From: Matthew Wilcox <willy@infradead.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
nvdimm@lists.linux.dev, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, djwong@kernel.org,
dan.j.williams@intel.com, david@fromorbit.com, hch@infradead.org,
jane.chu@oracle.com, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v10 2/9] mm: factor helpers for memory_failure_dev_pagemap
Date: Tue, 1 Feb 2022 21:03:51 +0000 [thread overview]
Message-ID: <YfmgNyG3mfxD/3nS@casper.infradead.org> (raw)
In-Reply-To: <20220127124058.1172422-3-ruansy.fnst@fujitsu.com>
On Thu, Jan 27, 2022 at 08:40:51PM +0800, Shiyang Ruan wrote:
> +static int mf_generic_kill_procs(unsigned long long pfn, int flags,
> + struct dev_pagemap *pgmap)
> +{
> + struct page *page = pfn_to_page(pfn);
> + LIST_HEAD(to_kill);
> + dax_entry_t cookie;
> +
> + /*
> + * Prevent the inode from being freed while we are interrogating
> + * the address_space, typically this would be handled by
> + * lock_page(), but dax pages do not use the page lock. This
> + * also prevents changes to the mapping of this pfn until
> + * poison signaling is complete.
> + */
> + cookie = dax_lock_page(page);
> + if (!cookie)
> + return -EBUSY;
> +
> + if (hwpoison_filter(page))
> + return 0;
> +
> + if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
> + /*
> + * TODO: Handle HMM pages which may need coordination
> + * with device-side memory.
> + */
> + return -EBUSY;
> + }
> +
> + /*
> + * Use this flag as an indication that the dax page has been
> + * remapped UC to prevent speculative consumption of poison.
> + */
> + SetPageHWPoison(page);
> +
> + /*
> + * Unlike System-RAM there is no possibility to swap in a
> + * different physical page at a given virtual address, so all
> + * userspace consumption of ZONE_DEVICE memory necessitates
> + * SIGBUS (i.e. MF_MUST_KILL)
> + */
> + flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
> + collect_procs(page, &to_kill, true);
> +
> + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
> + dax_unlock_page(page, cookie);
> + return 0;
> +}
There's an assumption here that fsdax only has order-0 pages.
pfn_to_page() is going to return the precise page for that pfn, but then
page->mapping and page->index are not valid for tail pages.
I'm currently trying to folio-ise memory-failure.c, and it is not
going well! There are several places where it's hard to tell
what should happen.
next prev parent reply other threads:[~2022-02-01 21:04 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-27 12:40 [PATCH v10 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
2022-01-27 12:40 ` [PATCH v10 1/9] dax: Introduce holder for dax_device Shiyang Ruan
2022-01-27 16:13 ` kernel test robot
2022-01-27 16:44 ` kernel test robot
2022-02-02 13:03 ` Christoph Hellwig
2022-02-13 12:58 ` [PATCH v10.1 " Shiyang Ruan
2022-02-15 22:06 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 2/9] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2022-02-01 21:03 ` Matthew Wilcox [this message]
2022-02-15 22:11 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 3/9] pagemap,pmem: Introduce ->memory_failure() Shiyang Ruan
2022-02-15 22:38 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 4/9] fsdax: fix function description Shiyang Ruan
2022-02-02 13:04 ` Christoph Hellwig
2022-02-15 23:51 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 5/9] fsdax: Introduce dax_load_page() Shiyang Ruan
2022-02-16 1:34 ` Dan Williams
2022-02-16 3:02 ` Shiyang Ruan
2022-02-16 3:07 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 6/9] mm: move pgoff_address() to vma_pgoff_address() Shiyang Ruan
2022-02-16 1:37 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 7/9] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2022-02-16 1:47 ` Dan Williams
2022-02-16 1:49 ` Dan Williams
2022-01-27 12:40 ` [PATCH v10 8/9] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2022-01-27 17:56 ` kernel test robot
2022-01-27 19:39 ` kernel test robot
2022-02-01 20:41 ` Darrick J. Wong
2022-02-13 13:02 ` [PATCH v10.1 " Shiyang Ruan
2022-02-15 1:46 ` Darrick J. Wong
2022-02-15 9:42 ` Shiyang Ruan
2022-02-16 1:56 ` [PATCH v10 " Dan Williams
2022-01-27 12:40 ` [PATCH v10 9/9] fsdax: set a CoW flag when associate reflink mappings Shiyang Ruan
2022-02-16 2:09 ` Dan Williams
2022-02-16 2:55 ` Shiyang Ruan
2022-02-16 3:09 ` Dan Williams
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