https://github.com/torvalds/linux
Revision 6111da3432b10b2c56a21a5d8671aee46435326d authored by Linus Torvalds on 27 September 2014, 23:45:33 UTC, committed by Linus Torvalds on 27 September 2014, 23:45:33 UTC
Pull cgroup fixes from Tejun Heo: "This is quite late but these need to be backported anyway. This is the fix for a long-standing cpuset bug which existed from 2009. cpuset makes use of PF_SPREAD_{PAGE|SLAB} flags to modify the task's memory allocation behavior according to the settings of the cpuset it belongs to; unfortunately, when those flags have to be changed, cpuset did so directly even whlie the target task is running, which is obviously racy as task->flags may be modified by the task itself at any time. This obscure bug manifested as corrupt PF_USED_MATH flag leading to a weird crash. The bug is fixed by moving the flag to task->atomic_flags. The first two are prepatory ones to help defining atomic_flags accessors and the third one is the actual fix" * 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags sched: add macros to define bitops for task atomic flags sched: fix confusing PFA_NO_NEW_PRIVS constant
Tip revision: 6111da3432b10b2c56a21a5d8671aee46435326d authored by Linus Torvalds on 27 September 2014, 23:45:33 UTC
Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Tip revision: 6111da3
drop_caches.c
/*
* Implement the manual drop-all-pagecache function
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/writeback.h>
#include <linux/sysctl.h>
#include <linux/gfp.h>
#include "internal.h"
/* A global variable is a bit ugly, but it keeps the code simple */
int sysctl_drop_caches;
static void drop_pagecache_sb(struct super_block *sb, void *unused)
{
struct inode *inode, *toput_inode = NULL;
spin_lock(&inode_sb_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
(inode->i_mapping->nrpages == 0)) {
spin_unlock(&inode->i_lock);
continue;
}
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_sb_list_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
toput_inode = inode;
spin_lock(&inode_sb_list_lock);
}
spin_unlock(&inode_sb_list_lock);
iput(toput_inode);
}
static void drop_slab(void)
{
int nr_objects;
struct shrink_control shrink = {
.gfp_mask = GFP_KERNEL,
};
nodes_setall(shrink.nodes_to_scan);
do {
nr_objects = shrink_slab(&shrink, 1000, 1000);
} while (nr_objects > 10);
}
int drop_caches_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
int ret;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (ret)
return ret;
if (write) {
static int stfu;
if (sysctl_drop_caches & 1) {
iterate_supers(drop_pagecache_sb, NULL);
count_vm_event(DROP_PAGECACHE);
}
if (sysctl_drop_caches & 2) {
drop_slab();
count_vm_event(DROP_SLAB);
}
if (!stfu) {
pr_info("%s (%d): drop_caches: %d\n",
current->comm, task_pid_nr(current),
sysctl_drop_caches);
}
stfu |= sysctl_drop_caches & 4;
}
return 0;
}
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...