On Mon, Jul 05, 2021 at 08:57:54AM +0530, Anshuman Khandual wrote: > > On 7/1/21 6:27 PM, Matthew Wilcox wrote: > > On Thu, Jul 01, 2021 at 10:51:27AM +0530, Anshuman Khandual wrote: > >> > >> > >> On 5/20/21 4:47 PM, Matthew Wilcox wrote: > >>> On Wed, May 19, 2021 at 01:03:06PM +0530, Anshuman Khandual wrote: > >>>> Split ptlocks need not be defined and allocated unless they are being used. > >>>> ALLOC_SPLIT_PTLOCKS is inherently dependent on USE_SPLIT_PTE_PTLOCKS. This > >>>> just makes it explicit and clear. While here drop the spinlock_t element > >>>> from the struct page when USE_SPLIT_PTE_PTLOCKS is not enabled. > >>> > >>> I didn't spot this email yesterday. I'm not a fan. Isn't struct page > >>> already complicated enough without adding another ifdef to it? Surely > >>> there's a better way than this. > >> > >> This discussion thread just got dropped off the radar, sorry about it. > >> None of the spinlock_t elements are required unless split ptlocks are > >> in use. I understand your concern regarding yet another #ifdef in the > >> struct page definition. But this change is simple and minimal. Do you > >> have any other particular alternative in mind which I could explore ? > > > > Do nothing? I don't understand what problem you're trying to solve. > > Currently there is an element (spinlock_t ptl) in the struct page for page > table lock. Although a struct page based spinlock is not even required in > case USE_SPLIT_PTE_PTLOCKS evaluates to be false. Is not that something to > be fixed here i.e drop the splinlock_t element if not required ? No? It doesn't actually cause any problems, does it?
