On Tue, Oct 30, 2018 at 10:43:14PM +0200, Igor Stoppa wrote: > On 30/10/2018 21:20, Matthew Wilcox wrote: > > > > So the API might look something like this: > > > > > > > > void *p = rare_alloc(...); /* writable pointer */ > > > > p->a = x; > > > > q = rare_protect(p); /* read-only pointer */ > > With pools and memory allocated from vmap_areas, I was able to say > > protect(pool) > > and that would do a swipe on all the pages currently in use. > In the SELinux policyDB, for example, one doesn't really want to > individually protect each allocation. > > The loading phase happens usually at boot, when the system can be assumed to > be sane (one might even preload a bare-bone set of rules from initramfs and > then replace it later on, with the full blown set). > > There is no need to process each of these tens of thousands allocations and > initialization as write-rare. > > Would it be possible to do the same here? What Andy is proposing effectively puts all rare allocations into one pool. Although I suppose it could be generalised to multiple pools ... one mm_struct per pool. Andy, what do you think to doing that? > > but we'd probably wrap it in list_for_each_rare_entry(), just to be nicer. > > This seems suspiciously close to the duplication of kernel interfaces that I > was roasted for :-) Can you not see the difference between adding one syntactic sugar function and duplicating the entire infrastructure?
