From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>,
Dave Hansen <dave.hansen@intel.com>, Mel Gorman <mgorman@suse.de>,
Rik van Riel <riel@redhat.com>, Christoph Lameter <cl@gentwo.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Steve Capper <steve.capper@linaro.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
Jerome Marchand <jmarchan@redhat.com>,
Sasha Levin <sasha.levin@oracle.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv6 33/36] migrate_pages: try to split pages on qeueuing
Date: Mon, 22 Jun 2015 14:35:25 +0300 [thread overview]
Message-ID: <20150622113525.GE7934@node.dhcp.inet.fi> (raw)
In-Reply-To: <55795477.90808@suse.cz>
On Thu, Jun 11, 2015 at 11:27:19AM +0200, Vlastimil Babka wrote:
> On 06/03/2015 07:06 PM, Kirill A. Shutemov wrote:
> >We are not able to migrate THPs. It means it's not enough to split only
> >PMD on migration -- we need to split compound page under it too.
> >
> >Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> >---
> > mm/mempolicy.c | 37 +++++++++++++++++++++++++++++++++----
> > 1 file changed, 33 insertions(+), 4 deletions(-)
> >
> >diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> >index 528f6c467cf1..0b1499c2f890 100644
> >--- a/mm/mempolicy.c
> >+++ b/mm/mempolicy.c
> >@@ -489,14 +489,31 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
> > struct page *page;
> > struct queue_pages *qp = walk->private;
> > unsigned long flags = qp->flags;
> >- int nid;
> >+ int nid, ret;
> > pte_t *pte;
> > spinlock_t *ptl;
> >
> >- split_huge_pmd(vma, pmd, addr);
> >- if (pmd_trans_unstable(pmd))
> >- return 0;
> >+ if (pmd_trans_huge(*pmd)) {
> >+ ptl = pmd_lock(walk->mm, pmd);
> >+ if (pmd_trans_huge(*pmd)) {
> >+ page = pmd_page(*pmd);
> >+ if (is_huge_zero_page(page)) {
> >+ spin_unlock(ptl);
> >+ split_huge_pmd(vma, pmd, addr);
> >+ } else {
> >+ get_page(page);
> >+ spin_unlock(ptl);
> >+ lock_page(page);
> >+ ret = split_huge_page(page);
> >+ unlock_page(page);
> >+ put_page(page);
> >+ if (ret)
> >+ return 0;
> >+ }
> >+ }
> >+ }
> >
> >+retry:
> > pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
> > for (; addr != end; pte++, addr += PAGE_SIZE) {
> > if (!pte_present(*pte))
> >@@ -513,6 +530,18 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
> > nid = page_to_nid(page);
> > if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
> > continue;
> >+ if (PageTail(page) && PageAnon(page)) {
>
> Hm, can it really happen that we stumble upon THP tail page here, without
> first stumbling upon it in the previous hunk above? If so, when?
The first hunk catch PMD-mapped THP and here we deal with PTE-mapped.
The scenario: fault in a THP, split PMD (not page) e.g. with mprotect()
and then try to migrate.
--
Kirill A. Shutemov
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>,
Dave Hansen <dave.hansen@intel.com>, Mel Gorman <mgorman@suse.de>,
Rik van Riel <riel@redhat.com>, Christoph Lameter <cl@gentwo.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Steve Capper <steve.capper@linaro.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
Jerome Marchand <jmarchan@redhat.com>,
Sasha Levin <sasha.levin@oracle.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv6 33/36] migrate_pages: try to split pages on qeueuing
Date: Mon, 22 Jun 2015 14:35:25 +0300 [thread overview]
Message-ID: <20150622113525.GE7934@node.dhcp.inet.fi> (raw)
In-Reply-To: <55795477.90808@suse.cz>
On Thu, Jun 11, 2015 at 11:27:19AM +0200, Vlastimil Babka wrote:
> On 06/03/2015 07:06 PM, Kirill A. Shutemov wrote:
> >We are not able to migrate THPs. It means it's not enough to split only
> >PMD on migration -- we need to split compound page under it too.
> >
> >Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> >---
> > mm/mempolicy.c | 37 +++++++++++++++++++++++++++++++++----
> > 1 file changed, 33 insertions(+), 4 deletions(-)
> >
> >diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> >index 528f6c467cf1..0b1499c2f890 100644
> >--- a/mm/mempolicy.c
> >+++ b/mm/mempolicy.c
> >@@ -489,14 +489,31 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
> > struct page *page;
> > struct queue_pages *qp = walk->private;
> > unsigned long flags = qp->flags;
> >- int nid;
> >+ int nid, ret;
> > pte_t *pte;
> > spinlock_t *ptl;
> >
> >- split_huge_pmd(vma, pmd, addr);
> >- if (pmd_trans_unstable(pmd))
> >- return 0;
> >+ if (pmd_trans_huge(*pmd)) {
> >+ ptl = pmd_lock(walk->mm, pmd);
> >+ if (pmd_trans_huge(*pmd)) {
> >+ page = pmd_page(*pmd);
> >+ if (is_huge_zero_page(page)) {
> >+ spin_unlock(ptl);
> >+ split_huge_pmd(vma, pmd, addr);
> >+ } else {
> >+ get_page(page);
> >+ spin_unlock(ptl);
> >+ lock_page(page);
> >+ ret = split_huge_page(page);
> >+ unlock_page(page);
> >+ put_page(page);
> >+ if (ret)
> >+ return 0;
> >+ }
> >+ }
> >+ }
> >
> >+retry:
> > pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
> > for (; addr != end; pte++, addr += PAGE_SIZE) {
> > if (!pte_present(*pte))
> >@@ -513,6 +530,18 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
> > nid = page_to_nid(page);
> > if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
> > continue;
> >+ if (PageTail(page) && PageAnon(page)) {
>
> Hm, can it really happen that we stumble upon THP tail page here, without
> first stumbling upon it in the previous hunk above? If so, when?
