Messages in this thread | | | Date | Mon, 30 Jun 2008 02:15:41 -0700 | From | "Yinghai Lu" <> | Subject | Re: [PATCH 1/2] x86 boot: add E820_RESVD_KERN |
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On Mon, Jun 30, 2008 at 12:51 AM, Huang, Ying <ying.huang@intel.com> wrote: > On Mon, 2008-06-30 at 00:34 -0700, Yinghai Lu wrote: >> On Mon, Jun 30, 2008 at 12:03 AM, Huang, Ying <ying.huang@intel.com> wrote: >> > On Fri, 2008-06-27 at 15:05 -0700, Yinghai Lu wrote: >> >> On Thu, Jun 26, 2008 at 7:48 PM, Huang, Ying <ying.huang@intel.com> wrote: >> >> > On Thu, 2008-06-26 at 19:22 -0700, Yinghai Lu wrote: >> >> >> On Thu, Jun 26, 2008 at 2:47 AM, Yinghai Lu <yhlu.kernel@gmail.com> wrote: >> >> >> > On Thu, Jun 26, 2008 at 12:48 AM, Huang, Ying <ying.huang@intel.com> wrote: >> >> >> >> On Thu, 2008-06-26 at 00:25 -0700, Yinghai Lu wrote: >> >> >> >> [...] >> >> >> >>> > if (pfn >= limit_pfn) >> >> >> >>> > @@ -977,7 +978,7 @@ u64 __init early_reserve_e820(u64 startt >> >> >> >>> > return 0; >> >> >> >>> > >> >> >> >>> > addr = round_down(start + size - sizet, align); >> >> >> >>> > - e820_update_range(addr, sizet, E820_RAM, E820_RESERVED); >> >> >> >>> > + e820_update_range(addr, sizet, E820_RAM, E820_RESVD_KERN); >> >> >> >>> >> >> >> >>> this line is not needed. >> >> >> >> >> >> >> >> Why? Memory reserved by early_rserved_e820 should not be saved during >> >> >> >> hibernation? shoudl not be saved by kdump? >> >> >> >> >> >> > >> >> > Can you tell me why this line is not needed? >> >> > >> >> > [...] >> >> >> some like the attach patch... >> >> >> >> >> >> you still can merge parse_setup_data parse_e820_ext >> >> >> also entries in parse_e820_ext is not initialized..., __copy_e820_map >> >> >> will do nothing. >> >> > >> >> > OK. Because some E820 entries are available after parse_setup_data(), >> >> > it is better to call reserve_setup_data() after calling >> >> > parse_setup_data() if update_e820_range() is used instead of >> >> > reserve_early(). >> >> >> >> please modify it and test on your platforms then submit to Ingo.. >> > >> > It seems that there is an issue: >> > >> > - If parse_setup_data() is called before reserve_setup_data(), and there >> > is a conflict between memory area used by setup_data and other memory >> > area, it is possible that the contents of setup_data is changed. So that >> > system may panic before reporting memory area conflict. And it seems >> > that memory area conflict is not checked by e820_update_range(). >> >> what is "other memory area"? returned from find_e820_area? no one use that yet. > > I mean memory area reserved with reserved_early() or e820_update_range() > before reserve_setup_data() is called.
before parse_setup_data, reserve_early is called for 1. kernel text/data/bss + initial pgt 2. ramdisk 3. ebda e820_update_range is not called. at this time early_res have RAM reserved by kernel.
then setup_memory_map is called, so e820 have some ranges...directly from e820 table
next need to call parse_setup_data it will add some entries in e820
then reserve_setup_data is called, it will use e820_update_range to reserve setup_data itself directly in e820
...
> > And because there is no conflict check in e820_update_range(), what to > deal with potential conflict between setup_data and other memory area > regardless which one is reserved earlier?
find_e820_area will make sure it only find ram from e820 and it is not conflict with early_res
> > > Another issue related: > > Because some memmap entries are available via extended E820 memmap > (SETUP_E820_EXT), it is not strictly safe to use e820_update_range() > between setup_memory_map() and parse_setup_data(). It may be better to > parse extended E820 memmap right after setup_memory_map().
will look at the code again..
YH
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