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From: Jason Gunthorpe <jgg@nvidia.com>
To: David Hildenbrand <david@redhat.com>
Cc: x86@kernel.org, Jan Kara <jack@suse.cz>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Yang Shi <shy828301@gmail.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Xu <peterx@redhat.com>, Michal Hocko <mhocko@kernel.org>,
	linux-mm@kvack.org, Donald Dutile <ddutile@redhat.com>,
	Liang Zhang <zhangliang5@huawei.com>,
	Borislav Petkov <bp@alien8.de>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
	Paul Mackerras <paulus@samba.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	linux-s390@vger.kernel.org, Vasily Gorbik <gor@linux.ibm.com>,
	Rik van Riel <riel@surriel.com>, Hugh Dickins <hughd@google.com>,
	Matthew Wilcox <willy@infradead.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Ingo Molnar <mingo@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	David Rientjes <rientjes@google.com>,
	Pedro Gomes <pedrodemargomes@gmail.com>,
	Jann Horn <jannh@google.com>, John Hubbard <jhubbard@nvidia.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Shakeel Butt <shakeelb@google.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vlastimil Babka <vbabka@suse.cz>,
	Oded Gabbay <oded.gabbay@gmail.com>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Nadav Amit <namit@vmware.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Roman Gushchin <guro@fb.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Mike Kravetz <mike.kravetz@oracle.com>
Subject: Re: [PATCH v1 0/7] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages
Date: Fri, 18 Mar 2022 20:48:50 -0300	[thread overview]
Message-ID: <20220318234850.GD11336@nvidia.com> (raw)
In-Reply-To: <20220315141837.137118-1-david@redhat.com>

On Tue, Mar 15, 2022 at 03:18:30PM +0100, David Hildenbrand wrote:
> This is just the natural follow-up of part 2, that will also further
> reduce "wrong COW" on the swapin path, for example, when we cannot remove
> a page from the swapcache due to concurrent writeback, or if we have two
> threads faulting on the same swapped-out page. Fixing O_DIRECT is just a
> nice side-product :)

I know I would benefit alot from a description of the swap specific
issue a bit more. Most of this message talks about clear_refs which I
do understand a bit better.

Is this talking about what happens after a page gets swapped back in?
eg the exclusive bit is missing when the page is recreated?

Otherwise nothing stood out to me here, but I know almost nothing
about swap.

Thanks,
Jason

  parent reply	other threads:[~2022-03-18 23:50 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-15 14:18 [PATCH v1 0/7] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 1/7] mm/swap: remember PG_anon_exclusive via a swp pte bit David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 2/7] mm/debug_vm_pgtable: add tests for __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 3/7] x86/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 4/7] arm64/pgtable: " David Hildenbrand
2022-03-16 18:27   ` Catalin Marinas
2022-03-17 10:04     ` David Hildenbrand
2022-03-17 17:58       ` Catalin Marinas
2022-03-18  9:59         ` David Hildenbrand
2022-03-18 11:33           ` Catalin Marinas
2022-03-18 14:14             ` David Hildenbrand
2022-03-21 14:38     ` Will Deacon
2022-03-21 14:39       ` Will Deacon
2022-03-21 15:07       ` David Hildenbrand
2022-03-21 17:44         ` Will Deacon
2022-03-21 18:27           ` Catalin Marinas
2022-03-22  9:46             ` David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 5/7] s390/pgtable: " David Hildenbrand
2022-03-15 16:21   ` Gerald Schaefer
2022-03-15 16:37     ` David Hildenbrand
2022-03-15 16:58       ` David Hildenbrand
2022-03-15 17:12         ` David Hildenbrand
2022-03-15 17:14           ` David Hildenbrand
2022-03-16 10:56           ` Gerald Schaefer
2022-03-16 11:06             ` David Hildenbrand
2022-03-16 13:01             ` Christian Borntraeger
2022-03-16 13:27               ` Gerald Schaefer
2022-03-16 14:00                 ` David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 6/7] powerpc/pgtable: remove _PAGE_BIT_SWAP_TYPE for book3s David Hildenbrand
2022-03-15 14:18 ` [PATCH v1 7/7] powerpc/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE " David Hildenbrand
2022-03-18 23:48 ` Jason Gunthorpe [this message]
2022-03-19 11:17   ` [PATCH v1 0/7] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages David Hildenbrand

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