From: TSUKADA Koutaro <tsukada@ascade.co.jp>
To: Punit Agrawal <punit.agrawal@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
"Luis R. Rodriguez" <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Roman Gushchin <guro@fb.com>,
David Rientjes <rientjes@google.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
Marc-Andre Lureau <marcandre.lureau@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
cgroups@vger.kernel.org
Subject: Re: [PATCH v2 3/7] memcg: use compound_order rather than hpage_nr_pages
Date: Mon, 21 May 2018 12:48:22 +0900 [thread overview]
Message-ID: <2053ac36-74df-b05e-d1ce-36f69dde2a47@ascade.co.jp> (raw)
In-Reply-To: <87sh6ozwc4.fsf@e105922-lin.cambridge.arm.com>
On 2018/05/19 2:51, Punit Agrawal wrote:
> Punit Agrawal <punit.agrawal@arm.com> writes:
>
>> Tsukada-san,
>>
>> I am not familiar with memcg so can't comment about whether the patchset
>> is the right way to solve the problem outlined in the cover letter but
>> had a couple of comments about this patch.
>>
>> TSUKADA Koutaro <tsukada@ascade.co.jp> writes:
>>
>>> The current memcg implementation assumes that the compound page is THP.
>>> In order to be able to charge surplus hugepage, we use compound_order.
>>>
>>> Signed-off-by: TSUKADA Koutaro <tsukada@ascade.co.jp>
>>
>> Please move this before Patch 1/7. This is to prevent wrong accounting
>> of pages to memcg for size != PMD_SIZE.
>
> I just noticed that the default state is off so the change isn't enabled
> until the sysfs node is exposed in the next patch. Please ignore this
> comment.
>
> One below still applies.
>
>>
>>> ---
>>> memcontrol.c | 10 +++++-----
>>> 1 file changed, 5 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>>> index 2bd3df3..a8f1ff8 100644
>>> --- a/mm/memcontrol.c
>>> +++ b/mm/memcontrol.c
>>> @@ -4483,7 +4483,7 @@ static int mem_cgroup_move_account(struct page *page,
>>> struct mem_cgroup *to)
>>> {
>>> unsigned long flags;
>>> - unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
>>> + unsigned int nr_pages = compound ? (1 << compound_order(page)) : 1;
>>
>> Instead of replacing calls to hpage_nr_pages(), is it possible to modify
>> it to do the calculation?
Thank you for review my code and please just call me Tsukada.
I think it is possible to modify the inside of itself rather than
replacing the call to hpage_nr_pages().
Inferring from the processing that hpage_nr_pages() desires, I thought
that the definition of hpage_nr_pages() could be moved outside the
CONFIG_TRANSPARENT_HUGEPAGE. It seems that THP and HugeTLBfs can be
handled correctly because compound_order() is judged by seeing whether it
is PageHead or not.
Also, I would like to use compound_order() inside hpage_nr_pages(), but
since huge_mm.h is included before mm.h where compound_order() is defined,
move hpage_nr_pages to mm.h.
Instead of patch 3/7, are the following patches implementing what you
intended?
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a8a1262..1186ab7 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -204,12 +204,6 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
else
return NULL;
}
-static inline int hpage_nr_pages(struct page *page)
-{
- if (unlikely(PageTransHuge(page)))
- return HPAGE_PMD_NR;
- return 1;
-}
struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, int flags);
@@ -254,8 +248,6 @@ static inline bool thp_migration_supported(void)
#define HPAGE_PUD_MASK ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_SIZE ({ BUILD_BUG(); 0; })
-#define hpage_nr_pages(x) 1
-
static inline bool transparent_hugepage_enabled(struct vm_area_struct *vma)
{
return false;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1ac1f06..082f2ee 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -673,6 +673,12 @@ static inline unsigned int compound_order(struct page *page)
return page[1].compound_order;
}
+static inline int hpage_nr_pages(struct page *page)
+{
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ return (1 << compound_order(page));
+}
+
static inline void set_compound_order(struct page *page, unsigned int order)
{
page[1].compound_order = order;
--
Thanks,
Tsukada
next prev parent reply other threads:[~2018-05-21 3:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 4:27 [PATCH v2 0/7] mm: pages for hugetlb's overcommit may be able to charge to memcg TSUKADA Koutaro
2018-05-18 4:29 ` [PATCH v2 1/7] hugetlb: introduce charge_surplus_huge_pages to struct hstate TSUKADA Koutaro
2018-05-18 4:32 ` [PATCH v2 2/7] hugetlb: support migrate charging for surplus hugepages TSUKADA Koutaro
2018-05-18 4:34 ` [PATCH v2 3/7] memcg: use compound_order rather than hpage_nr_pages TSUKADA Koutaro
2018-05-18 17:46 ` Punit Agrawal
2018-05-18 17:51 ` Punit Agrawal
2018-05-21 3:48 ` TSUKADA Koutaro [this message]
2018-05-21 14:53 ` Punit Agrawal
2018-05-18 4:36 ` [PATCH v2 4/7] mm, sysctl: make charging surplus hugepages controllable TSUKADA Koutaro
2018-05-18 4:37 ` [PATCH v2 5/7] hugetlb: add charge_surplus_hugepages attribute TSUKADA Koutaro
2018-05-18 4:39 ` [PATCH v2 6/7] Documentation, hugetlb: describe about charge_surplus_hugepages, TSUKADA Koutaro
2018-05-18 4:41 ` [PATCH v2 7/7] memcg: supports movement of surplus hugepages statistics TSUKADA Koutaro
2018-05-21 14:52 ` [PATCH v2 0/7] mm: pages for hugetlb's overcommit may be able to charge to memcg Punit Agrawal
2018-05-22 12:56 ` TSUKADA Koutaro
2018-05-21 18:07 ` Mike Kravetz
2018-05-22 13:04 ` TSUKADA Koutaro
2018-05-22 18:54 ` Michal Hocko
2018-05-24 4:39 ` TSUKADA Koutaro
2018-05-24 8:20 ` Michal Hocko
2018-05-24 12:58 ` TSUKADA Koutaro
2018-05-24 13:24 ` Michal Hocko
2018-05-25 1:51 ` TSUKADA Koutaro
2018-05-22 20:28 ` Mike Kravetz
2018-05-22 13:51 ` Michal Hocko
2018-05-24 4:26 ` TSUKADA Koutaro
2018-05-24 8:27 ` Michal Hocko
2018-05-24 17:45 ` Mike Kravetz
2018-05-25 1:55 ` TSUKADA Koutaro
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2053ac36-74df-b05e-d1ce-36f69dde2a47@ascade.co.jp \
--to=tsukada@ascade.co.jp \
--cc=akpm@linux-foundation.org \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=cgroups@vger.kernel.org \
--cc=corbet@lwn.net \
--cc=dan.j.williams@intel.com \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=keescook@chromium.org \
--cc=khandual@linux.vnet.ibm.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=marcandre.lureau@redhat.com \
--cc=mcgrof@kernel.org \
--cc=mhocko@kernel.org \
--cc=mike.kravetz@oracle.com \
--cc=n-horiguchi@ah.jp.nec.com \
--cc=punit.agrawal@arm.com \
--cc=rientjes@google.com \
--cc=vbabka@suse.cz \
--cc=vdavydov.dev@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).