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U2FsdGVkX1+Tu/Wr066TYPyNY22mh+z+/e5vaDLaFNWXK9L2qzyEwF7xIIVjN+VhKAL9CeFd09Mx381WDkCQA+jTBLwodgEnrPmeyAbZRCNyDj5o+rE+9FOhANXTXEbBBJ9gfCLluL5LZi21uficc7iCGzz+trJOYjZFWT/ewnYhA0gSmz61ivqSQZcsTc0yykpkqQcN1x4FiPSnwdGCZNzwCxWe1KqrgCwDTC1pF3+cdwwLH5p4GZ/7q9K52kBsOiWwN9a3r/gYMAkZcQ2Pg24ZdMYj2xmGyTMp24e1nBPHZNovKQxuggt1jVMRPO5L7Tab+2DNfrkL1enLJdMddMNMfzn7V6K8F1RgvNKqARHYZUWWntwpYgtMbm4PsD4v+Hm0ZUex0JQldocsB6W3dJIAu4t9SqZNIkxrDW+XtnrU00jLglCeSZ0BoVAjttqdIOXe0vNoCPnZwJRdyHItaC0wyR2+0jN5t0UY1nQ/R2kasECAD8zd96Xj3cKThK6dAfy0mDUzevbI5WZKm0PJPCyARqZLo3MWG+89fh4hdU3ZO2jXoba7kvuj1U0PiZwoppfdHnBukQ8aAFmHLE63CMYwDYwL1i325SRKnpS96MVdJbjB1f5i7rFqFkb/OklSKO6ERP5nqRaeYNyI/ogflsb5OGZEglMkxs3sBRsA6tT0slTRBkCLR5xpXb5+FyRNJ2Bp9V83YjnBVRFqP5sXwgbKovJUlNOY5zFmybZtQp5MAO2NIVexxfk+g6OmjpUkyZswp+9b50sLEWBnZX+4duHramwrLfK4PdwdU7ZKYzWF33/HZ0BwQEq1Q3eLKr202N88TddL3OWKb+voIaDHMT2C89TBCwx2JRLrR8kRLujsECjUHASZBPrbsgd4DMUPG05dAC8D69HDV9xIuKNIMXl1Woedk923U1z+RHM2U13yyBLacfu0U8WUlhUNT+lYYtebwOKOdXRPqfEgauc 4l5X08+l 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15:27, Lorenzo Stoakes wrote: > > On Tue, Jun 10, 2025 at 03:24:16PM +0200, David Hildenbrand wrote: > > > On 10.06.25 14:07, Lorenzo Stoakes wrote: > > > > OK so I think the best solution here is to just update check_ops_valid(), which > > > > was kind of sucky anyway (we check everywhere but walk_page_range_mm() to > > > > enforce the install pte thing). > > > > > > > > Let's do something like: > > > > > > > > #define OPS_MAY_INSTALL_PTE (1<<0) > > > > #define OPS_MAY_AVOID_LOCK (1<<1) > > > > > > > > and update check_ops_valid() to take a flags or maybe 'capabilities' field. > > > > > > > > Then check based on this e.g.: > > > > > > > > if (ops->install_pte && !(capabilities & OPS_MAY_INSTALL_PTE)) > > > > return false; > > > > > > > > if (ops->walk_lock == PGWALK_NOLOCK && !(capabilities & OPS_MAY_AVOID_LOCK)) > > > > return false; > > > > > > > > > > Hm. I mean, we really only want to allow this lockless check for > > > walk_kernel_page_table_range(), right? > > > > > > Having a walk_kernel_page_table_range_lockeless() might (or might not) be > > > better, to really only special-case this specific path. > > > > Agree completely, Dev - let's definitely do this. > > > > > > > > So, I am wondering if we should further start splitting the > > > kernel-page-table walker up from the mm walker, at least on the "entry" > > > function for now. > > > > How do you mean? > > In particular, "struct mm_walk_ops" > > does not quite make sense when not actually walking a "real" mm . > > So maybe we should start having a separate structure where *vma, > install_pte, walk_lock, hugetlb* does not even exist. > > It might be a bit of churn, though ... not sure if there could be an easy > translation layer for now. But you know... I looove churn right? <3 <3 <3 :))) That's a nice idea, but I think something that should be a follow up. Quite honestly I hate a lot about this code. I did some refactoring before, and I might do some again. todo++; ;) I can tie this together actually with Muchun's suggestions from https://lore.kernel.org/all/1AA4A4B3-AEBE-484A-8EE2-35A15035E748@linux.dev/ in my 'page walk improvement' todo sub-list... > > -- > Cheers, > > David / dhildenb >