The patch titled cpuset: don't allocate trial cpuset on stack has been added to the -mm tree. Its filename is cpuset-dont-allocate-trial-cpuset-on-stack.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: cpuset: don't allocate trial cpuset on stack From: Li Zefan <lizf@xxxxxxxxxxxxxx> Impact: cleanups, reduce stack usage This patch prepares for the next patch. When we convert cpuset.cpus_allowed to cpumask_var_t, (trialcs = *cs) no longer works. Another result of this patch is reducing stack usage of trialcs. sizeof(*cs) can be as large as 148 bytes on x86_64, so it's really not good to have it on stack. Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Acked-by: Mike Travis <travis@xxxxxxx> Cc: Paul Menage <menage@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/cpuset.c | 93 +++++++++++++++++++++++++++++----------------- 1 file changed, 60 insertions(+), 33 deletions(-) diff -puN kernel/cpuset.c~cpuset-dont-allocate-trial-cpuset-on-stack kernel/cpuset.c --- a/kernel/cpuset.c~cpuset-dont-allocate-trial-cpuset-on-stack +++ a/kernel/cpuset.c @@ -415,6 +415,24 @@ static int is_cpuset_subset(const struct is_mem_exclusive(p) <= is_mem_exclusive(q); } +/** + * alloc_trial_cpuset - allocate a trial cpuset + * @cs: the cpuset that the trial cpuset duplicates + */ +static struct cpuset *alloc_trial_cpuset(const struct cpuset *cs) +{ + return kmemdup(cs, sizeof(*cs), GFP_KERNEL); +} + +/** + * free_trial_cpuset - free the trial cpuset + * @trial: the trial cpuset to be freed + */ +static void free_trial_cpuset(struct cpuset *trial) +{ + kfree(trial); +} + /* * validate_change() - Used to validate that any proposed cpuset change * follows the structural rules for cpusets. @@ -880,10 +898,10 @@ static void update_tasks_cpumask(struct * @cs: the cpuset to consider * @buf: buffer of cpu numbers written to this cpuset */ -static int update_cpumask(struct cpuset *cs, const char *buf) +static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, + const char *buf) { struct ptr_heap heap; - struct cpuset trialcs; int retval; int is_load_balanced; @@ -891,8 +909,6 @@ static int update_cpumask(struct cpuset if (cs == &top_cpuset) return -EACCES; - trialcs = *cs; - /* * An empty cpus_allowed is ok only if the cpuset has no tasks. * Since cpulist_parse() fails on an empty mask, we special case @@ -900,31 +916,31 @@ static int update_cpumask(struct cpuset * with tasks have cpus. */ if (!*buf) { - cpus_clear(trialcs.cpus_allowed); + cpus_clear(trialcs->cpus_allowed); } else { - retval = cpulist_parse(buf, &trialcs.cpus_allowed); + retval = cpulist_parse(buf, &trialcs->cpus_allowed); if (retval < 0) return retval; - if (!cpus_subset(trialcs.cpus_allowed, cpu_online_map)) + if (!cpus_subset(trialcs->cpus_allowed, cpu_online_map)) return -EINVAL; } - retval = validate_change(cs, &trialcs); + retval = validate_change(cs, trialcs); if (retval < 0) return retval; /* Nothing to do if the cpus didn't change */ - if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed)) + if (cpus_equal(cs->cpus_allowed, trialcs->cpus_allowed)) return 0; retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); if (retval) return retval; - is_load_balanced = is_sched_load_balance(&trialcs); + is_load_balanced = is_sched_load_balance(trialcs); mutex_lock(&callback_mutex); - cs->cpus_allowed = trialcs.cpus_allowed; + cs->cpus_allowed = trialcs->cpus_allowed; mutex_unlock(&callback_mutex); /* @@ -1099,9 +1115,9 @@ done: * lock each such tasks mm->mmap_sem, scan its vma's and rebind * their mempolicies to the cpusets new mems_allowed. */ -static int update_nodemask(struct cpuset *cs, const char *buf) +static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, + const char *buf) { - struct cpuset trialcs; nodemask_t oldmem; int retval; @@ -1112,8 +1128,6 @@ static int update_nodemask(struct cpuset if (cs == &top_cpuset) return -EACCES; - trialcs = *cs; - /* * An empty mems_allowed is ok iff there are no tasks in the cpuset. * Since nodelist_parse() fails on an empty mask, we special case @@ -1121,27 +1135,27 @@ static int update_nodemask(struct cpuset * with tasks have memory. */ if (!