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Date: Thu, 5 Nov 2015 08:40:55 +0900
From: Minchan Kim <minchan@kernel.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Michael Kerrisk <mtk.manpages@gmail.com>,
        linux-api@vger.kernel.org, Hugh Dickins <hughd@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>, Rik van Riel <riel@redhat.com>,
        Mel Gorman <mgorman@suse.de>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Jason Evans <je@fb.com>, Daniel Micay <danielmicay@gmail.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Shaohua Li <shli@kernel.org>, Michal Hocko <mhocko@suse.cz>,
        yalin.wang2010@gmail.com
Subject: Re: [PATCH v2 01/13] mm: support madvise(MADV_FREE)
Message-ID: <20151104234055.GB7357@bbox>
References: <1446600367-7976-1-git-send-email-minchan@kernel.org>
 <1446600367-7976-2-git-send-email-minchan@kernel.org>
 <20151104022951.GA3744@swordfish>
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On Wed, Nov 04, 2015 at 11:29:51AM +0900, Sergey Senozhatsky wrote:
> On (11/04/15 10:25), Minchan Kim wrote:
> [..]
> > +static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
> > +				unsigned long end, struct mm_walk *walk)
> > +
> > +{
> > +	struct mmu_gather *tlb = walk->private;
> > +	struct mm_struct *mm = tlb->mm;
> > +	struct vm_area_struct *vma = walk->vma;
> > +	spinlock_t *ptl;
> > +	pte_t *pte, ptent;
> > +	struct page *page;
> 
> 
> I'll just ask (probably I'm missing something)
> 
> 	+ pmd_trans_huge_lock() ?

No. It would be deadlock.

> 
> > +	split_huge_page_pmd(vma, addr, pmd);
> > +	if (pmd_trans_unstable(pmd))
> > +		return 0;
> > +
> > +	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
> > +	arch_enter_lazy_mmu_mode();
> > +	for (; addr != end; pte++, addr += PAGE_SIZE) {
> > +		ptent = *pte;
> > +
> > +		if (!pte_present(ptent))
> > +			continue;
> > +
> > +		page = vm_normal_page(vma, addr, ptent);
> > +		if (!page)
> > +			continue;
> > +
> 
> 	-ss
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

From mboxrd@z Thu Jan  1 00:00:00 1970
From: Minchan Kim <minchan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH v2 01/13] mm: support madvise(MADV_FREE)
Date: Thu, 5 Nov 2015 08:40:55 +0900
Message-ID: <20151104234055.GB7357@bbox>
References: <1446600367-7976-1-git-send-email-minchan@kernel.org>
 <1446600367-7976-2-git-send-email-minchan@kernel.org>
 <20151104022951.GA3744@swordfish>
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Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Michael Kerrisk <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Mel Gorman <mgorman-l3A5Bk7waGM@public.gmane.org>, KOSAKI Motohiro <kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org>, Jason Evans <je-b10kYP2dOMg@public.gmane.org>, Daniel Micay <danielmicay-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, "Kirill A. Shutemov" <kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>, Shaohua Li <shli-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, yalin.wang2010-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
List-Id: linux-api@vger.kernel.org

On Wed, Nov 04, 2015 at 11:29:51AM +0900, Sergey Senozhatsky wrote:
> On (11/04/15 10:25), Minchan Kim wrote:
> [..]
> > +static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
> > +				unsigned long end, struct mm_walk *walk)
> > +
> > +{
> > +	struct mmu_gather *tlb = walk->private;
> > +	struct mm_struct *mm = tlb->mm;
> > +	struct vm_area_struct *vma = walk->vma;
> > +	spinlock_t *ptl;
> > +	pte_t *pte, ptent;
> > +	struct page *page;
> 
> 
> I'll just ask (probably I'm missing something)
> 
> 	+ pmd_trans_huge_lock() ?

No. It would be deadlock.

> 
> > +	split_huge_page_pmd(vma, addr, pmd);
> > +	if (pmd_trans_unstable(pmd))
> > +		return 0;
> > +
> > +	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
> > +	arch_enter_lazy_mmu_mode();
> > +	for (; addr != end; pte++, addr += PAGE_SIZE) {
> > +		ptent = *pte;
> > +
> > +		if (!pte_present(ptent))
> > +			continue;
> > +
> > +		page = vm_normal_page(vma, addr, ptent);
> > +		if (!page)
> > +			continue;
> > +
> 
> 	-ss
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo-Bw31MaZKKs0EbZ0PF+XxCw@public.gmane.org  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org"> email-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org </a>

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Date: Thu, 5 Nov 2015 08:40:55 +0900
From: Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH v2 01/13] mm: support madvise(MADV_FREE)
Message-ID: <20151104234055.GB7357@bbox>
References: <1446600367-7976-1-git-send-email-minchan@kernel.org>
 <1446600367-7976-2-git-send-email-minchan@kernel.org>
 <20151104022951.GA3744@swordfish>
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To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael Kerrisk <mtk.manpages@gmail.com>, linux-api@vger.kernel.org, Hugh Dickins <hughd@google.com>, Johannes Weiner <hannes@cmpxchg.org>, Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Jason Evans <je@fb.com>, Daniel Micay <danielmicay@gmail.com>, "Kirill A. Shutemov" <kirill@shutemov.name>, Shaohua Li <shli@kernel.org>, Michal Hocko <mhocko@suse.cz>, yalin.wang2010@gmail.com

On Wed, Nov 04, 2015 at 11:29:51AM +0900, Sergey Senozhatsky wrote:
> On (11/04/15 10:25), Minchan Kim wrote:
> [..]
> > +static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
> > +				unsigned long end, struct mm_walk *walk)
> > +
> > +{
> > +	struct mmu_gather *tlb = walk->private;
> > +	struct mm_struct *mm = tlb->mm;
> > +	struct vm_area_struct *vma = walk->vma;
> > +	spinlock_t *ptl;
> > +	pte_t *pte, ptent;
> > +	struct page *page;
> 
> 
> I'll just ask (probably I'm missing something)
> 
> 	+ pmd_trans_huge_lock() ?

No. It would be deadlock.

> 
> > +	split_huge_page_pmd(vma, addr, pmd);
> > +	if (pmd_trans_unstable(pmd))
> > +		return 0;
> > +
> > +	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
> > +	arch_enter_lazy_mmu_mode();
> > +	for (; addr != end; pte++, addr += PAGE_SIZE) {
> > +		ptent = *pte;
> > +
> > +		if (!pte_present(ptent))
> > +			continue;
> > +
> > +		page = vm_normal_page(vma, addr, ptent);
> > +		if (!page)
> > +			continue;
> > +
> 
> 	-ss
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>