X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fcpuset.c;h=6b05dc69c9597f900f46c02ff6acaff4e9768458;hb=refs%2Fheads%2Fvserver;hp=cdc92f9728c6098b39d4d748b7a1a17c50ef46f4;hpb=16c70f8c1b54b61c3b951b6fb220df250fe09b32;p=linux-2.6.git diff --git a/kernel/cpuset.c b/kernel/cpuset.c index cdc92f972..6b05dc69c 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -240,7 +240,7 @@ static struct super_block *cpuset_sb; * A cpuset can only be deleted if both its 'count' of using tasks * is zero, and its list of 'children' cpusets is empty. Since all * tasks in the system use _some_ cpuset, and since there is always at - * least one task in the system (init, pid == 1), therefore, top_cpuset + * least one task in the system (init), therefore, top_cpuset * always has either children cpusets and/or using tasks. So we don't * need a special hack to ensure that top_cpuset cannot be deleted. * @@ -377,7 +377,7 @@ static int cpuset_fill_super(struct super_block *sb, void *unused_data, inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; /* directories start off with i_nlink == 2 (for "." entry) */ - inode->i_nlink++; + inc_nlink(inode); } else { return -ENOMEM; } @@ -413,8 +413,8 @@ static struct file_system_type cpuset_fs_type = { * * * When reading/writing to a file: - * - the cpuset to use in file->f_dentry->d_parent->d_fsdata - * - the 'cftype' of the file is file->f_dentry->d_fsdata + * - the cpuset to use in file->f_path.dentry->d_parent->d_fsdata + * - the 'cftype' of the file is file->f_path.dentry->d_fsdata */ struct cftype { @@ -729,9 +729,11 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial) } /* Remaining checks don't apply to root cpuset */ - if ((par = cur->parent) == NULL) + if (cur == &top_cpuset) return 0; + par = cur->parent; + /* We must be a subset of our parent cpuset */ if (!is_cpuset_subset(trial, par)) return -EACCES; @@ -912,6 +914,10 @@ static int update_nodemask(struct cpuset *cs, char *buf) int fudge; int retval; + /* top_cpuset.mems_allowed tracks node_online_map; it's read-only */ + if (cs == &top_cpuset) + return -EACCES; + trialcs = *cs; retval = nodelist_parse(buf, trialcs.mems_allowed); if (retval < 0) @@ -1056,10 +1062,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf) cpu_exclusive_changed = (is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs)); mutex_lock(&callback_mutex); - if (turning_on) - set_bit(bit, &cs->flags); - else - clear_bit(bit, &cs->flags); + cs->flags = trialcs.flags; mutex_unlock(&callback_mutex); if (cpu_exclusive_changed) @@ -1221,7 +1224,12 @@ static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf) task_lock(tsk); oldcs = tsk->cpuset; - if (!oldcs) { + /* + * After getting 'oldcs' cpuset ptr, be sure still not exiting. + * If 'oldcs' might be the top_cpuset due to the_top_cpuset_hack + * then fail this attach_task(), to avoid breaking top_cpuset.count. + */ + if (tsk->flags & PF_EXITING) { task_unlock(tsk); mutex_unlock(&callback_mutex); put_task_struct(tsk); @@ -1272,18 +1280,19 @@ typedef enum { FILE_TASKLIST, } cpuset_filetype_t; -static ssize_t cpuset_common_file_write(struct file *file, const char __user *userbuf, +static ssize_t cpuset_common_file_write(struct file *file, + const char __user *userbuf, size_t nbytes, loff_t *unused_ppos) { - struct cpuset *cs = __d_cs(file->f_dentry->d_parent); - struct cftype *cft = __d_cft(file->f_dentry); + struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent); + struct cftype *cft = __d_cft(file->f_path.dentry); cpuset_filetype_t type = cft->private; char *buffer; char *pathbuf = NULL; int retval = 0; /* Crude upper limit on largest legitimate cpulist user might write. */ - if (nbytes > 100 + 6 * NR_CPUS) + if (nbytes > 100 + 6 * max(NR_CPUS, MAX_NUMNODES)) return -E2BIG; /* +1 for nul-terminator */ @@ -1358,7 +1367,7 @@ static ssize_t cpuset_file_write(struct file *file, const char __user *buf, size_t nbytes, loff_t *ppos) { ssize_t retval = 0; - struct cftype *cft = __d_cft(file->f_dentry); + struct cftype *cft = __d_cft(file->f_path.dentry); if (!cft) return -ENODEV; @@ -1408,8 +1417,8 @@ static int cpuset_sprintf_memlist(char *page, struct cpuset *cs) static ssize_t cpuset_common_file_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { - struct cftype *cft = __d_cft(file->f_dentry); - struct cpuset *cs = __d_cs(file->f_dentry->d_parent); + struct cftype *cft = __d_cft(file->f_path.dentry); + struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent); cpuset_filetype_t type = cft->private; char *page; ssize_t retval = 0; @@ -1467,7 +1476,7 @@ static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbyt loff_t *ppos) { ssize_t retval = 0; - struct cftype *cft = __d_cft(file->f_dentry); + struct cftype *cft = __d_cft(file->f_path.dentry); if (!cft) return -ENODEV; @@ -1489,7 +1498,7 @@ static int cpuset_file_open(struct inode *inode, struct file *file) if (err) return err; - cft = __d_cft(file->f_dentry); + cft = __d_cft(file->f_path.dentry); if (!cft) return -ENODEV; if (cft->open) @@ -1502,7 +1511,7 @@ static int cpuset_file_open(struct inode *inode, struct file *file) static int cpuset_file_release(struct inode *inode, struct file *file) { - struct cftype *cft = __d_cft(file->f_dentry); + struct cftype *cft = __d_cft(file->f_path.dentry); if (cft->release) return cft->release(inode, file); return 0; @@ -1523,7 +1532,7 @@ static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry, return simple_rename(old_dir, old_dentry, new_dir, new_dentry); } -static struct file_operations cpuset_file_operations = { +static const struct file_operations cpuset_file_operations = { .read = cpuset_file_read, .write = cpuset_file_write, .llseek = generic_file_llseek, @@ -1556,7 +1565,7 @@ static int cpuset_create_file(struct dentry *dentry, int mode) inode->i_fop = &simple_dir_operations; /* start off with i_nlink == 2 (for "." entry) */ - inode->i_nlink++; + inc_nlink(inode); } else if (S_ISREG(mode)) { inode->i_size = 0; inode->i_fop = &cpuset_file_operations; @@ -1589,7 +1598,7 @@ static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode) error = cpuset_create_file(dentry, S_IFDIR | mode); if (!error) { dentry->d_fsdata = cs; - parent->d_inode->i_nlink++; + inc_nlink(parent->d_inode); cs->dentry = dentry; } dput(dentry); @@ -1691,7 +1700,7 @@ static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids) */ static int cpuset_tasks_open(struct inode *unused, struct file *file) { - struct cpuset *cs = __d_cs(file->f_dentry->d_parent); + struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent); struct ctr_struct *ctr; pid_t *pidarray; int npids; @@ -2024,7 +2033,7 @@ int __init cpuset_init(void) } root = cpuset_mount->mnt_sb->s_root; root->d_fsdata = &top_cpuset; - root->d_inode->i_nlink++; + inc_nlink(root->d_inode); top_cpuset.dentry = root; root->d_inode->i_op = &cpuset_dir_inode_operations; number_of_cpusets = 1; @@ -2037,30 +2046,97 @@ out: } /* - * The top_cpuset tracks what CPUs and Memory Nodes are online, - * period. This is necessary in order to make cpusets transparent - * (of no affect) on systems that are actively using CPU hotplug - * but making no active use of cpusets. - * - * This handles CPU hotplug (cpuhp) events. If someday Memory - * Nodes can be hotplugged (dynamically changing node_online_map) - * then we should handle that too, perhaps in a similar way. + * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs + * or memory nodes, we need to walk over the cpuset hierarchy, + * removing that CPU or node from all cpusets. If this removes the + * last CPU or node from a cpuset, then the guarantee_online_cpus() + * or guarantee_online_mems() code will use that emptied cpusets + * parent online CPUs or nodes. Cpusets that were already empty of + * CPUs or nodes are left empty. + * + * This routine is intentionally inefficient in a couple of regards. + * It will check all cpusets in a subtree even if the top cpuset of + * the subtree has no offline CPUs or nodes. It checks both CPUs and + * nodes, even though the caller could have been coded to know that + * only one of CPUs or nodes needed to be checked on a given call. + * This was done to minimize text size