kernel.git/arch/powerpc/platforms/pseries/hotplug-memory.c, branch linux-5.8.y

pseries/drmem: don't cache node id in drmem_lmb struct

2020-10-29T09:07:52Z

[ Upstream commit e5e179aa3a39c818db8fbc2dce8d2cd24adaf657 ] At memory hot-remove time we can retrieve an LMB's nid from its corresponding memory_block. There is no need to store the nid in multiple locations. Note that lmb_to_memblock() uses find_memory_block() to get the corresponding memory_block. As find_memory_block() runs in sub-linear time this approach is negligibly slower than what we do at present. In exchange for this lookup at hot-remove time we no longer need to call memory_add_physaddr_to_nid() during drmem_init() for each LMB. On powerpc, memory_add_physaddr_to_nid() is a linear search, so this spares us an O(n^2) initialization during boot. On systems with many LMBs that initialization overhead is palpable and disruptive. For example, on a box with 249854 LMBs we're seeing drmem_init() take upwards of 30 seconds to complete: [ 53.721639] drmem: initializing drmem v2 [ 80.604346] watchdog: BUG: soft lockup - CPU#65 stuck for 23s! [swapper/0:1] [ 80.604377] Modules linked in: [ 80.604389] CPU: 65 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc2+ #4 [ 80.604397] NIP: c0000000000a4980 LR: c0000000000a4940 CTR: 0000000000000000 [ 80.604407] REGS: c0002dbff8493830 TRAP: 0901 Not tainted (5.6.0-rc2+) [ 80.604412] MSR: 8000000002009033 CR: 44000248 XER: 0000000d [ 80.604431] CFAR: c0000000000a4a38 IRQMASK: 0 [ 80.604431] GPR00: c0000000000a4940 c0002dbff8493ac0 c000000001904400 c0003cfffffede30 [ 80.604431] GPR04: 0000000000000000 c000000000f4095a 000000000000002f 0000000010000000 [ 80.604431] GPR08: c0000bf7ecdb7fb8 c0000bf7ecc2d3c8 0000000000000008 c00c0002fdfb2001 [ 80.604431] GPR12: 0000000000000000 c00000001e8ec200 [ 80.604477] NIP [c0000000000a4980] hot_add_scn_to_nid+0xa0/0x3e0 [ 80.604486] LR [c0000000000a4940] hot_add_scn_to_nid+0x60/0x3e0 [ 80.604492] Call Trace: [ 80.604498] [c0002dbff8493ac0] [c0000000000a4940] hot_add_scn_to_nid+0x60/0x3e0 (unreliable) [ 80.604509] [c0002dbff8493b20] [c000000000087c10] memory_add_physaddr_to_nid+0x20/0x60 [ 80.604521] [c0002dbff8493b40] [c0000000010d4880] drmem_init+0x25c/0x2f0 [ 80.604530] [c0002dbff8493c10] [c000000000010154] do_one_initcall+0x64/0x2c0 [ 80.604540] [c0002dbff8493ce0] [c0000000010c4aa0] kernel_init_freeable+0x2d8/0x3a0 [ 80.604550] [c0002dbff8493db0] [c000000000010824] kernel_init+0x2c/0x148 [ 80.604560] [c0002dbff8493e20] [c00000000000b648] ret_from_kernel_thread+0x5c/0x74 [ 80.604567] Instruction dump: [ 80.604574] 392918e8 e9490000 e90a000a e92a0000 80ea000c 1d080018 3908ffe8 7d094214 [ 80.604586] 7fa94040 419d00dc e9490010 714a0088 <2faa0008> 409e00ac e9490000 7fbe5040 [ 89.047390] drmem: 249854 LMB(s) With a patched kernel on the same machine we're no longer seeing the soft lockup. drmem_init() now completes in negligible time, even when the LMB count is large. Fixes: b2d3b5ee66f2 ("powerpc/pseries: Track LMB nid instead of using device tree") Signed-off-by: Scott Cheloha Reviewed-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200811015115.63677-1-cheloha@linux.ibm.com Signed-off-by: Sasha Levin

pseries: Fix 64 bit logical memory block panic

2020-08-21T11:15:01Z

commit 89c140bbaeee7a55ed0360a88f294ead2b95201b upstream. Booting with a 4GB LMB size causes us to panic: qemu-system-ppc64: OS terminated: OS panic: Memory block size not suitable: 0x0 Fix pseries_memory_block_size() to handle 64 bit LMBs. Cc: stable@vger.kernel.org Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200715000820.1255764-1-anton@ozlabs.org Signed-off-by: Greg Kroah-Hartman

powerpc/pseries/hotplug-memory: stop checking is_mem_section_removable()