The first hunk catch PMD-mapped THP and here we deal with PTE-mapped.
The scenario: fault in a THP, split PMD (not page) e.g. with mprotect()
and then try to migrate.
--
Kirill A. Shutemov
--
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next prev parent reply other threads:[~2015-06-22 11:35 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-03 17:05 [PATCHv6 00/36] THP refcounting redesign Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 01/36] mm, proc: adjust PSS calculation Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-09 12:29 ` Vlastimil Babka
2015-06-09 12:29 ` Vlastimil Babka
2015-06-22 10:02 ` Kirill A. Shutemov
2015-06-22 10:02 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 02/36] rmap: add argument to charge compound page Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 03/36] memcg: adjust to support new THP refcounting Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 04/36] mm, thp: adjust conditions when we can reuse the page on WP fault Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 05/36] mm: adjust FOLL_SPLIT for new refcounting Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 06/36] mm: handle PTE-mapped tail pages in gerneric fast gup implementaiton Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 07/36] thp, mlock: do not allow huge pages in mlocked area Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 08/36] khugepaged: ignore pmd tables with THP mapped with ptes Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 09/36] thp: rename split_huge_page_pmd() to split_huge_pmd() Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 10/36] mm, vmstats: new THP splitting event Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 11/36] mm: temporally mark THP broken Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 12/36] thp: drop all split_huge_page()-related code Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 13/36] mm: drop tail page refcounting Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-09 13:59 ` Vlastimil Babka
2015-06-09 13:59 ` Vlastimil Babka
2015-06-03 17:05 ` [PATCHv6 14/36] futex, thp: remove special case for THP in get_futex_key Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 15/36] ksm: prepare to new THP semantics Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 16/36] mm, thp: remove compound_lock Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 17/36] arm64, thp: remove infrastructure for handling splitting PMDs Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 18/36] arm, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 19/36] mips, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 20/36] powerpc, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 21/36] s390, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 22/36] sparc, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 23/36] tile, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 24/36] x86, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 25/36] mm, " Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 26/36] mm: rework mapcount accounting to enable 4k mapping of THPs Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-10 13:47 ` Vlastimil Babka
2015-06-10 13:47 ` Vlastimil Babka
2015-06-22 10:22 ` Kirill A. Shutemov
2015-06-22 10:22 ` Kirill A. Shutemov
2015-06-03 17:05 ` [PATCHv6 27/36] mm: differentiate page_mapped() from page_mapcount() for compound pages Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-09 10:58 ` Kirill A. Shutemov
2015-06-09 10:58 ` Kirill A. Shutemov
2015-06-10 14:34 ` Vlastimil Babka
2015-06-10 14:34 ` Vlastimil Babka
2015-06-03 17:05 ` [PATCHv6 28/36] mm, numa: skip PTE-mapped THP on numa fault Kirill A. Shutemov
2015-06-03 17:05 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 29/36] thp: implement split_huge_pmd() Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-11 9:49 ` Vlastimil Babka
2015-06-11 9:49 ` Vlastimil Babka
2015-06-22 11:14 ` Kirill A. Shutemov
2015-06-22 11:14 ` Kirill A. Shutemov
2015-06-22 16:01 ` Vlastimil Babka
2015-06-22 16:01 ` Vlastimil Babka
2015-06-03 17:06 ` [PATCHv6 30/36] thp: add option to setup migration entiries during PMD split Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 31/36] thp, mm: split_huge_page(): caller need to lock page Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 32/36] thp: reintroduce split_huge_page() Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-10 15:44 ` Vlastimil Babka
2015-06-10 15:44 ` Vlastimil Babka
2015-06-22 11:28 ` Kirill A. Shutemov
2015-06-22 11:28 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 33/36] migrate_pages: try to split pages on qeueuing Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-11 9:27 ` Vlastimil Babka
2015-06-11 9:27 ` Vlastimil Babka
2015-06-22 11:35 ` Kirill A. Shutemov [this message]
2015-06-22 11:35 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 34/36] thp: introduce deferred_split_huge_page() Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 35/36] mm: re-enable THP Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-03 17:06 ` [PATCHv6 36/36] thp: update documentation Kirill A. Shutemov
2015-06-03 17:06 ` Kirill A. Shutemov
2015-06-11 12:30 ` Vlastimil Babka
2015-06-11 12:30 ` Vlastimil Babka
2015-06-22 13:18 ` Kirill A. Shutemov
2015-06-22 13:18 ` Kirill A. Shutemov
2015-06-22 16:07 ` Vlastimil Babka
2015-06-22 16:07 ` Vlastimil Babka
2015-06-16 13:17 ` [PATCHv6 00/36] THP refcounting redesign Jerome Marchand
2015-06-22 13:21 ` Kirill A. Shutemov
2015-06-22 13:21 ` Kirill A. Shutemov
2015-06-22 13:32 ` Jerome Marchand
2015-06-22 13:39 ` Kirill A. Shutemov
2015-06-22 13:39 ` Kirill A. Shutemov
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