rather than cpu cycles. + * + * Call with both manage_mutex and callback_mutex held. + * + * Recursive, on depth of cpuset subtree. */ -#ifdef CONFIG_HOTPLUG_CPU -static int cpuset_handle_cpuhp(struct notifier_block *nb, - unsigned long phase, void *cpu) +static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur) +{ + struct cpuset *c; + + /* Each of our child cpusets mems must be online */ + list_for_each_entry(c, &cur->children, sibling) { + guarantee_online_cpus_mems_in_subtree(c); + if (!cpus_empty(c->cpus_allowed)) + guarantee_online_cpus(c, &c->cpus_allowed); + if (!nodes_empty(c->mems_allowed)) + guarantee_online_mems(c, &c->mems_allowed); + } +} + +/* + * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track + * cpu_online_map and node_online_map. Force the top cpuset to track + * whats online after any CPU or memory node hotplug or unplug event. + * + * To ensure that we don't remove a CPU or node from the top cpuset + * that is currently in use by a child cpuset (which would violate + * the rule that cpusets must be subsets of their parent), we first + * call the recursive routine guarantee_online_cpus_mems_in_subtree(). + * + * Since there are two callers of this routine, one for CPU hotplug + * events and one for memory node hotplug events, we could have coded + * two separate routines here. We code it as a single common routine + * in order to minimize text size. + */ + +static void common_cpu_mem_hotplug_unplug(void) { mutex_lock(&manage_mutex); mutex_lock(&callback_mutex); + guarantee_online_cpus_mems_in_subtree(&top_cpuset); top_cpuset.cpus_allowed = cpu_online_map; + top_cpuset.mems_allowed = node_online_map; mutex_unlock(&callback_mutex); mutex_unlock(&manage_mutex); +} +/* + * The top_cpuset tracks what CPUs and Memory Nodes are online, + * period. This is necessary in order to make cpusets transparent + * (of no affect) on systems that are actively using CPU hotplug + * but making no active use of cpusets. + * + * This routine ensures that top_cpuset.cpus_allowed tracks + * cpu_online_map on each CPU hotplug (cpuhp) event. + */ + +static int cpuset_handle_cpuhp(struct notifier_block *nb, + unsigned long phase, void *cpu) +{ + common_cpu_mem_hotplug_unplug(); return 0; } + +#ifdef CONFIG_MEMORY_HOTPLUG +/* + * Keep top_cpuset.mems_allowed tracking node_online_map. + * Call this routine anytime after you change node_online_map. + * See also the previous routine cpuset_handle_cpuhp(). + */ + +void cpuset_track_online_nodes(void) +{ + common_cpu_mem_hotplug_unplug(); +} #endif /** @@ -2244,7 +2320,7 @@ int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl) int i; for (i = 0; zl->zones[i]; i++) { - int nid = zl->zones[i]->zone_pgdat->node_id; + int nid = zone_to_nid(zl->zones[i]); if (node_isset(nid, current->mems_allowed)) return 1; @@ -2266,32 +2342,48 @@ static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs) } /** - * cpuset_zone_allowed - Can we allocate memory on zone z's memory node? + * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node? * @z: is this zone on an allowed node? - * @gfp_mask: memory allocation flags (we use __GFP_HARDWALL) + * @gfp_mask: memory allocation flags * - * If we're in interrupt, yes, we can always allocate. If zone + * If we're in interrupt, yes, we can always allocate. If + * __GFP_THISNODE is set, yes, we can always allocate. If zone * z's node is in our tasks mems_allowed, yes. If it's not a * __GFP_HARDWALL request and this zone's nodes is in the nearest * mem_exclusive cpuset ancestor to this tasks cpuset, yes. * Otherwise, no. * + * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall() + * reduces to cpuset_zone_allowed_hardwall(). Otherwise, + * cpuset_zone_allowed_softwall() might sleep, and might allow a zone + * from an enclosing cpuset. + * + * cpuset_zone_allowed_hardwall() only handles the simpler case of + * hardwall cpusets, and never sleeps. + * + * The __GFP_THISNODE placement logic is really handled elsewhere, + * by forcibly using a zonelist starting at a specified node, and by + * (in get_page_from_freelist()) refusing