linux-kernel - Re: [PATCH v4 4/9] binder: remove struct binder_lru

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Message-ID: <Zz1NQXgk96vqHHFr@casper.infradead.org>
Date: Wed, 20 Nov 2024 02:45:21 +0000
From: Matthew Wilcox <willy@...radead.org>
To: Carlos Llamas <cmllamas@...gle.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Arve Hjønnevåg <arve@...roid.com>,
	Todd Kjos <tkjos@...roid.com>, Martijn Coenen <maco@...roid.com>,
	Joel Fernandes <joel@...lfernandes.org>,
	Christian Brauner <brauner@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	linux-kernel@...r.kernel.org, kernel-team@...roid.com,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: Re: [PATCH v4 4/9] binder: remove struct binder_lru_page

On Tue, Nov 19, 2024 at 08:16:07PM +0000, Carlos Llamas wrote:
> If you are planning to keep page->private, I think we can just hang our
> binder items in there. Something like...
> 
> 	struct binder_page_items *bp;
> 	struct page *p;
> 
> 	bp = kzalloc(sizeof(*bp), GFP_KERNEL);
> 	bp->alloc = alloc;
> 	INIT_LIST_HEAD(&bp->lru);
> 	bp->index = index;
> 
> 	p = alloc_page(...);
> 	p->private = (unsigned long)bp;
> 
> This would be absolutely fine in binder. Is this what you had in mind
> for current users of page->lru?

Something like that, yes.  Although you wouldn't even need to use
page->private for it; you'd be able to use page->memdesc directly,
and then not be in the way of shrinking to 8 bytes.