| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20090615172021.ab1a8a7a.kamezawa.hiroyu@jp.fujitsu.com>
Date: Mon, 15 Jun 2009 17:20:21 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To: balbir@...ux.vnet.ibm.com
Cc: Andrew Morton <akpm@...ux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyuki@...fujitsu.com>,
"nishimura@....nes.nec.co.jp" <nishimura@....nes.nec.co.jp>,
"lizf@...fujitsu.com" <lizf@...fujitsu.com>,
"menage@...gle.com" <menage@...gle.com>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Low overhead patches for the memory cgroup controller (v5)
On Mon, 15 Jun 2009 10:09:00 +0530
Balbir Singh <balbir@...ux.vnet.ibm.com> wrote:
>
> Feature: Remove the overhead associated with the root cgroup
>
> From: Balbir Singh <balbir@...ux.vnet.ibm.com>
>
> Changelog v5 -> v4
> 1. Moved back to v3 logic (Daisuke and Kamezawa like that better)
> 2. Incorporated changes from Daisuke (remove list_empty() checks)
> 3. Updated documentation to reflect that limits cannot be set on root
> cgroup
>
> Changelog v4 -> v3
> 1. Rebase to mmotm 9th june 2009
> 2. Remove PageCgroupRoot, we have account LRU flags to indicate that
> we do only accounting and no reclaim.
> 3. pcg_default_flags has been used again, since PCGF_ROOT is gone,
> we set PCGF_ACCT_LRU only in mem_cgroup_add_lru_list
> 4. More LRU functions are aware of PageCgroupAcctLRU
>
> Changelog v3 -> v2
>
> 1. Rebase to mmotm 2nd June 2009
> 2. Test with some of the test cases recommended by Daisuke-San
>
> Changelog v2 -> v1
> 1. Rebase to latest mmotm
>
> This patch changes the memory cgroup and removes the overhead associated
> with accounting all pages in the root cgroup. As a side-effect, we can
> no longer set a memory hard limit in the root cgroup.
>
> A new flag to track whether the page has been accounted or not
> has been added as well. Flags are now set atomically for page_cgroup,
> pcg_default_flags is now obsolete and removed.
>
> Signed-off-by: Balbir Singh <balbir@...ux.vnet.ibm.com>
> Signed-off-by: Daisuke Nishimura <nishimura@....nes.nec.co.jp>
Seems fine.
Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
But we'll have to do heavy test whether we see BUG_ON or not..
Regards,
-Kame
> ---
>
> Documentation/cgroups/memory.txt | 4 +++
> include/linux/page_cgroup.h | 13 +++++++++
> mm/memcontrol.c | 54 ++++++++++++++++++++++++++++----------
> 3 files changed, 57 insertions(+), 14 deletions(-)
>
>
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index 23d1262..9ce27c6 100644
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -179,6 +179,9 @@ The reclaim algorithm has not been modified for cgroups, except that
> pages that are selected for reclaiming come from the per cgroup LRU
> list.
>
> +NOTE: Reclaim does not works for the root cgroup, since we cannot
> +set any limits on the root cgroup
> +
> 2. Locking
>
> The memory controller uses the following hierarchy
> @@ -210,6 +213,7 @@ We can alter the memory limit:
> NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo,
> mega or gigabytes.
> NOTE: We can write "-1" to reset the *.limit_in_bytes(unlimited).
> +NOTE: We cannot set limits on the root cgroup anymore.
>
> # cat /cgroups/0/memory.limit_in_bytes
> 4194304
> diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
> index 7339c7b..debd8ba 100644
> --- a/include/linux/page_cgroup.h
> +++ b/include/linux/page_cgroup.h
> @@ -26,6 +26,7 @@ enum {
> PCG_LOCK, /* page cgroup is locked */
> PCG_CACHE, /* charged as cache */
> PCG_USED, /* this object is in use. */
> + PCG_ACCT_LRU, /* page has been accounted for */
> };
>
> #define TESTPCGFLAG(uname, lname) \
> @@ -40,11 +41,23 @@ static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
> static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \
> { clear_bit(PCG_##lname, &pc->flags); }
>
> +#define TESTCLEARPCGFLAG(uname, lname) \
> +static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \
> + { return test_and_clear_bit(PCG_##lname, &pc->flags); }
> +
> /* Cache flag is set only once (at allocation) */
> TESTPCGFLAG(Cache, CACHE)
> +CLEARPCGFLAG(Cache, CACHE)
> +SETPCGFLAG(Cache, CACHE)
>
> TESTPCGFLAG(Used, USED)
> CLEARPCGFLAG(Used, USED)
> +SETPCGFLAG(Used, USED)
> +
> +SETPCGFLAG(AcctLRU, ACCT_LRU)
> +CLEARPCGFLAG(AcctLRU, ACCT_LRU)
> +TESTPCGFLAG(AcctLRU, ACCT_LRU)
> +TESTCLEARPCGFLAG(AcctLRU, ACCT_LRU)
>
> static inline int page_cgroup_nid(struct page_cgroup *pc)
> {
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6ceb6f2..bcbbd89 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -43,6 +43,7 @@
>
> struct cgroup_subsys mem_cgroup_subsys __read_mostly;
> #define MEM_CGROUP_RECLAIM_RETRIES 5
> +struct mem_cgroup *root_mem_cgroup __read_mostly;
>
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
> @@ -200,13 +201,8 @@ enum charge_type {
> #define PCGF_CACHE (1UL << PCG_CACHE)
> #define PCGF_USED (1UL << PCG_USED)
> #define PCGF_LOCK (1UL << PCG_LOCK)
> -static const unsigned long
> -pcg_default_flags[NR_CHARGE_TYPE] = {
> - PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
> - PCGF_USED | PCGF_LOCK, /* Anon */
> - PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
> - 0, /* FORCE */
> -};
> +/* Not used, but added here for completeness */
> +#define PCGF_ACCT (1UL << PCG_ACCT)
>
> /* for encoding cft->private value on file */
> #define _MEM (0)
> @@ -354,6 +350,11 @@ static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
> return ret;
> }
>
> +static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
> +{
> + return (mem == root_mem_cgroup);
> +}
> +
> /*
> * Following LRU functions are allowed to be used without PCG_LOCK.