to consider the zones for + * any node on the zonelist except the first. By the time any such + * calls get to this routine, we should just shut up and say 'yes'. + * * GFP_USER allocations are marked with the __GFP_HARDWALL bit, * and do not allow allocations outside the current tasks cpuset. * GFP_KERNEL allocations are not so marked, so can escape to the - * nearest mem_exclusive ancestor cpuset. + * nearest enclosing mem_exclusive ancestor cpuset. * - * Scanning up parent cpusets requires callback_mutex. The __alloc_pages() - * routine only calls here with __GFP_HARDWALL bit _not_ set if - * it's a GFP_KERNEL allocation, and all nodes in the current tasks - * mems_allowed came up empty on the first pass over the zonelist. - * So only GFP_KERNEL allocations, if all nodes in the cpuset are - * short of memory, might require taking the callback_mutex mutex. + * Scanning up parent cpusets requires callback_mutex. The + * __alloc_pages() routine only calls here with __GFP_HARDWALL bit + * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the + * current tasks mems_allowed came up empty on the first pass over + * the zonelist. So only GFP_KERNEL allocations, if all nodes in the + * cpuset are short of memory, might require taking the callback_mutex + * mutex. * * The first call here from mm/page_alloc:get_page_from_freelist() - * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, so - * no allocation on a node outside the cpuset is allowed (unless in - * interrupt, of course). + * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, + * so no allocation on a node outside the cpuset is allowed (unless + * in interrupt, of course). * * The second pass through get_page_from_freelist() doesn't even call * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() @@ -2304,20 +2396,20 @@ static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs) * GFP_USER - only nodes in current tasks mems allowed ok. * * Rule: - * Don't call cpuset_zone_allowed() if you can't sleep, unless you + * Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables * the code that might scan up ancestor cpusets and sleep. - **/ + */ -int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) +int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask) { int node; /* node that zone z is on */ const struct cpuset *cs; /* current cpuset ancestors */ int allowed; /* is allocation in zone z allowed? */ - if (in_interrupt()) + if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) return 1; - node = z->zone_pgdat->node_id; + node = zone_to_nid(z); might_sleep_if(!(gfp_mask & __GFP_HARDWALL)); if (node_isset(node, current->mems_allowed)) return 1; @@ -2339,6 +2431,40 @@ int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) return allowed; } +/* + * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node? + * @z: is this zone on an allowed node? + * @gfp_mask: memory allocation flags + * + * If we're in interrupt, yes, we can always allocate. + * If __GFP_THISNODE is set, yes, we can always allocate. If zone + * z's node is in our tasks mems_allowed, yes. Otherwise, no. + * + * The __GFP_THISNODE placement logic is really handled elsewhere, + * by forcibly using a zonelist starting at a specified node, and by + * (in get_page_from_freelist()) refusing to consider the zones for + * any node on the zonelist except the first. By the time any such + * calls get to this routine, we should just shut up and say 'yes'. + * + * Unlike the cpuset_zone_allowed_softwall() variant, above, + * this variant requires that the zone be in the current tasks + * mems_allowed or that we're in interrupt. It does not scan up the + * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset. + * It never sleeps. + */ + +int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask) +{ + int node; /* node that zone z is on */ + + if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) + return 1; + node = zone_to_nid(z); + if (node_isset(node, current->mems_allowed)) + return 1; + return 0; +} + /** * cpuset_lock - lock out any changes to cpuset structures *