[I'm travelling, so expect some major delays in responding to email] Hi Jia,
On Sun, 26 Aug 2018 10:00:51 +0100, Jia He <[email protected]> wrote: > > There is a WARN_ON when my QDF2400 server boots up (pagesize is 4k) [snip] > In its_alloc_lpi_tables, lpi_id_bits is 24, without this patch, > its_allocate_prop_table will try to allocate 16M(order 12 if > pagesize=4k). Thus it causes the WARN_ON. Gah! QDF and its 24bit INTIDs... Making life hell for everyone ;-) Sorry for breaking it. > > This patch fixes it by limiting the lpi_id_bits. > > Signed-off-by: Jia He <[email protected]> > --- > drivers/irqchip/irq-gic-v3-its.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c > b/drivers/irqchip/irq-gic-v3-its.c > index 316a575..79e6993 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -1624,8 +1624,11 @@ static void its_free_prop_table(struct page *prop_page) > static int __init its_alloc_lpi_tables(void) > { > phys_addr_t paddr; > + u32 max_bits; /*max order limitation in alloc_page*/ > > - lpi_id_bits = GICD_TYPER_ID_BITS(gic_rdists->gicd_typer); > + max_bits = PAGE_SHIFT + MAX_ORDER - 1; > + lpi_id_bits = min_t(u32, max_bits, > + GICD_TYPER_ID_BITS(gic_rdists->gicd_typer)); > gic_rdists->prop_page = its_allocate_prop_table(GFP_NOWAIT); > if (!gic_rdists->prop_page) { > pr_err("Failed to allocate PROPBASE\n"); > -- > 1.8.3.1 > I find it rather odd that we end-up with different interrupt ranges depending on the CPU page size. Also, allocating that much memory for LPIs is rather pointless, as we actually have a pretty low limit of interrupts the system can deal with (see IRQ_BITMAP_BITS, which is slightly more than 8k). I've so far seen *one* request to push it up, but I doubt that it is a real use case. Capping lpi_id_bits at 16 (which is what we had before) is plenty, will save a some memory, and gives some margin before we need to push it up again. Thanks, M. -- Jazz is not dead, it just smell funny.
