On 08/11/2015 10:38 AM, Gavin Shan wrote:
On Mon, Aug 10, 2015 at 07:53:02PM +1000, Alexey Kardashevskiy wrote:
On 08/06/2015 02:11 PM, Gavin Shan wrote:
Each PHB maintains an array helping to translate RID (Request
ID) to PE# with the assumption that PE# takes 8 bits, indicating
that we can't have more than 256 PEs. However, pci_dn->pe_number
already had 4-bytes for the PE#.
The patch extends the PE# capacity so that each of them will be
4-bytes long. Then we can use IODA_INVALID_PE to check one entry
in phb->pe_rmap[] is valid or not.
Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++--
arch/powerpc/platforms/powernv/pci.h | 7 +++----
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 57ba8fd..3094c61 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -786,7 +786,7 @@ static int pnv_ioda_deconfigure_pe(struct pnv_phb *phb, struct pnv_ioda_pe *pe)
/* Clear the reverse map */
for (rid = pe->rid; rid < rid_end; rid++)
- phb->ioda.pe_rmap[rid] = 0;
+ phb->ioda.pe_rmap[rid] = IODA_INVALID_PE;
/* Release from all parents PELT-V */
while (parent) {
@@ -3134,7 +3134,7 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
unsigned long size, pemap_off;
const __be64 *prop64;
const __be32 *prop32;
- int len;
+ int len, i;
u64 phb_id;
void *aux;
long rc;
@@ -3201,6 +3201,10 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
if (prop32)
phb->ioda.reserved_pe = be32_to_cpup(prop32);
+ /* Invalidate RID to PE# mapping */
+ for (i = 0; i < ARRAY_SIZE(phb->ioda.pe_rmap); ++i)
+ phb->ioda.pe_rmap[i] = IODA_INVALID_PE;
+
/* Parse 64-bit MMIO range */
pnv_ioda_parse_m64_window(phb);
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 1dc9578..6f8568e 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -175,11 +175,10 @@ struct pnv_phb {
struct list_head pe_list;
struct mutex pe_list_mutex;
- /* Reverse map of PEs, will have to extend if
- * we are to support more than 256 PEs, indexed
- * bus { bus, devfn }
+ /* Reverse map of PEs, indexed by
+ * { bus, devfn }
*/
- unsigned char pe_rmap[0x10000];
+ int pe_rmap[0x10000];
256k seems to be waste when only tiny fraction of it will ever be used. Using
include/linux/hashtable.h makes sense here, and if you use a hashtable, you
won't have to initialize anything with IODA_INVALID_PE.
I'm not sure if I follow your idea completely. With hash table to trace
RID mapping here, won't more memory needed if all PCI buse numbers (0
to 255) are all valid? It means hash table doesn't have advantage in
memory consumption.
You need 3 bytes - one for a bus and two for devfn - which makes it a
perfect 32bit has key and you only store existing devices in a hash so you
do not waste memory.
On the other hand, searching in hash table buckets
have to iterate list of conflicting items (keys), which is slow comparing
to what we have.
How often do you expect this code to execute? Is not it setup-type and
hotplug only? Unless it is thousands times per second, it is not an issue here.
Actually, I like the idea, using array to map RID to PE#,
which was implemented by Ben.
Where?
/* 32-bit TCE tables allocation */
unsigned long dma32_segcount;
Thanks,
Gavin
--
Alexey
--
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