On 2016/01/28 at 17:02, Dmitry Safonov wrote: > On 01/28/2016 05:58 AM, Xunlei Pang wrote: >> Hi Dmitry, >> >> On 2016/01/28 at 03:15, Andrew Morton wrote: >>> On Wed, 27 Jan 2016 14:48:31 +0300 Dmitry Safonov <dsafonov at virtuozzo.com> wrote: >>> >>>> For allocation of kimage failure or kexec_prepare or load segments >>>> errors there is no need to keep crashkernel memory mapped. >>>> It will affect only s390 as map/unmap hook defined only for it. >>>> As on unmap s390 also changes os_info structure let's check return code >>>> and add info only on success. >>>> >>> This conflicts (both mechanically and somewhat conceptually) with >>> Xunlei Pang's "kexec: Introduce a protection mechanism for the >>> crashkernel reserved memory" and "kexec: provide >>> arch_kexec_protect(unprotect)_crashkres()". >>> >>> http://ozlabs.org/~akpm/mmots/broken-out/kexec-introduce-a-protection-mechanism-for-the-crashkernel-reserved-memory.patch >>> http://ozlabs.org/~akpm/mmots/broken-out/kexec-introduce-a-protection-mechanism-for-the-crashkernel-reserved-memory-v4.patch >>> >>> and >>> >>> http://ozlabs.org/~akpm/mmots/broken-out/kexec-provide-arch_kexec_protectunprotect_crashkres.patch >>> http://ozlabs.org/~akpm/mmots/broken-out/kexec-provide-arch_kexec_protectunprotect_crashkres-v4.patch >>> >>> so can we please sort all that out? >> >> Ah, I've checked git-log history, they are almost the same idea, can crash_unmap/map_reserved_pages() >> be re-implemented using the new arch_kexec_unprotect/protect_crashkres() on S390? > Sorry, didn't fetched akpm before sending. > Yes, sounds like really right thing to do to have one united arch-helper. Yeah, as Michael said, "memblock_remove(crash_base, crash_size)" creates a big hole in the kernel pgtable. In order to have one united arch-helper, I guess we can forbid this to let the pgtable setup for crash memory, then we can easily move the logic of crash_map_reserved_pages() to arch_kexec_unprotect_crashkres(), and move crash_unmap_reserved_pages() to arch_kexec_protect_crashkres(). After that crash_map_reserved_pages() called in crash_shrink_memory() can be safely removed as well. Regards, Xunlei >> >> Regards, >> Xunlei >> >>> _______________________________________________ >>> kexec mailing list >>> kexec at lists.infradead.org >>> http://lists.infradead.org/mailman/listinfo/kexec >> > > > -- > Regards, > Dmitry Safonov