*buf) { - nodes_clear(trialcs.mems_allowed); + nodes_clear(trialcs->mems_allowed); } else { - retval = nodelist_parse(buf, trialcs.mems_allowed); + retval = nodelist_parse(buf, trialcs->mems_allowed); if (retval < 0) goto done; - if (!nodes_subset(trialcs.mems_allowed, + if (!nodes_subset(trialcs->mems_allowed, node_states[N_HIGH_MEMORY])) return -EINVAL; } oldmem = cs->mems_allowed; - if (nodes_equal(oldmem, trialcs.mems_allowed)) { + if (nodes_equal(oldmem, trialcs->mems_allowed)) { retval = 0; /* Too easy - nothing to do */ goto done; } - retval = validate_change(cs, &trialcs); + retval = validate_change(cs, trialcs); if (retval < 0) goto done; mutex_lock(&callback_mutex); - cs->mems_allowed = trialcs.mems_allowed; + cs->mems_allowed = trialcs->mems_allowed; cs->mems_generation = cpuset_mems_generation++; mutex_unlock(&callback_mutex); @@ -1181,31 +1195,36 @@ static int update_relax_domain_level(str static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, int turning_on) { - struct cpuset trialcs; + struct cpuset *trialcs; int err; int balance_flag_changed; - trialcs = *cs; + trialcs = alloc_trial_cpuset(cs); + if (!trialcs) + return -ENOMEM; + if (turning_on) - set_bit(bit, &trialcs.flags); + set_bit(bit, &trialcs->flags); else - clear_bit(bit, &trialcs.flags); + clear_bit(bit, &trialcs->flags); - err = validate_change(cs, &trialcs); + err = validate_change(cs, trialcs); if (err < 0) - return err; + goto out; balance_flag_changed = (is_sched_load_balance(cs) != - is_sched_load_balance(&trialcs)); + is_sched_load_balance(trialcs)); mutex_lock(&callback_mutex); - cs->flags = trialcs.flags; + cs->flags = trialcs->flags; mutex_unlock(&callback_mutex); - if (!cpus_empty(trialcs.cpus_allowed) && balance_flag_changed) + if (!cpus_empty(trialcs->cpus_allowed) && balance_flag_changed) async_rebuild_sched_domains(); - return 0; +out: + free_trial_cpuset(trialcs); + return err; } /* @@ -1471,21 +1490,29 @@ static int cpuset_write_resmask(struct c const char *buf) { int retval = 0; + struct cpuset *cs = cgroup_cs(cgrp); + struct cpuset *trialcs; if (!cgroup_lock_live_group(cgrp)) return -ENODEV; + trialcs = alloc_trial_cpuset(cs); + if (!trialcs) + return -ENOMEM; + switch (cft->private) { case FILE_CPULIST: - retval = update_cpumask(cgroup_cs(cgrp), buf); + retval = update_cpumask(cs, trialcs, buf); break; case FILE_MEMLIST: - retval = update_nodemask(cgroup_cs(cgrp), buf); + retval = update_nodemask(cs, trialcs, buf); break; default: retval = -EINVAL; break; } + + free_trial_cpuset(trialcs); cgroup_unlock(); return retval; } _ Patches currently in -mm which might be from lizf@xxxxxxxxxxxxxx are origin.patch vfs-factor-out-duplicated-code-in-get_fs_type.patch oom-print-triggering-tasks-cpuset-and-mems-allowed-fix.patch cgroups-documentation-updates.patch cgroups-remove-some-redundant-null-checks.patch ns_cgroup-remove-unused-spinlock.patch memcg-fix-a-typo-in-kconfig.patch cgroups-make-root_list-contains-active-hierarchies-only.patch cgroups-add-inactive-subsystems-to-rootnodesubsys_list.patch cgroups-add-inactive-subsystems-to-rootnodesubsys_list-fix.patch cgroups-introduce-link_css_set-to-remove-duplicate-code.patch cgroups-introduce-link_css_set-to-remove-duplicate-code-fix.patch cgroups-make-cgroup_path-rcu-safe.patch cgroups-make-cgroup_path-rcu-safe-fixlet.patch devices-cgroup-allow-mkfifo.patch memcg-reduce-size-of-mem_cgroup-by-using-nr_cpu_ids.patch memcg-new-force_empty-to-free-pages-under-group.patch memcg-new-force_empty-to-free-pages-under-group-fix.patch memcg-new-force_empty-to-free-pages-under-group-fix-fix.patch memcg-handle-swap-caches.patch memcg-memswap-controller-kconfig.patch memcg-swap-cgroup-for-remembering-usage.patch memcg-memswap-controller-core.patch memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch memcg-memswap-controller-core-swapcache-fixes.patch memcg-synchronized-lru.patch memcg-add-mem_cgroup_disabled.patch memcg-add-mem_cgroup_disabled-fix.patch memory-cgroup-hierarchy-documentation-v4.patch memory-cgroup-resource-counters-for-hierarchy-v4.patch memory-cgroup-resource-counters-for-hierarchy-v4-checkpatch-fixes.patch memory-cgroup-hierarchical-reclaim-v4.patch memory-cgroup-hierarchical-reclaim-v4-checkpatch-fixes.patch memory-cgroup-hierarchical-reclaim-v4-fix-for-hierarchical-reclaim.patch memory-cgroup-hierarchy-feature-selector-v4.patch memory-cgroup-hierarchy-feature-selector-v4-fix.patch memcg-avoid-unnecessary-system-wide-oom-killer.patch memcg-avoid-unnecessary-system-wide-oom-killer-fix.patch memcg-fix-reclaim-result-checks.patch memcg-swapout-refcnt-fix.patch memcg-fix-double-free-and-make-refcnt-sane.patch memcg-use-css_tryget-in-memcg.patch memcg-use-css_tryget-in-memcg-fix.patch memcg-fix-lru-accounting-for-swapcache-v2.patch memcg-fix-shmems-swap-accounting.patch cgroups-add-a-per-subsystem-hierarchy_mutex.patch cgroups-use-hierarchy_mutex-in-memory-controller.patch cgroups-add-css_tryget.patch cpuset-remove-on-stack-cpumask_t-in-cpuset_sprintf_cpulist.patch cpuset-remove-on-stack-cpumask_t-in-cpuset_can_attach.patch cpuset-convert-cpuset_attach-to-use-cpumask_var_t.patch cpuset-dont-allocate-trial-cpuset-on-stack.patch cpuset-convert-cpuset-cpus_allowed-to-cpumask_var_t.patch cpuset-remove-remaining-pointers-to-cpumask_t.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html