On Thu, 12 Jul 2018 16:40:12 +0200 Dominique Martinet <asmadeus@xxxxxxxxxxxxx> wrote: > Greg Kurz wrote on Thu, Jul 12, 2018: > > This is true when all tags have been used at least once. But the current code > > lazily allocates the wait_queue_head_t, ie, only when a tag is used for the > > first time. Your patch causes a full row of wait_quest_head_t to be pre-allocated. > > > > ie, P9_ROW_MAXTAG * 24 = 255 * 24 = 6120 > > > > instead of (P9_ROW_MAXTAG * 8) + 24 = 255 * 8 + 24 = 2064 > > > > This is nearly a page of allocated memory that might be never used. > > > > Not sure if this is a problem though... > > I thought the exact same, but the next patch in the serie removes that > array and allocates even more lazily with a slab, so this was a > no-brainer :) > Ah ? I haven't started looking at that *big* other patch yet... :)
