From: Alexander Gordeev <agordeev@linux.ibm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org,
linux-s390@vger.kernel.org, sparclinux@vger.kernel.org,
linux-um@lists.infradead.org
Subject: Re: [PATCH 1/7] mm: Set the pte dirty if the folio is already dirty
Date: Wed, 19 Feb 2025 08:27:21 +0100 [thread overview]
Message-ID: <Z7WH2VPdFvX6reij@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com> (raw)
In-Reply-To: <Z7S-HgdXls65goJx@casper.infradead.org>
On Tue, Feb 18, 2025 at 05:06:38PM +0000, Matthew Wilcox wrote:
...
> > With the above the implicit dirtifying of hugetlb PTEs (as result of
> > mk_huge_pte() -> mk_pte()) in make_huge_pte() is removed:
> >
> > static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
> > bool try_mkwrite)
> > {
> > ...
> > if (try_mkwrite && (vma->vm_flags & VM_WRITE)) {
> > entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
> > vma->vm_page_prot)));
> > } else {
> > entry = huge_pte_wrprotect(mk_huge_pte(page,
> > vma->vm_page_prot));
> > }
>
> Took me a moment to spot how this was getting invoked; for anyone else
> playing along, it's mk_huge_pte() which calls mk_pte().
>
> But I'm not sure how you lose out on the PTE being marked dirty. In
> the first arm that you've quoted, the pte is made dirty anyway. In the
> second arm, it's being writeprotected, so marking it dirty isn't a
> helpful thing to do because writing to it will cause a fault anyway?
>
> I know s390 is a little different, so there's probably something I'm
> missing.
No, it is just me missing the obvious.
next prev parent reply other threads:[~2025-02-19 7:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-17 19:08 [PATCH 0/7] Add folio_mk_pte() and simplify mk_pte() Matthew Wilcox (Oracle)
2025-02-17 19:08 ` [PATCH 1/7] mm: Set the pte dirty if the folio is already dirty Matthew Wilcox (Oracle)
2025-02-18 10:31 ` David Hildenbrand
2025-02-18 16:20 ` Alexander Gordeev
2025-02-18 17:06 ` Matthew Wilcox
2025-02-19 7:27 ` Alexander Gordeev [this message]
2025-02-19 7:33 ` Alexander Gordeev
2025-02-19 8:46 ` Alexander Gordeev
2025-02-17 19:08 ` [PATCH 2/7] mm: Introduce a common definition of mk_pte() Matthew Wilcox (Oracle)
2025-02-18 8:15 ` Geert Uytterhoeven
2025-02-18 10:32 ` David Hildenbrand
2025-02-19 9:07 ` Alexander Gordeev
2025-02-17 19:08 ` [PATCH 3/7] sparc32: Remove custom " Matthew Wilcox (Oracle)
2025-02-17 19:08 ` [PATCH 4/7] x86: " Matthew Wilcox (Oracle)
2025-02-19 20:53 ` Dave Hansen
2025-02-17 19:08 ` [PATCH 5/7] um: " Matthew Wilcox (Oracle)
2025-02-17 19:08 ` [PATCH 6/7] mm: Make mk_pte() definition unconditional Matthew Wilcox (Oracle)
2025-02-18 10:32 ` David Hildenbrand
2025-02-17 19:08 ` [PATCH 7/7] mm: Add folio_mk_pte() Matthew Wilcox (Oracle)
2025-02-18 10:33 ` David Hildenbrand
2025-02-18 10:29 ` [PATCH 0/7] Add folio_mk_pte() and simplify mk_pte() David Hildenbrand
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