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From: Jan Kara <jack@suse.cz>
To: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>,
	linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	William Kucharski <william.kucharski@oracle.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Yang Shi <yang.shi@linux.alibaba.com>,
	Dave Chinner <dchinner@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 12/12] mm/filemap: Return only head pages from find_get_entries
Date: Wed, 30 Sep 2020 19:08:07 +0200	[thread overview]
Message-ID: <20200930170807.GA15977@quack2.suse.cz> (raw)
In-Reply-To: <20200930123637.GP20115@casper.infradead.org>

On Wed 30-09-20 13:36:37, Matthew Wilcox wrote:
> On Wed, Sep 30, 2020 at 02:15:12PM +0200, Jan Kara wrote:
> > On Mon 14-09-20 14:00:42, Matthew Wilcox (Oracle) wrote:
> > > All callers now expect head (and base) pages, and can handle multiple
> > > head pages in a single batch, so make find_get_entries() behave that way.
> > > Also take the opportunity to make it use the pagevec infrastructure
> > > instead of open-coding how pvecs behave.  This has the side-effect of
> > > being able to append to a pagevec with existing contents, although we
> > > don't make use of that functionality anywhere yet.
> > > 
> > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > 
> > Looks good to me. You can add:
> > 
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > 
> > I'm just curious: What has happened to pagevec_lookup_entries() call in
> > invalidate_inode_pages2_range()? Your series appears to be based on a tree
> > where the call already does not exist...
> 
> That went away in patch 10 of this series.

Ah, I see. Thanks. Then I'm somewhat wondering is really
invalidate_inode_pages2_range() safe for THP head pages? At least the:

	unmap_mapping_pages(mapping, index, 1, false);

doesn't look adequate for THP head pages... do_launder_page() is also
doubtful but probably currently OK because THPs cannot be dirty at this
moment. But how about THPs that are partialy inside start-end range? So far
the function didn't care because it was operating on page basis so it
didn't care but now it is probably relevant... At least it would warrant a
comment in some changelog if you are convinced everything is safe.

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR


  reply	other threads:[~2020-09-30 17:08 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 13:00 [PATCH v2 00/12] Overhaul multi-page lookups for THP Matthew Wilcox (Oracle)
2020-09-14 13:00 ` [PATCH v2 01/12] mm: Make pagecache tagged lookups return only head pages Matthew Wilcox (Oracle)
2020-09-29  9:13   ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 02/12] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping Matthew Wilcox (Oracle)
2020-09-29  8:28   ` Jan Kara
2020-09-29 18:36     ` Matthew Wilcox
2020-09-14 13:00 ` [PATCH v2 03/12] mm/filemap: Add helper for finding pages Matthew Wilcox (Oracle)
2020-09-29  8:27   ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 04/12] mm/filemap: Add mapping_seek_hole_data Matthew Wilcox (Oracle)
2020-09-29  8:46   ` Jan Kara
2020-09-29 12:42     ` Matthew Wilcox
2020-09-29 13:39       ` Matthew Wilcox
2020-09-14 13:00 ` [PATCH v2 05/12] mm: Add and use find_lock_entries Matthew Wilcox (Oracle)
2020-09-29  8:58   ` Jan Kara
2020-09-29 12:48     ` Matthew Wilcox
2020-09-30 10:40       ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 06/12] mm: Add an 'end' parameter to find_get_entries Matthew Wilcox (Oracle)
2020-09-14 13:00 ` [PATCH v2 07/12] mm: Add an 'end' parameter to pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-09-29  9:02   ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 08/12] mm: Remove nr_entries parameter from pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-09-29  9:03   ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 09/12] mm: Pass pvec directly to find_get_entries Matthew Wilcox (Oracle)
2020-09-29  9:07   ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 10/12] mm: Remove pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-09-29  9:08   ` Jan Kara
2020-09-14 13:00 ` [PATCH v2 11/12] mm/truncate,shmem: Handle truncates that split THPs Matthew Wilcox (Oracle)
2020-09-30 11:59   ` Jan Kara
2020-09-30 14:51     ` Matthew Wilcox
2020-09-14 13:00 ` [PATCH v2 12/12] mm/filemap: Return only head pages from find_get_entries Matthew Wilcox (Oracle)
2020-09-30 12:15   ` Jan Kara
2020-09-30 12:36     ` Matthew Wilcox
2020-09-30 17:08       ` Jan Kara [this message]
2020-09-30 17:23         ` Matthew Wilcox
2020-10-01  7:17           ` Jan Kara
2020-10-25 23:19             ` Matthew Wilcox
2020-10-26  9:11               ` Jan Kara
2020-09-28 20:13 ` [PATCH v2 00/12] Overhaul multi-page lookups for THP Matthew Wilcox
2020-09-29  8:50 ` William Kucharski

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