * Reviewed UFS driver implementation * Brought up Samsung MMC-4.5 JIG on 8500 board (Restriction: Only works in one bit mode due to the limitation imposed by the micro-SD/SD bridge I am using. It does not stop me from validation of features) === Plans === * Porting of SBC command support on mmci.c * Validation of context ID, tag and packed command * Submission of context ID patch === Issues === * Due to personal unavoidable reasons, I will return from Connect on 8th Feb

12 years, 2 months

Sources for 11.11 kernel release

by Chris Lalancette

(I'm aware that there is a thread on linaro-dev discussing this exact topic; this is a request for specific information, so I decided to start a new thread) Hello, As has been pointed out elsewhere, it is very difficult to find the exact git tree that corresponds to a kernel release. Currently the problem I am having is that the 11.11 linaro kernel release (linux-linaro-lt-omap_3.1.0-1402.5~oneiric1) works well on my new board, but later kernels do not. While I can download the kernel tarball for 3.1.0-1402.5 from launchpad, I would much prefer to use the git tree that it was produced from. Can anybody tell me exactly which git tree was used to create that kernel, and which tag/branch I should be looking at? Thanks, -- Chris Lalancette

12 years, 3 months

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linaro-kernel January 2012