From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 00/25] Large pages in the page cache
Date: Wed, 29 Apr 2020 18:45:42 +0300 [thread overview]
Message-ID: <20200429154542.kcqrtu3zrui5r6ah@box> (raw)
In-Reply-To: <20200429154002.n3mq2ysz37puf73y@box>
On Wed, Apr 29, 2020 at 06:40:02PM +0300, Kirill A. Shutemov wrote:
> On Wed, Apr 29, 2020 at 06:36:32AM -0700, Matthew Wilcox wrote:
> > From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> >
> > This patch set does not pass xfstests. Test at your own risk. It is
> > based on the readahead rewrite which is in Andrew's tree. The large
> > pages somehow manage to fall off the LRU, so the test VM quickly runs
> > out of memory and freezes. To reproduce:
> >
> > # mkfs.xfs /dev/sdb && mount /dev/sdb /mnt && dd if=/dev/zero bs=1M count=2048 of=/mnt/bigfile && sync && sleep 2 && sync && echo 1 >/proc/sys/vm/drop_caches
> > # /host/home/willy/kernel/xarray-2/tools/vm/page-types | grep thp
> > 0x0000000000401800 511 1 ___________Ma_________t____________________ mmap,anonymous,thp
> > 0x0000000000405868 1 0 ___U_lA____Ma_b_______t____________________ uptodate,lru,active,mmap,anonymous,swapbacked,thp
> > # dd if=/mnt/bigfile of=/dev/null bs=2M count=5
> > # /host/home/willy/kernel/xarray-2/tools/vm/page-types | grep thp
> > 0x0000000000400000 2516 9 ______________________t____________________ thp
> > 0x0000000000400028 1 0 ___U_l________________t____________________ uptodate,lru,thp
> > 0x000000000040006c 106 0 __RU_lA_______________t____________________ referenced,uptodate,lru,active,thp
>
> Note that you have 107 pages on LRU. It is only head pages. With order-5
> pages it is over 13MiB.
>
> Looks like everything is fine.
/proc/kpageflags reads page's flag bit directly instead of relying on
PageLRU:
u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
Tail pages don't have this bit set. They rely on head page's flag for
PageLRU().
It would be nice to get it fixed, but I guess it is too late. Somebody may
rely on the current behaviour by now.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-04-29 15:45 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
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 [this message]
2020-04-30 11:34 ` Matthew Wilcox
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