On Thu, Aug 15, 2013 at 7:08 PM, Tang Chen <tangchen@xxxxxxxxxxxxxx> wrote: > On 08/16/2013 04:28 AM, Yinghai Lu wrote: > ...... >>> >>> >>> So, we still need reordering, and put a new requirement that all earlier >>> allocations must be small... >>> >>> I think the root of this issue is that ACPI init point is not early >>> enough in the boot sequence. If it were much earlier already, the whole >>> thing would have been very simple. We are now trying to workaround this >>> issue in the mblock code (which itself is a fine idea), but this ACPI >>> issue still remains and similar issues may come up again in future. >>> >>> For instance, ACPI SCPR/DBGP/DBG2 tables allow the OS to initialize >>> serial console/debug ports at early boot time. The earlier it can be >>> initialized, the better this feature will be. These tables are not >>> currently used by Linux due to a licensing issue, but it could be >>> addressed some time soon. As platforms becoming more complex& legacy >>> >>> free, the needs of ACPI tables will increase. >>> >>> I think moving up the ACPI init point earlier is a good direction. >> >> >> Good point. >> >> If we put acpi_initrd_override in BRK, and can more acpi_boot_table_init() >> much early. ... > > Parsing SRAT earlier is what I want to do in the very beginning indeed. And > now, seems that moving the whole acpi table installation and overriding > earlier > will bring us much more benefits. I have tried this without moving up > acpi_initrd_override in my part1 patch-set. But not in the way Yinghai > mentioned > above. ... > > By "put acpi_initrd_override in BRK", do you mean increase the BRK by > default ? Peter, Do you agree on extending BRK 256k to put copied override acpi tables? then we can find and copy them early in arch/x86/kernel/head64.c::x86_64_start_kernel() or arch/x86/kernel/head_32.S. with that we can move acpi_table init as early as possible in setup_arch(). Thanks Yinghai -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>