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Date:   Sat, 14 Nov 2020 15:22:52 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Christoph Hellwig <hch@lst.de>
Cc:     linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        akpm@linux-foundation.org, hughd@google.com, hannes@cmpxchg.org,
        yang.shi@linux.alibaba.com, dchinner@redhat.com,
        linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
        William Kucharski <william.kucharski@oracle.com>
Subject: Re: [PATCH v4 13/16] mm: Pass pvec directly to find_get_entries
Message-ID: <20201114152252.GM17076@casper.infradead.org>
References: <20201112212641.27837-1-willy@infradead.org>
 <20201112212641.27837-14-willy@infradead.org>
 <20201114102133.GN19102@lst.de>
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On Sat, Nov 14, 2020 at 11:21:33AM +0100, Christoph Hellwig wrote:
> On Thu, Nov 12, 2020 at 09:26:38PM +0000, Matthew Wilcox (Oracle) wrote:
> > +	pvec->nr = ret;
> >  	return ret;
> 
> Do we need to return the number of found entries in addition to storing
> it in the pagevec?

We really only need a bool -- is pvec->nr zero or not.  But we have the
number calculated so we may as well return it.  All the current find_*()
behave this way and I haven't seen enough reason to change it yet.
Making it return void just makes the callers uglier.  I have a batch of
patches to do something similar for find_get_pages / find_get_pages_range
/ pagevec_lookup / pagevec_lookup_range, but I don't need them for the
THP patchset, so I haven't sent them yet.