From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Yu Zhao <yuzhao@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
Ingo Molnar <mingo@kernel.org>, Hugh Dickins <hughd@google.com>,
Sasha Levin <sasha.levin@oracle.com>, Bob Liu <lliubbo@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] mm: free compound page with correct order
Date: Wed, 15 Oct 2014 23:05:01 +0300 [thread overview]
Message-ID: <20141015200501.GA17066@node.dhcp.inet.fi> (raw)
In-Reply-To: <20141015123044.03f38a520b01c5d332e3d9a5@linux-foundation.org>
On Wed, Oct 15, 2014 at 12:30:44PM -0700, Andrew Morton wrote:
> > @@ -232,7 +232,7 @@ static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
> > if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
> > struct page *zero_page = xchg(&huge_zero_page, NULL);
> > BUG_ON(zero_page == NULL);
> > - __free_page(zero_page);
> > + __free_pages(zero_page, compound_order(zero_page));
>
> But I'm surprised that this is also rare. It makes me wonder if this
> code is working correctly.
This should be rare too. To get here we need a situation when huge zero
page is allocated, but not mapped and we get memory presure to trigger
shrinker.
--
Kirill A. Shutemov
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WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Yu Zhao <yuzhao@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
Ingo Molnar <mingo@kernel.org>, Hugh Dickins <hughd@google.com>,
Sasha Levin <sasha.levin@oracle.com>, Bob Liu <lliubbo@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] mm: free compound page with correct order
Date: Wed, 15 Oct 2014 23:05:01 +0300 [thread overview]
Message-ID: <20141015200501.GA17066@node.dhcp.inet.fi> (raw)
In-Reply-To: <20141015123044.03f38a520b01c5d332e3d9a5@linux-foundation.org>
On Wed, Oct 15, 2014 at 12:30:44PM -0700, Andrew Morton wrote:
> > @@ -232,7 +232,7 @@ static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
> > if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
> > struct page *zero_page = xchg(&huge_zero_page, NULL);
> > BUG_ON(zero_page == NULL);
> > - __free_page(zero_page);
> > + __free_pages(zero_page, compound_order(zero_page));
>
> But I'm surprised that this is also rare. It makes me wonder if this
> code is working correctly.
This should be rare too. To get here we need a situation when huge zero
page is allocated, but not mapped and we get memory presure to trigger
shrinker.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2014-10-15 20:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-15 19:20 [PATCH v2 1/2] mm: free compound page with correct order Yu Zhao
2014-10-15 19:20 ` Yu Zhao
2014-10-15 19:20 ` [PATCH v2 2/2] mm: verify compound order when freeing a page Yu Zhao
2014-10-15 19:20 ` Yu Zhao
2014-10-15 20:07 ` Kirill A. Shutemov
2014-10-15 20:07 ` Kirill A. Shutemov
2014-10-15 19:30 ` [PATCH v2 1/2] mm: free compound page with correct order Andrew Morton
2014-10-15 19:30 ` Andrew Morton
2014-10-15 20:05 ` Kirill A. Shutemov [this message]
2014-10-15 20:05 ` Kirill A. Shutemov
2014-10-24 20:13 ` Yu Zhao
2014-10-24 20:13 ` Yu Zhao
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