| Message ID | 20210609004419.936873-1-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: MMU enabled kexec relocation | expand |
On Tue, Jun 8, 2021 at 8:44 PM Pavel Tatashin <pasha.tatashin@soleen.com> wrote: > > Changelog: > v15: > - Changed trans_pgd_copy_el2_vectors() to use vector table that > only shared by kexec and hibernate. This way sync does not have > dangling branch that was recently introduced. (Reported by Marc > Zyngier) > - Renamed is_hyp_callable() to is_hyp_nvhe() as requested by Marc > Zyngier > - Clean-ups, comment fixes. > - Sync with upstream 368094df48e680fa51cedb68537408cfa64b788e > v14: > - Fixed a bug in "arm64: hyp-stub: Move elx_sync into the vectors" > that was noticed by Marc Zyngier > - Merged with upstream > v13: > - Fixed a hang on ThunderX2, thank you Pingfan Liu for reporting > the problem. In relocation function we need civac not ivac, we > need to clean data in addition to invalidating it. > Since I was using ThunderX2 machine I also measured the new > performance data on this large ARM64 server. The MMU improves > kexec relocation 190 times on this machine! (see below for > raw data). Saves 7.5s during CentOS kexec reboot. > v12: > - A major change compared to previous version. Instead of using > contiguous VA range a copy of linear map is now used to perform > copying of segments during relocation as it was agreed in the > discussion of version 11 of this project. > - In addition to using linear map, I also took several ideas from > James Morse to better organize the kexec relocation: > 1. skip relocation function entirely if that is not needed > 2. remove the PoC flushing function since it is not needed > anymore with MMU enabled. > v11: > - Fixed missing KEXEC_CORE dependency for trans_pgd.c > - Removed useless "if(rc) return rc" statement (thank you Tyler Hicks) > - Another 12 patches were accepted into maintainer's get. > Re-based patches against: > https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git > Branch: for-next/kexec > v10: > - Addressed a lot of comments form James Morse and from Marc Zyngier > - Added review-by's > - Synchronized with mainline > > v9: - 9 patches from previous series landed in upstream, so now series > is smaller > - Added two patches from James Morse to address idmap issues for machines > with high physical addresses. > - Addressed comments from Selin Dag about compiling issues. He also tested > my series and got similar performance results: ~60 ms instead of ~580 ms > with an initramfs size of ~120MB. > v8: > - Synced with mainline to keep series up-to-date > v7: > -- Addressed comments from James Morse > - arm64: hibernate: pass the allocated pgdp to ttbr0 > Removed "Fixes" tag, and added Added Reviewed-by: James Morse > - arm64: hibernate: check pgd table allocation > Sent out as a standalone patch so it can be sent to stable > Series applies on mainline + this patch > - arm64: hibernate: add trans_pgd public functions > Remove second allocation of tmp_pg_dir in swsusp_arch_resume > Added Reviewed-by: James Morse <james.morse@arm.com> > - arm64: kexec: move relocation function setup and clean up > Fixed typo in commit log > Changed kern_reloc to phys_addr_t types. > Added explanation why kern_reloc is needed. > Split into four patches: > arm64: kexec: make dtb_mem always enabled > arm64: kexec: remove unnecessary debug prints > arm64: kexec: call kexec_image_info only once > arm64: kexec: move relocation function setup > - arm64: kexec: add expandable argument to relocation function > Changed types of new arguments from unsigned long to phys_addr_t. > Changed offset prefix to KEXEC_* > Split into four patches: > arm64: kexec: cpu_soft_restart change argument types > arm64: kexec: arm64_relocate_new_kernel clean-ups > arm64: kexec: arm64_relocate_new_kernel don't use x0 as temp > arm64: kexec: add expandable argument to relocation function > - arm64: kexec: configure trans_pgd page table for kexec > Added invalid entries into EL2 vector table > Removed KEXEC_EL2_VECTOR_TABLE_SIZE and KEXEC_EL2_VECTOR_TABLE_OFFSET > Copy relocation functions and table into separate pages > Changed types in kern_reloc_arg. > Split into three patches: > arm64: kexec: offset for relocation function > arm64: kexec: kexec EL2 vectors > arm64: kexec: configure trans_pgd page table for kexec > - arm64: kexec: enable MMU during kexec relocation > Split into two patches: > arm64: kexec: enable MMU during kexec relocation > arm64: kexec: remove head from relocation argument > v6: > - Sync with mainline tip > - Added Acked's from Dave Young > v5: > - Addressed comments from Matthias Brugger: added review-by's, improved > comments, and made cleanups to swsusp_arch_resume() in addition to > create_safe_exec_page(). > - Synced with mainline tip. > v4: > - Addressed comments from James Morse. > - Split "check pgd table allocation" into two patches, and moved to > the beginning of series for simpler backport of the fixes. > Added "Fixes:" tags to commit logs. > - Changed "arm64, hibernate:" to "arm64: hibernate:" > - Added Reviewed-by's > - Moved "add PUD_SECT_RDONLY" earlier in series to be with other > clean-ups > - Added "Derived from:" to arch/arm64/mm/trans_pgd.c > - Removed "flags" from trans_info > - Changed .trans_alloc_page assumption to return zeroed page. > - Simplify changes to trans_pgd_map_page(), by keeping the old > code. > - Simplify changes to trans_pgd_create_copy, by keeping the old > code. > - Removed: "add trans_pgd_create_empty" > - replace init_mm with NULL, and keep using non "__" version of > populate functions. > v3: > - Split changes to create_safe_exec_page() into several patches for > easier review as request by Mark Rutland. This is why this series > has 3 more patches. > - Renamed trans_table to tans_pgd as agreed with Mark. The header > comment in trans_pgd.c explains that trans stands for > transitional page tables. Meaning they are used in transition > between two kernels. > v2: > - Fixed hibernate bug reported by James Morse > - Addressed comments from James Morse: > * More incremental changes to trans_table > * Removed TRANS_FORCEMAP > * Added kexec reboot data for image with 380M in size. > > Enable MMU during kexec relocation in order to improve reboot performance. > > If kexec functionality is used for a fast system update, with a minimal > downtime, the relocation of kernel + initramfs takes a significant portion > of reboot. > > The reason for slow relocation is because it is done without MMU, and thus > not benefiting from D-Cache. > > Performance data > ---------------- > > Cavium ThunderX2: > Kernel Image size: 38M Iniramfs size: 46M Total relocation size: 84M > MMU-disabled: > relocation 7.489539915s > MMU-enabled: > relocation 0.03946095s > > Relocation performance is improved 190 times. > > Broadcom Stingray: > For this experiment, the size of kernel plus initramfs is small, only 25M. > If initramfs was larger, than the improvements would be greater, as time > spent in relocation is proportional to the size of relocation. > > MMU-disabled:: > kernel shutdown 0.022131328s > relocation 0.440510736s > kernel startup 0.294706768s > > Relocation was taking: 58.2% of reboot time > > MMU-enabled: > kernel shutdown 0.032066576s > relocation 0.022158152s > kernel startup 0.296055880s > > Now: Relocation takes 6.3% of reboot time > > Total reboot is x2.16 times faster. > > With bigger userland (fitImage 380M), the reboot time is improved by 3.57s, > and is reduced from 3.9s down to 0.33s HI All, I am looking for reviewers. It provides a great performance boost, but lacks reviewers for the last iterations of the series. Than you, Pasha