2020-06-05T02:06:23Z

In commit 53cdc1cb29e8 ("drivers/base/memory.c: indicate all memory blocks as removable"), the user space interface to compute whether a memory block can be offlined (exposed via /sys/devices/system/memory/memoryX/removable) has effectively been deprecated. We want to remove the leftovers of the kernel implementation. When offlining a memory block (mm/memory_hotplug.c:__offline_pages()), we'll start by: 1. Testing if it contains any holes, and reject if so 2. Testing if pages belong to different zones, and reject if so 3. Isolating the page range, checking if it contains any unmovable pages Using is_mem_section_removable() before trying to offline is not only racy, it can easily result in false positives/negatives. Let's stop manually checking is_mem_section_removable(), and let device_offline() handle it completely instead. We can remove the racy is_mem_section_removable() implementation next. We now take more locks (e.g., memory hotplug lock when offlining and the zone lock when isolating), but maybe we should optimize that implementation instead if this ever becomes a real problem (after all, memory unplug is already an expensive operation). We started using is_mem_section_removable() in commit 51925fb3c5c9 ("powerpc/pseries: Implement memory hotplug remove in the kernel"), with the initial hotremove support of lmbs. Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Cc: Nathan Fontenot Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michal Hocko Cc: Oscar Salvador Cc: Baoquan He Cc: Wei Yang Link: http://lkml.kernel.org/r/20200407135416.24093-2-david@redhat.com Signed-off-by: Linus Torvalds

Merge tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2020-04-05T18:12:59Z

Pull powerpc updates from Michael Ellerman: "Slightly late as I had to rebase mid-week to insert a bug fix: - A large series from Nick for 64-bit to further rework our exception vectors, and rewrite portions of the syscall entry/exit and interrupt return in C. The result is much easier to follow code that is also faster in general. - Cleanup of our ptrace code to split various parts out that had become badly intertwined with #ifdefs over the years. - Changes to our NUMA setup under the PowerVM hypervisor which should hopefully avoid non-sensical topologies which can lead to warnings from the workqueue code and other problems. - MAINTAINERS updates to remove some of our old orphan entries and update the status of others. - Quite a few other small changes and fixes all over the map. Thanks to: Abdul Haleem, afzal mohammed, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Balamuruhan S, Cédric Le Goater, Chen Zhou, Christophe JAILLET, Christophe Leroy, Christoph Hellwig, Clement Courbet, Daniel Axtens, David Gibson, Douglas Miller, Fabiano Rosas, Fangrui Song, Ganesh Goudar, Gautham R. Shenoy, Greg Kroah-Hartman, Greg Kurz, Gustavo Luiz Duarte, Hari Bathini, Ilie Halip, Jan Kara, Joe Lawrence, Joe Perches, Kajol Jain, Larry Finger, Laurentiu Tudor, Leonardo Bras, Libor Pechacek, Madhavan Srinivasan, Mahesh Salgaonkar, Masahiro Yamada, Masami Hiramatsu, Mauricio Faria de Oliveira, Michael Neuling, Michal Suchanek, Mike Rapoport, Nageswara R Sastry, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Po-Hsu Lin, Pratik Rajesh Sampat, Rasmus Villemoes, Ravi Bangoria, Roman Bolshakov, Sam Bobroff, Sandipan Das, Santosh S, Sedat Dilek, Segher Boessenkool, Shilpasri G Bhat, Sourabh Jain, Srikar Dronamraju, Stephen Rothwell, Tyrel Datwyler, Vaibhav Jain, YueHaibing" * tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits) powerpc: Make setjmp/longjmp signature standard powerpc/cputable: Remove unnecessary copy of cpu_spec->oprofile_type powerpc: Suppress .eh_frame generation powerpc: Drop -fno-dwarf2-cfi-asm powerpc/32: drop unused ISA_DMA_THRESHOLD powerpc/powernv: Add documentation for the opal sensor_groups sysfs interfaces selftests/powerpc: Fix try-run when source tree is not writable powerpc/vmlinux.lds: Explicitly retain .gnu.hash powerpc/ptrace: move ptrace_triggered() into hw_breakpoint.c powerpc/ptrace: create ppc_gethwdinfo() powerpc/ptrace: create ptrace_get_debugreg() powerpc/ptrace: split out ADV_DEBUG_REGS related functions. powerpc/ptrace: move register viewing functions out of ptrace.c powerpc/ptrace: split out TRANSACTIONAL_MEM related functions. powerpc/ptrace: split out SPE related functions. powerpc/ptrace: split out ALTIVEC related functions. powerpc/ptrace: split out VSX related functions. powerpc/ptrace: drop PARAMETER_SAVE_AREA_OFFSET powerpc/ptrace: drop unnecessary #ifdefs CONFIG_PPC64 powerpc/ptrace: remove unused header includes ...

mm/sparse: rename pfn_present() to pfn_in_present_section()

2020-04-02T16:35:30Z

After introducing mem sub section concept, pfn_present() loses its literal meaning, and will not be necessary a truth on partial populated mem section. Since all of the callers use it to judge an absent section, it is better to rename pfn_present() as pfn_in_present_section(). Signed-off-by: Pingfan Liu Signed-off-by: Andrew Morton Reviewed-by: David Hildenbrand Acked-by: Michael Ellerman [powerpc] Cc: Dan Williams Cc: Michal Hocko Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Leonardo Bras Cc: Nathan Fontenot Cc: Nathan Lynch Link: http://lkml.kernel.org/r/1581919110-29575-1-git-send-email-kernelfans@gmail.com Signed-off-by: Linus Torvalds

powerpc/pseries: Avoid NULL pointer dereference when drmem is unavailable

2020-02-19T11:46:11Z

In guests without hotplugagble memory drmem structure is only zero initialized. Trying to manipulate DLPAR parameters results in a crash. $ echo "memory add count 1" > /sys/kernel/dlpar Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries ... NIP: c0000000000ff294 LR: c0000000000ff248 CTR: 0000000000000000 REGS: c0000000fb9d3880 TRAP: 0300 Tainted: G E (5.5.0-rc6-2-default) MSR: 8000000000009033 CR: 28242428 XER: 20000000 CFAR: c0000000009a6c10 DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0 ... NIP dlpar_memory+0x6e4/0xd00 LR dlpar_memory+0x698/0xd00 Call Trace: dlpar_memory+0x698/0xd00 (unreliable) handle_dlpar_errorlog+0xc0/0x190 dlpar_store+0x198/0x4a0 kobj_attr_store+0x30/0x50 sysfs_kf_write+0x64/0x90 kernfs_fop_write+0x1b0/0x290 __vfs_write+0x3c/0x70 vfs_write+0xd0/0x260 ksys_write+0xdc/0x130 system_call+0x5c/0x68 Taking closer look at the code, I can see that for_each_drmem_lmb is a macro expanding into `for (lmb = &drmem_info->lmbs[0]; lmb <= &drmem_info->lmbs[drmem_info->n_lmbs - 1]; lmb++)`. When drmem_info->lmbs is NULL, the loop would iterate through the whole address range if it weren't stopped by the NULL pointer dereference on the next line. This patch aligns for_each_drmem_lmb and for_each_drmem_lmb_in_range macro behavior with the common C semantics, where the end marker does not belong to the scanned range, and alters get_lmb_range() semantics. As a side effect, the wraparound observed in the crash is prevented. Fixes: 6c6ea53725b3 ("powerpc/mm: Separate ibm, dynamic-memory data from DT format") Cc: stable@vger.kernel.org # v4.16+ Signed-off-by: Libor Pechacek Signed-off-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200131132829.10281-1-msuchanek@suse.de

powerpc/pseries: Advance pfn if section is not present in lmb_is_removable()

2020-01-14T01:41:56Z

In lmb_is_removable(), if a section is not present, it should continue to test the rest of the sections in the block. But the current code fails to do so. Fixes: 51925fb3c5c9 ("powerpc/pseries: Implement memory hotplug remove in the kernel") Cc: stable@vger.kernel.org # v4.1+ Signed-off-by: Pingfan Liu Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1578632042-12415-1-git-send-email-kernelfans@gmail.com

powerpc/pseries/hotplug-memory: Change rc variable to bool

2019-11-13T05:58:10Z

Changes the return variable to bool (as the return value) and avoids doing a ternary operation before returning. Signed-off-by: Leonardo Bras Reviewed-by: David Hildenbrand Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190802133914.30413-1-leonardo@linux.ibm.com

powerpc/pseries/hotplug-memory.c: Replace nested ifs by switch-case

2019-08-05T08:53:04Z

I noticed these nested ifs can be easily replaced by switch-cases, which can improve readability. Signed-off-by: Leonardo Bras Reviewed-by: David Hildenbrand Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190801225251.17864-1-leonardo@linux.ibm.com

Merge tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2019-07-13T23:08:36Z

Pull powerpc updates from Michael Ellerman: "Notable changes: - Removal of the NPU DMA code, used by the out-of-tree Nvidia driver, as well as some other functions only used by drivers that haven't (yet?) made it upstream. - A fix for a bug in our handling of hardware watchpoints (eg. perf record -e mem: ...) which could lead to register corruption and kernel crashes. - Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for vmalloc when using the Radix MMU. - A large but incremental rewrite of our exception handling code to use gas macros rather than multiple levels of nested CPP macros. And the usual small fixes, cleanups and improvements. Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz, Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj Jitindar Singh, Thiago Jung Bauermann, YueHaibing" * tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits) powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state. powerpc/eeh: Handle hugepages in ioremap space ocxl: Update for AFU descriptor template version 1.1 powerpc/boot: pass CONFIG options in a simpler and more robust way powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h powerpc/irq: Don't WARN continuously in arch_local_irq_restore() powerpc/module64: Use symbolic instructions names. powerpc/module32: Use symbolic instructions names. powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h powerpc/module64: Fix comment in R_PPC64_ENTRY handling powerpc/boot: Add lzo support for uImage powerpc/boot: Add lzma support for uImage powerpc/boot: don't force gzipped uImage powerpc/8xx: Add microcode patch to move SMC parameter RAM. powerpc/8xx: Use IO accessors in microcode programming. powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c powerpc/8xx: refactor programming of microcode CPM params. powerpc/8xx: refactor printing of microcode patch name. powerpc/8xx: Refactor microcode write powerpc/8xx: refactor writing of CPM microcode arrays ...