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Date: Thu, 6 Mar 2025 00:33:42 +0100
From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>, Carlos Maiolino <cem@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Dave Chinner <dchinner@redhat.com>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 07/12] xfs: convert buffer cache to use high order
 folios
Message-ID: <20250305233342.GB613@lst.de>
References: <20250305140532.158563-1-hch@lst.de> <20250305140532.158563-8-hch@lst.de> <Z8i5HSS1ppbtQiJc@dread.disaster.area>
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On Thu, Mar 06, 2025 at 07:50:37AM +1100, Dave Chinner wrote:
> This may be one of the reasons why you don't see any change in real
> performance with 64kB directory blocks - we spend more time in
> folio allocation because of compaction overhead than we gain back
> from avoiding the use of vmapped buffers....
> 
> i.e.
> 	if (size > PAGE_SIZE) {
> 		if (!is_power_of_2(size))
> 			goto fallback;
> 		gfp_mask ~= __GFP_DIRECT_RECLAIM;
> 		gfp_mask |= __GFP_NORETRY;
> 	}
> 	folio = folio_alloc(gfp_mask, get_order(size));

I'll give it a try.