On Wed, May 22, 2024 at 04:52:45PM +0100, Steven Price wrote: > On 15/05/2024 12:01, Catalin Marinas wrote: > > On Fri, Apr 12, 2024 at 09:42:11AM +0100, Steven Price wrote: > >> @@ -3432,7 +3468,16 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id, > >> nr_ites = max(2, nvecs); > >> sz = nr_ites * (FIELD_GET(GITS_TYPER_ITT_ENTRY_SIZE, its->typer) + 1); > >> sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1; > >> - itt = kzalloc_node(sz, GFP_KERNEL, its->numa_node); > >> + itt_order = get_order(sz); > >> + page = its_alloc_shared_pages_node(its->numa_node, > >> + GFP_KERNEL | __GFP_ZERO, > >> + itt_order); > > > > How much do we waste by going for a full page always if this is going to > > be used on the host? > > sz is a minimum of ITS_ITT_ALIGN*2-1 - which is 511 bytes. So > potentially PAGE_SIZE-512 bytes could be wasted here (minus kmalloc > overhead). That I figured out as well but how many times is this path called with a size smaller than a page? -- Catalin
