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Date: Wed, 12 Nov 2025 16:58:18 +0100
From: Christoph Hellwig <hch@lst.de>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@gentwo.org>,
	David Rientjes <rientjes@google.com>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Harry Yoo <harry.yoo@oracle.com>,
	Eric Biggers <ebiggers@kernel.org>, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/7] mempool: add mempool_{alloc,free}_bulk
Message-ID: <20251112155818.GA9179@lst.de>
References: <20251111135300.752962-1-hch@lst.de> <20251111135300.752962-8-hch@lst.de> <c691c9c1-a513-4db3-95f6-3d24111680b7@suse.cz> <20251112154754.GB7209@lst.de> <4b72bcad-5174-49c7-ad90-63a9c312df0b@suse.cz>
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On Wed, Nov 12, 2025 at 04:56:19PM +0100, Vlastimil Babka wrote:
> > and doesn't leave random holes?  That's what a quick look at the code
> > suggest, unfortunately the documentation for it totally sucks.
> 
> Yeah I think it's fine with alloc_pages_bulk. It would only be a concern is
> the bulk alloc+mempool user used up part of the allocated array, NULLing
> some earlier pointers but leaving later ones alone, and then attempted to
> refill it.

We could have a sanity check for that.  The cache line is hot anyway,
so another few NULL checks aren't going to cost us much.