Re: [PATCH 02/16] mm: introduce leaf entry type and use to simplify leaf entry logic

From: David Hildenbrand (Red Hat)

Date: Wed Nov 05 2025 - 15:11:52 EST


On 05.11.25 21:05, Lorenzo Stoakes wrote:
On Wed, Nov 05, 2025 at 03:01:00PM -0500, Gregory Price wrote:
On Wed, Nov 05, 2025 at 07:52:36PM +0000, Lorenzo Stoakes wrote:
On Wed, Nov 05, 2025 at 02:25:34PM -0500, Gregory Price wrote:
On Wed, Nov 05, 2025 at 07:06:11PM +0000, Matthew Wilcox wrote:
I thought about doing this but it doesn't really work as the type is
_abstracted_ from the architecture-specific value, _and_ we use what is
currently the swp_type field to identify what this is.

So we would lose the architecture-specific information that any 'hardware leaf'
entry would require and not be able to reliably identify it without losing bits.

Trying to preserve the value _and_ correctly identify it as a present entry
would be difficult.

And I _really_ didn't want to go on a deep dive through all the architectures to
see if we could encode it differently to allow for this.

Rather I think it's better to differentiate between s/w + h/w leaf entries.


Reasonable - names are hard, but just about anything will be better than swp_entry.

SWE / sw_entry seems perfectly reasonable.

I'm not a lover of 'sw' in there it's just... eye-stabby. Is that a word?

I am quite fond of my suggested soft_leaf_t, softleaf_xxx()

We do have soft_dirty.

It will get interesting with pte_swp_soft_dirty() :)

ptw_softlead_soft_dirty() Well, at least I would understand it.