From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Zi Yan <ziy@nvidia.com>
Cc: akpm@linux-foundation.org, Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 3/7] khugepaged: Drain LRU add pagevec to get rid of extra pins
Date: Sat, 28 Mar 2020 03:20:41 +0300 [thread overview]
Message-ID: <20200328002041.5tnoy67ruw7lavwx@box> (raw)
In-Reply-To: <D4EBA00D-BD65-4B7A-8C39-75DE43BD8CB8@nvidia.com>
On Fri, Mar 27, 2020 at 01:34:20PM -0400, Zi Yan wrote:
> On 27 Mar 2020, at 13:05, Kirill A. Shutemov wrote:
>
> > __collapse_huge_page_isolate() may fail due to extra pin in the LRU add
> > pagevec. It's petty common for swapin case: we swap in pages just to
> > fail due to the extra pin.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> > mm/khugepaged.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > index 14d7afc90786..39e0994abeb8 100644
> > --- a/mm/khugepaged.c
> > +++ b/mm/khugepaged.c
> > @@ -585,11 +585,19 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
> > * The page must only be referenced by the scanned process
> > * and page swap cache.
> > */
> > + if (page_count(page) != 1 + PageSwapCache(page)) {
> > + /*
> > + * Drain pagevec and retry just in case we can get rid
> > + * of the extra pin, like in swapin case.
> > + */
> > + lru_add_drain();
> > + }
> > if (page_count(page) != 1 + PageSwapCache(page)) {
> > unlock_page(page);
> > result = SCAN_PAGE_COUNT;
> > goto out;
> > }
> > +
> > if (pte_write(pteval)) {
> > writable = true;
> > } else {
> > --
> > 2.26.0
>
> Looks good to me. Is the added empty line intentional?
Yes. It groups try and retry together.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-03-28 0:20 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 17:05 [PATCH 0/7] thp/khugepaged improvements and CoW semantics Kirill A. Shutemov
2020-03-27 17:05 ` [PATCH 1/7] khugepaged: Add self test Kirill A. Shutemov
2020-03-27 17:05 ` [PATCH 2/7] khugepaged: Do not stop collapse if less than half PTEs are referenced Kirill A. Shutemov
2020-03-27 17:30 ` Zi Yan
2020-03-27 17:46 ` Yang Shi
2020-03-27 17:05 ` [PATCH 3/7] khugepaged: Drain LRU add pagevec to get rid of extra pins Kirill A. Shutemov
2020-03-27 17:34 ` Zi Yan
2020-03-28 0:20 ` Kirill A. Shutemov [this message]
2020-03-27 18:10 ` Yang Shi
2020-03-28 12:18 ` Kirill A. Shutemov
2020-03-30 18:30 ` Yang Shi
2020-03-30 21:38 ` Kirill A. Shutemov
2020-03-27 17:05 ` [PATCH 4/7] khugepaged: Allow to callapse a page shared across fork Kirill A. Shutemov
2020-03-27 18:19 ` Zi Yan
2020-03-27 21:31 ` Yang Shi
2020-03-27 21:44 ` Zi Yan
2020-03-27 17:05 ` [PATCH 5/7] khugepaged: Allow to collapse PTE-mapped compound pages Kirill A. Shutemov
2020-03-27 18:53 ` Yang Shi
2020-03-28 0:34 ` Kirill A. Shutemov
2020-03-28 1:09 ` Yang Shi
2020-03-28 12:27 ` Kirill A. Shutemov
2020-03-30 18:38 ` Yang Shi
2020-03-27 18:55 ` Zi Yan
2020-03-28 0:39 ` Kirill A. Shutemov
2020-03-28 1:17 ` Zi Yan
2020-03-28 12:33 ` Kirill A. Shutemov
2020-03-30 18:41 ` Yang Shi
2020-03-30 18:50 ` Yang Shi
2020-03-31 14:08 ` Kirill A. Shutemov
2020-04-01 19:45 ` Yang Shi
2020-03-27 20:45 ` Yang Shi
2020-03-28 0:40 ` Kirill A. Shutemov
2020-03-28 1:12 ` Yang Shi
2020-03-27 17:06 ` [PATCH 6/7] thp: Change CoW semantics for anon-THP Kirill A. Shutemov
2020-03-27 20:07 ` Yang Shi
2020-03-28 0:43 ` Kirill A. Shutemov
2020-03-28 1:30 ` Yang Shi
2020-03-27 17:06 ` [PATCH 7/7] khugepaged: Introduce 'max_ptes_shared' tunable Kirill A. Shutemov
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