> * Operations are called by routine of global LRU independently from memcg.
> @@ -371,22 +372,24 @@ static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
> void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
> {
> struct page_cgroup *pc;
> - struct mem_cgroup *mem;
> struct mem_cgroup_per_zone *mz;
>
> if (mem_cgroup_disabled())
> return;
> pc = lookup_page_cgroup(page);
> /* can happen while we handle swapcache. */
> - if (list_empty(&pc->lru) || !pc->mem_cgroup)
> + if (!TestClearPageCgroupAcctLRU(pc))
> return;
> + VM_BUG_ON(!pc->mem_cgroup);
> /*
> * We don't check PCG_USED bit. It's cleared when the "page" is finally
> * removed from global LRU.
> */
> mz = page_cgroup_zoneinfo(pc);
> - mem = pc->mem_cgroup;
> MEM_CGROUP_ZSTAT(mz, lru) -= 1;
> + if (mem_cgroup_is_root(pc->mem_cgroup))
> + return;
> + VM_BUG_ON(list_empty(&pc->lru));
> list_del_init(&pc->lru);
> return;
> }
> @@ -410,8 +413,8 @@ void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
> * For making pc->mem_cgroup visible, insert smp_rmb() here.
> */
> smp_rmb();
> - /* unused page is not rotated. */
> - if (!PageCgroupUsed(pc))
> + /* unused or root page is not rotated. */
> + if (!PageCgroupUsed(pc) || PageCgroupAcctLRU(pc))
> return;
> mz = page_cgroup_zoneinfo(pc);
> list_move(&pc->lru, &mz->lists[lru]);
> @@ -425,6 +428,7 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
> if (mem_cgroup_disabled())
> return;
> pc = lookup_page_cgroup(page);
> + VM_BUG_ON(PageCgroupAcctLRU(pc));
> /*
> * Used bit is set without atomic ops but after smp_wmb().
> * For making pc->mem_cgroup visible, insert smp_rmb() here.
> @@ -435,6 +439,9 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
>
> mz = page_cgroup_zoneinfo(pc);
> MEM_CGROUP_ZSTAT(mz, lru) += 1;
> + SetPageCgroupAcctLRU(pc);
> + if (mem_cgroup_is_root(pc->mem_cgroup))
> + return;
> list_add(&pc->lru, &mz->lists[lru]);
> }
>
> @@ -469,7 +476,7 @@ static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
>
> spin_lock_irqsave(&zone->lru_lock, flags);
> /* link when the page is linked to LRU but page_cgroup isn't */
> - if (PageLRU(page) && list_empty(&pc->lru))
> + if (PageLRU(page) && !PageCgroupAcctLRU(pc))
> mem_cgroup_add_lru_list(page, page_lru(page));
> spin_unlock_irqrestore(&zone->lru_lock, flags);
> }
> @@ -1114,9 +1121,22 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
> css_put(&mem->css);
> return;
> }
> +
> pc->mem_cgroup = mem;
> smp_wmb();
> - pc->flags = pcg_default_flags[ctype];
> + switch (ctype) {
> + case MEM_CGROUP_CHARGE_TYPE_CACHE:
> + case MEM_CGROUP_CHARGE_TYPE_SHMEM:
> + SetPageCgroupCache(pc);
> + SetPageCgroupUsed(pc);
> + break;
> + case MEM_CGROUP_CHARGE_TYPE_MAPPED:
> + ClearPageCgroupCache(pc);
> + SetPageCgroupUsed(pc);
> + break;
> + default:
> + break;
> + }
>
> mem_cgroup_charge_statistics(mem, pc, true);
>
> @@ -2055,6 +2075,10 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
> name = MEMFILE_ATTR(cft->private);
> switch (name) {
> case RES_LIMIT:
> + if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
> + ret = -EINVAL;
> + break;
> + }
> /* This function does all necessary parse...reuse it */
> ret = res_counter_memparse_write_strategy(buffer, &val);
> if (ret)
> @@ -2521,6 +2545,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
> if (cont->parent == NULL) {
> enable_swap_cgroup();
> parent = NULL;
> + root_mem_cgroup = mem;
> } else {
> parent = mem_cgroup_from_cont(cont->parent);
> mem->use_hierarchy = parent->use_hierarchy;
> @@ -2549,6 +2574,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
> return &mem->css;
> free_out:
> __mem_cgroup_free(mem);
> + root_mem_cgroup = NULL;
> return ERR_PTR(error);
> }
>
>
> --
> Balbir
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@...ck.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists