From: Matthew Wilcox <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 18/25] mm: Allow large pages to be added to the page cache
Date: Sat, 6 Jun 2020 20:04:51 -0700 [thread overview]
Message-ID: <20200607030451.GR19604@bombadil.infradead.org> (raw)
In-Reply-To: <20200504031036.GB16070@bombadil.infradead.org>
On Sun, May 03, 2020 at 08:10:36PM -0700, Matthew Wilcox wrote:
> On Wed, Apr 29, 2020 at 06:36:50AM -0700, Matthew Wilcox wrote:
> > @@ -886,7 +906,7 @@ static int __add_to_page_cache_locked(struct page *page,
> > /* Leave page->index set: truncation relies upon it */
> > if (!huge)
> > mem_cgroup_cancel_charge(page, memcg, false);
> > - put_page(page);
> > + page_ref_sub(page, nr);
> > return xas_error(&xas);
> > }
> > ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO);
>
> This is wrong. page_ref_sub() will not call __put_page() if the refcount
> gets to zero. What do people prefer?
*sigh*. It's not wrong. The caller holds a reference on the page
already, so calling page_ref_sub() will never reduce the refcount to 0.
The latest version looks like this:
+ page_ref_sub(page, nr);
+ VM_BUG_ON_PAGE(page_count(page) <= 0, page);
next prev parent reply other threads:[~2020-06-07 3:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 13:36 [PATCH v3 00/25] Large pages in the page cache Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 01/25] mm: Allow hpages to be arbitrary order Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 02/25] mm: Introduce thp_size Matthew Wilcox
2020-05-06 17:59 ` Yang Shi
2020-04-29 13:36 ` [PATCH v3 03/25] mm: Introduce thp_order Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 04/25] mm: Introduce offset_in_thp Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 05/25] fs: Add a filesystem flag for large pages Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 06/25] fs: Introduce i_blocks_per_page Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 07/25] fs: Make page_mkwrite_check_truncate thp-aware Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 08/25] fs: Support THPs in zero_user_segments Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 09/25] bio: Add bio_for_each_thp_segment_all Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 10/25] iomap: Support arbitrarily many blocks per page Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 11/25] iomap: Support large pages in iomap_adjust_read_range Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 12/25] iomap: Support large pages in read paths Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 13/25] iomap: Support large pages in write paths Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 14/25] iomap: Inline data shouldn't see large pages Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 15/25] xfs: Support " Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 16/25] mm: Make prep_transhuge_page return its argument Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 17/25] mm: Add __page_cache_alloc_order Matthew Wilcox
2020-05-06 18:03 ` Yang Shi
2020-06-07 3:08 ` Matthew Wilcox
2020-06-09 17:38 ` Yang Shi
2020-04-29 13:36 ` [PATCH v3 18/25] mm: Allow large pages to be added to the page cache Matthew Wilcox
2020-05-04 3:10 ` Matthew Wilcox
2020-05-06 18:32 ` Yang Shi
2020-06-07 3:04 ` Matthew Wilcox [this message]
2020-04-29 13:36 ` [PATCH v3 19/25] mm: Allow large pages to be removed from " Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 20/25] mm: Remove page fault assumption of compound page size Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 21/25] mm: Add DEFINE_READAHEAD Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 22/25] mm: Make page_cache_readahead_unbounded take a readahead_control Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 23/25] mm: Make __do_page_cache_readahead " Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 24/25] mm: Add large page readahead Matthew Wilcox
2020-04-29 13:36 ` [PATCH v3 25/25] mm: Align THP mappings for non-DAX Matthew Wilcox
2020-04-29 15:40 ` [PATCH v3 00/25] Large pages in the page cache Kirill A. Shutemov
2020-04-29 15:45 ` Kirill A. Shutemov
2020-04-30 11:34 ` Matthew Wilcox
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