Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756613Ab1CXJg3 (ORCPT ); Thu, 24 Mar 2011 05:36:29 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:45157 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751632Ab1CXJg1 (ORCPT ); Thu, 24 Mar 2011 05:36:27 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Thu, 24 Mar 2011 18:29:59 +0900 From: KAMEZAWA Hiroyuki To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "rientjes@google.com" , Andrey Vagin Subject: [PATCH 4/5] forkbomb : periodic flushing mm history information Message-Id: <20110324182959.ffbc6dd2.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110324182240.5fe56de2.kamezawa.hiroyu@jp.fujitsu.com> References: <20110324182240.5fe56de2.kamezawa.hiroyu@jp.fujitsu.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.1.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6958 Lines: 239 At 1st, this patch adds a control knob for enable/disable mm_history tracking. 2nd, at tracking mm's history for forkbomb detection, information of processes which doesn't seem to be important for fork-bomb detection is just a noise. This patch adds a knob for forgetting information with a periodic check routine. At every 30secs (can be configured), 1. check nr_procesess doesn't increase 2. check kswapd doesn't run 3. check allocstall doesn't occur. If all don't happens, clear mm_history which is older than 30secs. Note: reorder of objects in makefile was required because mm_kobj's initcall should be called before oom's... Signed-off-by: KAMEZAWA Hiroyuki --- mm/Makefile | 4 - mm/oom_kill.c | 144 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 139 insertions(+), 9 deletions(-) Index: mm-work2/mm/oom_kill.c =================================================================== --- mm-work2.orig/mm/oom_kill.c +++ mm-work2/mm/oom_kill.c @@ -768,6 +768,7 @@ void pagefault_out_of_memory(void) static DEFINE_PER_CPU(unsigned long, pcpu_history_lock); static DECLARE_RWSEM(hist_rwsem); static int need_global_history_lock; +static int mm_tracking_enabled = 1; static void update_history_lock(void) { @@ -841,6 +842,9 @@ void track_mm_history(struct mm_struct * { struct mm_history *hist, *phist; + if (!mm_tracking_enabled) + return; + hist = kmalloc(sizeof(*hist), GFP_KERNEL); if (!hist) return; @@ -864,19 +868,19 @@ void track_mm_history(struct mm_struct * return; } -void delete_mm_history(struct mm_struct *mm) +static void __delete_mm_history(struct mm_history *hist, bool check_ancestors) { - struct mm_history *hist, *phist; + struct mm_history *phist; bool nochild; - if (!mm->history) + if (!hist) return; - update_history_lock(); - hist = mm->history; spin_lock(&hist->lock); nochild = list_empty(&hist->children); - mm->history = NULL; - hist->mm = NULL; + if (hist->mm) { + hist->mm->history = NULL; + hist->mm = NULL; + } spin_unlock(&hist->lock); /* delete if we have no child */ while (nochild && hist != &init_hist) { @@ -887,8 +891,16 @@ void delete_mm_history(struct mm_struct nochild = (phist->mm == NULL && list_empty(&phist->children)); spin_unlock(&phist->lock); kfree(hist); + if (!check_ancestors) + break; hist = phist; } +} + +void delete_mm_history(struct mm_struct *mm) +{ + update_history_lock(); + __delete_mm_history(mm->history, true); update_history_unlock(); } @@ -951,4 +963,122 @@ static struct mm_history *mm_history_sca #define for_each_mm_history_safe(pos, tmp)\ for_each_mm_history_safe_under((pos), &init_hist, (tmp)) +static unsigned long reset_interval_jiffies = 30*HZ; +unsigned long last_nr_procs; +unsigned long last_pageout_run; +unsigned long last_allocstall; +static void reset_mm_tracking(struct work_struct *w); +DECLARE_DELAYED_WORK(reset_mm_tracking_work, reset_mm_tracking); + +static void reset_mm_tracking(struct work_struct *w) +{ + struct mm_history *pos, *tmp; + unsigned long nr_procs; + unsigned long events[NR_VM_EVENT_ITEMS]; + bool forget = true; + + nr_procs = nr_processes(); + if (nr_procs > last_nr_procs) + forget = false; + last_nr_procs = nr_procs; + + all_vm_events(events); + if (last_pageout_run != events[PAGEOUTRUN]) + forget = false; + last_pageout_run = events[PAGEOUTRUN]; + if (last_allocstall != events[ALLOCSTALL]) + forget = false; + last_allocstall = events[ALLOCSTALL]; + + if (forget) { + unsigned long thresh = jiffies - reset_interval_jiffies; + scan_history_lock(); + for_each_mm_history_safe(pos, tmp) { + if (time_before(pos->start_time, thresh)) + __delete_mm_history(pos, false); + } + scan_history_unlock(); + } + if (mm_tracking_enabled) + schedule_delayed_work(&reset_mm_tracking_work, + reset_interval_jiffies); + return; +} + +#define OOM_ATTR(_name)\ + static struct kobj_attribute _name##_attr =\ + __ATTR(_name, 0644, _name##_show, _name##_store) + +static ssize_t mm_tracker_reset_interval_msecs_show(struct kobject *obj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%u", jiffies_to_msecs(reset_interval_jiffies)); +} + +static ssize_t mm_tracker_reset_interval_msecs_store(struct kobject *obj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + unsigned long msecs; + int err; + + err = strict_strtoul(buf, 10, &msecs); + if (err || msecs > UINT_MAX) + return -EINVAL; + + reset_interval_jiffies = msecs_to_jiffies(msecs); + return count; +} +OOM_ATTR(mm_tracker_reset_interval_msecs); + +static ssize_t mm_tracker_enable_show(struct kobject *obj, + struct kobj_attribute *attr, char *buf) +{ + if (mm_tracking_enabled) + return sprintf(buf, "enabled"); + return sprintf(buf, "disabled"); +} + +static ssize_t mm_tracker_enable_store(struct kobject *obj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + if (!memcmp("disable", buf, min(sizeof("disable")-1, count))) + mm_tracking_enabled = 0; + else if (!memcmp("enable", buf, min(sizeof("enable")-1, count))) + mm_tracking_enabled = 1; + else + return -EINVAL; + if (mm_tracking_enabled + && delayed_work_pending(&reset_mm_tracking_work)) + schedule_delayed_work(&reset_mm_tracking_work, + reset_interval_jiffies); + + return count; +} +OOM_ATTR(mm_tracker_enable); + +static struct attribute *oom_attrs[] = { + &mm_tracker_reset_interval_msecs_attr.attr, + &mm_tracker_enable_attr.attr, + NULL, +}; + +static struct attribute_group oom_attr_group = { + .attrs = oom_attrs, + .name = "oom", +}; + +static int __init init_mm_history(void) +{ + int err = 0; + +#ifdef CONFIG_SYSFS + err = sysfs_create_group(mm_kobj, &oom_attr_group); + if (err) + printk(KERN_ERR + "failed to register mm history tracking for oom\n"); +#endif + schedule_delayed_work(&reset_mm_tracking_work, reset_interval_jiffies); + return 0; +} +module_init(init_mm_history); #endif Index: mm-work2/mm/Makefile =================================================================== --- mm-work2.orig/mm/Makefile +++ mm-work2/mm/Makefile @@ -7,11 +7,11 @@ mmu-$(CONFIG_MMU) := fremap.o highmem.o mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \ vmalloc.o pagewalk.o pgtable-generic.o -obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ +obj-y := mm_init.o filemap.o mempool.o oom_kill.o fadvise.o \ maccess.o page_alloc.o page-writeback.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \ - page_isolation.o mm_init.o mmu_context.o percpu.o \ + page_isolation.o mmu_context.o percpu.o \ $(mmu-y) obj-y += init-mm.o -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/