From: Michal Hocko <mhocko@suse.cz>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>, Tejun Heo <tj@kernel.org>,
Vladimir Davydov <vdavydov@parallels.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 13/13] mm: memcontrol: rewrite uncharge API
Date: Tue, 15 Jul 2014 14:19:35 +0200 [thread overview]
Message-ID: <20140715121935.GB9366@dhcp22.suse.cz> (raw)
In-Reply-To: <20140715082545.GA9366@dhcp22.suse.cz>
[...]
> +/**
> + * mem_cgroup_migrate - migrate a charge to another page
> + * @oldpage: currently charged page
> + * @newpage: page to transfer the charge to
> + * @lrucare: page might be on LRU already
which one? I guess the newpage?
> + *
> + * Migrate the charge from @oldpage to @newpage.
> + *
> + * Both pages must be locked, @newpage->mapping must be set up.
> + */
> +void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
> + bool lrucare)
> +{
> + unsigned int nr_pages = 1;
> + struct page_cgroup *pc;
> +
> + VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
> + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
> + VM_BUG_ON_PAGE(PageLRU(oldpage), oldpage);
> + VM_BUG_ON_PAGE(PageLRU(newpage), newpage);
VM_BUG_ON_PAGE(PageLRU(newpage) && !lruvec, newpage);
> + VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
> +
> + if (mem_cgroup_disabled())
> + return;
> +
> + pc = lookup_page_cgroup(oldpage);
> + if (!PageCgroupUsed(pc))
> + return;
> +
> + /* Already migrated */
> + if (!(pc->flags & PCG_MEM))
> + return;
> +
> + VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage);
> + pc->flags &= ~(PCG_MEM | PCG_MEMSW);
What about PCG_USED?
Wouldn't we uncharge the currently transfered charge when oldpage does
its last put_page when the migration is done?
On a not directly related note. I was quite surprised to see that
__unmap_and_move calls putback_lru_page on oldpage even when migration
succeeded. So it goes through mem_cgroup_page_lruvec which checks
PCG_USED and resets pc->mem_cgroup to root for !PCG_USED.
> +
> + if (PageTransHuge(oldpage)) {
> + nr_pages <<= compound_order(oldpage);
> + VM_BUG_ON_PAGE(!PageTransHuge(oldpage), oldpage);
> + VM_BUG_ON_PAGE(!PageTransHuge(newpage), newpage);
> + }
> +
> + commit_charge(newpage, pc->mem_cgroup, nr_pages, lrucare);
> +}
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2014-07-15 12:19 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-18 20:40 [patch 00/13] mm: memcontrol: naturalize charge lifetime v4 Johannes Weiner
2014-06-18 20:40 ` [patch 01/13] mm: memcontrol: fold mem_cgroup_do_charge() Johannes Weiner
2014-06-18 20:40 ` [patch 02/13] mm: memcontrol: rearrange charging fast path Johannes Weiner
2014-06-18 20:40 ` [patch 03/13] mm: memcontrol: reclaim at least once for __GFP_NORETRY Johannes Weiner
2014-06-18 20:40 ` [patch 04/13] mm: huge_memory: use GFP_TRANSHUGE when charging huge pages Johannes Weiner
2014-06-18 20:40 ` [patch 05/13] mm: memcontrol: retry reclaim for oom-disabled and __GFP_NOFAIL charges Johannes Weiner
2014-06-18 20:40 ` [patch 06/13] mm: memcontrol: remove explicit OOM parameter in charge path Johannes Weiner
2014-06-18 20:40 ` [patch 07/13] mm: memcontrol: simplify move precharge function Johannes Weiner
2014-06-18 20:40 ` [patch 08/13] mm: memcontrol: catch root bypass in move precharge Johannes Weiner
2014-06-18 20:40 ` [patch 09/13] mm: memcontrol: use root_mem_cgroup res_counter Johannes Weiner
2014-06-18 20:40 ` [patch 10/13] mm: memcontrol: remove ordering between pc->mem_cgroup and PageCgroupUsed Johannes Weiner
2014-06-18 20:40 ` [patch 11/13] mm: memcontrol: do not acquire page_cgroup lock for kmem pages Johannes Weiner
2014-06-18 20:40 ` [patch 12/13] mm: memcontrol: rewrite charge API Johannes Weiner
2014-06-23 6:15 ` Uwe Kleine-König
2014-06-23 9:30 ` Michal Hocko
2014-06-23 9:42 ` Uwe Kleine-König
2014-07-14 15:04 ` Michal Hocko
2014-07-14 17:13 ` Johannes Weiner
2014-07-14 18:43 ` Michal Hocko
2014-06-18 20:40 ` [patch 13/13] mm: memcontrol: rewrite uncharge API Johannes Weiner
2014-06-20 16:36 ` [PATCH -mm] memcg: mem_cgroup_charge_statistics needs preempt_disable Michal Hocko
2014-06-23 4:16 ` Johannes Weiner
2014-06-21 0:34 ` [patch 13/13] mm: memcontrol: rewrite uncharge API Sasha Levin
2014-06-21 0:56 ` Andrew Morton
2014-06-21 1:03 ` Sasha Levin
2014-07-15 8:25 ` Michal Hocko
2014-07-15 12:19 ` Michal Hocko [this message]
2014-07-18 7:12 ` Michal Hocko
2014-07-18 14:45 ` Johannes Weiner
2014-07-18 15:12 ` Miklos Szeredi
2014-07-19 17:39 ` Johannes Weiner
2014-07-22 15:08 ` Michal Hocko
2014-07-22 15:44 ` Miklos Szeredi
2014-07-23 14:38 ` Michal Hocko
2014-07-23 15:06 ` Johannes Weiner
2014-07-23 15:19 ` Michal Hocko
2014-07-23 15:36 ` Johannes Weiner
2014-07-23 18:08 ` Miklos Szeredi
2014-07-23 21:02 ` Johannes Weiner
2014-07-24 8:46 ` Michal Hocko
2014-07-24 9:02 ` Michal Hocko
2014-07-25 15:26 ` Johannes Weiner
2014-07-25 15:43 ` Michal Hocko
2014-07-25 17:34 ` Johannes Weiner
2014-07-15 14:23 ` Michal Hocko
2014-07-15 15:09 ` Johannes Weiner
2014-07-15 15:18 ` Michal Hocko
2014-07-15 15:46 ` Johannes Weiner
2014-07-15 15:56 ` Michal Hocko
2014-07-15 15:55 ` Naoya Horiguchi
2014-07-15 16:07 ` Michal Hocko
2014-07-15 17:34 ` Johannes Weiner
2014-07-15 18:21 ` Michal Hocko
2014-07-15 18:43 ` Naoya Horiguchi
2014-07-15 19:04 ` Johannes Weiner
2014-07-15 20:49 ` Naoya Horiguchi
2014-07-15 21:48 ` Johannes Weiner
2014-07-16 7:55 ` Michal Hocko
2014-07-16 13:30 ` Naoya Horiguchi
2014-07-16 14:14 ` Johannes Weiner
2014-07-16 14:57 ` Naoya Horiguchi
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