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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E8DBD80015 X-Stat-Signature: 1xmo8k4n7c4ignwmf1e7dryrifmt1m4t X-HE-Tag: 1759910743-215055 X-HE-Meta: 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 NO/1NJia +f5ue3xBbMqHxnhFqAfubxfl+LwJ1vzAV5V/1lPq4VeJ+M13s+ZW/GkfFCHPuDcZqfBYJCndNOg0ODDKda47UvngoGgueLyDWm2EG0dw6o1CBN26cX8gDMrKgb0UaJetay+CaBtC4dSoDlXf9wMWb6yjOm5E/tlgAOmsLqUJvmZ4pTaUUDLVVVZHpHmECDZ7lUit2plfGQTb4BJogAlXbKZLqbxZnxjLqGrl0FiydOFX3nVh7KmMyn1PITS9OUksI7gPZaflmPbXlQ3TtmvzvceY3T7fAkIqc4pb5lm4cPafeWKk+TOnmNX7VpZSi+iCMrDJeU+DOkJYtRD/r42dbo5QdAtn01DEfj3mUJ7cZ5n5fRz9p3A3tdi4usp8k+8myEXmb X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >> Is there any reson this notifier is still needed? I'd assume we can just allow >> for offlining + re-onlining as we please now. >> >> In fact, I'd assume we can get rid of the notifier entirely now? > > I was initially uncertain about contains_standby_increment() use case > and didnt change it here. However, after testing by removing the > contains_standby_increment() checks, I observed that the common memory > hotplug code already prevents offlining a memory block that contains > holes. This ensures safety without relying on these checks. > > c5e79ef561b0 ("mm/memory_hotplug.c: don't allow to online/offline memory blocks with holes") Rings a bell :) > > i.e. #cp define storage 3504M standby 2148M > This leads to a configuration where memory block 27 contains both > assigned and standby incr. > > But, offlining it will not succeed: > chmem -d 0x00000000d8000000-0x00000000dfffffff > chmem: Memory Block 27 (0x00000000d8000000-0x00000000dfffffff) disable > failed: Invalid argument > > Hence, I will remove it. Thanks. Cool! > >>> - case MEM_PREPARE_ONLINE: >>> - /* >>> - * Access the altmap_start_pfn and altmap_nr_pages fields >>> - * within the struct memory_notify specifically when dealing >>> - * with only MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers. >>> - * >>> - * When altmap is in use, take the specified memory range >>> - * online, which includes the altmap. >>> - */ >>> - if (arg->altmap_nr_pages) { >>> - start = PFN_PHYS(arg->altmap_start_pfn); >>> - size += PFN_PHYS(arg->altmap_nr_pages); >>> - } >>> - rc = sclp_mem_change_state(start, size, 1); >>> - if (rc || !arg->altmap_nr_pages) >>> - break; >>> - /* >>> - * Set CMMA state to nodat here, since the struct page memory >>> - * at the beginning of the memory block will not go through the >>> - * buddy allocator later. >>> - */ >>> - __arch_set_page_nodat((void *)__va(start), arg->altmap_nr_pages); >>> + default: >>> break; >>> - case MEM_FINISH_OFFLINE: >>> + } >>> + return rc ? NOTIFY_BAD : NOTIFY_OK; >>> +} >>> + >>> +static ssize_t config_mblock_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) >>> +{ >>> + struct mblock *mblock = container_of(kobj, struct mblock, kobj); >>> + >>> + return sysfs_emit(buf, "%u\n", READ_ONCE(mblock->config)); >>> +} >>> + >>> +static ssize_t config_mblock_store(struct kobject *kobj, struct kobj_attribute *attr, >>> + const char *buf, size_t count) >>> +{ >>> + unsigned long long addr, block_size; >> >> "unsigned long" should be sufficient I'm sure :) > > Left over. I will do so. > >>> + struct memory_block *mem; >>> + struct mblock *mblock; >>> + unsigned char id; >>> + bool value; >>> + int rc; >>> + >>> + rc = kstrtobool(buf, &value); >>> + if (rc) >>> + return rc; >>> + mblock = container_of(kobj, struct mblock, kobj); >>> + block_size = memory_block_size_bytes(); >>> + addr = mblock->id * block_size; >>> + /* >>> + * Hold device_hotplug_lock when adding/removing memory blocks. >>> + * Additionally, also protect calls to find_memory_block() and >>> + * sclp_attach_storage(). >>> + */ >>> + rc = lock_device_hotplug_sysfs(); >>> + if (rc) >>> + goto out; >>> + for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1) >>> + sclp_attach_storage(id); >>> + if (value) { >>> + if (mblock->config) >>> + goto out_unlock; >>> + rc = sclp_mem_change_state(addr, block_size, 1); >>> + if (rc) >>> + goto out_unlock; >>> /* >>> - * When altmap is in use, take the specified memory range >>> - * offline, which includes the altmap. >>> + * Set entire memory block CMMA state to nodat. Later, when >>> + * page tables pages are allocated via __add_memory(), those >>> + * regions are marked __arch_set_page_dat(). >>> */ >>> - if (arg->altmap_nr_pages) { >>> - start = PFN_PHYS(arg->altmap_start_pfn); >>> - size += PFN_PHYS(arg->altmap_nr_pages); >>> + __arch_set_page_nodat((void *)__va(addr), block_size >> PAGE_SHIFT); >>> + rc = __add_memory(0, addr, block_size, >>> + mblock->memmap_on_memory ? >>> + MHP_MEMMAP_ON_MEMORY | MHP_OFFLINE_INACCESSIBLE : MHP_NONE); >>> + if (rc) >>> + goto out_unlock; >> >> Do we have to undo the state change? > > Intention was to keep error handling simple. In case of failure in > add_memory(), we would have state set to 1 (not given back). But, > subsequent configuration request for that block will not have an impact. I mean, if we can cleanup easily here by doing another sclp_mem_change_state(), I think we should just do that. I'd assume that sclp_mem_change_state() to 0 will usually not fail (I might be wrong :) ). [...] >>> -static int __init sclp_detect_standby_memory(void) >>> +static int __init sclp_setup_memory(void) >>> { >>> struct read_storage_sccb *sccb; >>> int i, id, assigned, rc; >>> + struct mblock *mblocks; >>> + struct kset *kset; >>> /* No standby memory in kdump mode */ >>> if (oldmem_data.start) >> >> Wouldn't we still want to create the ones for initial memory at least? > > Intention was the following: > configuration and deconfiguration of memory with optional > memmap-on-memory is mostly needed for only standby memory. > > If standby memory is absent or sclp is unavailable, we continue using > the previous behavior (only software offline/online), since the sclp > memory notifier was not registered in that case before either. I mean, probably nobody in the kdump kernel cares about it either way, agreed. -- Cheers David / dhildenb