- Feb 23, 2024
-
-
Yosry Ahmed authored
Patch series "mm: zswap: simplify zswap_swapoff()", v2. These patches aim to simplify zswap_swapoff() by removing the unnecessary trees cleanup code. Patch 1 makes sure that the order of operations during swapoff is enforced correctly, making sure the simplification in patch 2 is correct in a future-proof manner. This patch (of 2): In swap_range_free(), we update inuse_pages then do some cleanups (arch invalidation, zswap invalidation, swap cache cleanups, etc). During swapoff, try_to_unuse() checks that inuse_pages is 0 to make sure all swap entries are freed. Make sure we only update inuse_pages after we are done with the cleanups in swap_range_free(), and use the proper memory barriers to enforce it. This makes sure that code following try_to_unuse() can safely assume that swap_range_free() ran for all entries in thr swapfile (e.g. swap cache cleanup, zswap_swapoff()). In practice, this currently isn't a problem because swap_range_free() is called with the swap info lock held, and the swapoff code happens to spin for that after try_to_unuse(). However, this seems fragile and unintentional, so make it more relable and future-proof. This also facilitates a following simplification of zswap_swapoff(). Link: https://lkml.kernel.org/r/20240124045113.415378-1-yosryahmed@google.com Link: https://lkml.kernel.org/r/20240124045113.415378-2-yosryahmed@google.com Signed-off-by:
Yosry Ahmed <yosryahmed@google.com> Reviewed-by:
"Huang, Ying" <ying.huang@intel.com> Cc: Chengming Zhou <zhouchengming@bytedance.com> Cc: Chris Li <chrisl@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nhat Pham <nphamcs@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
-
Chengming Zhou authored
Each swapfile has one rb-tree to search the mapping of swp_entry_t to zswap_entry, that use a spinlock to protect, which can cause heavy lock contention if multiple tasks zswap_store/load concurrently. Optimize the scalability problem by splitting the zswap rb-tree into multiple rb-trees, each corresponds to SWAP_ADDRESS_SPACE_PAGES (64M), just like we did in the swap cache address_space splitting. Although this method can't solve the spinlock contention completely, it can mitigate much of that contention. Below is the results of kernel build in tmpfs with zswap shrinker enabled: linux-next zswap-lock-optimize real 1m9.181s 1m3.820s user 17m44.036s 17m40.100s sys 7m37.297s 4m54.622s So there are clearly improvements. Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-2-b5cc55479090@bytedance.com Signed-off-by:Chengming Zhou <zhouchengming@bytedance.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Acked-by:
Nhat Pham <nphamcs@gmail.com> Acked-by:
-
Chengming Zhou authored
Patch series "mm/zswap: optimize the scalability of zswap rb-tree", v2. When testing the zswap performance by using kernel build -j32 in a tmpfs directory, I found the scalability of zswap rb-tree is not good, which is protected by the only spinlock. That would cause heavy lock contention if multiple tasks zswap_store/load concurrently. So a simple solution is to split the only one zswap rb-tree into multiple rb-trees, each corresponds to SWAP_ADDRESS_SPACE_PAGES (64M). This idea is from the commit 4b3ef9da ("mm/swap: split swap cache into 64MB trunks"). Although this method can't solve the spinlock contention completely, it can mitigate much of that contention. Below is the results of kernel build in tmpfs with zswap shrinker enabled: linux-next zswap-lock-optimize real 1m9.181s 1m3.820s user 17m44.036s 17m40.100s sys 7m37.297s 4m54.622s So there are clearly improvements. And it's complementary with the ongoing zswap xarray conversion by Chris. Anyway, I think we can also merge this first, it's complementary IMHO. So I just refresh and resend this for further discussion. This patch (of 2): Not all zswap interfaces can handle the absence of the zswap rb-tree, actually only zswap_store() has handled it for now. To make things simple, we make sure each swapfile always have the zswap rb-tree prepared before being enabled and used. The preparation is unlikely to fail in practice, this patch just make it explicit. Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-0-b5cc55479090@bytedance.com Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-1-b5cc55479090@bytedance.com Signed-off-by:
-
Lukas Bulwahn authored
Commit 2cafb582 ("mempolicy: remove confusing MPOL_MF_LAZY dead code") removes MPOL_MF_LAZY handling in queue_pages_test_walk(), and with that, there is no effective use of the local variable endvma in that function remaining. Remove the local variable endvma and its dead code. No functional change. This issue was identified with clang-analyzer's dead stores analysis. Link: https://lkml.kernel.org/r/20240122092504.18377-1-lukas.bulwahn@gmail.com Signed-off-by:
Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
-
Lukas Bulwahn authored
The local variables r_tmp and l_tmp in mast_spanning_rebalance() are already initialized at its declaration; there is no need to assign the value again. Remove the duplicate initialization of {r,l}_tmp. No functional change. Due to common compiler optimizations, also no change to object code. This issue was identified with clang-analyzer's dead stores analysis. Link: https://lkml.kernel.org/r/20240122102000.29558-1-lukas.bulwahn@gmail.com Signed-off-by:Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by:
-
Nico Pache authored
When running with CATEGORY= (thp | hugetlb) we see a large numbers of tests failing. These failures are due to not being able to allocate a hugepage and normally occur on memory contrainted systems or when using large page sizes. drop_cache and compact_memory before the tests for a higher chance at a successful hugepage allocation. Link: https://lkml.kernel.org/r/20240117180037.15734-1-npache@redhat.com Signed-off-by:
Nico Pache <npache@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
-
Lokesh Gidra authored
To be consistent with other uffd ioctl's returning EAGAIN when mmap_changing is detected, we should change UFFDIO_MOVE to do the same. Link: https://lkml.kernel.org/r/20240117223922.1445327-1-lokeshgidra@google.com Signed-off-by:
Lokesh Gidra <lokeshgidra@google.com> Acked-by:
Suren Baghdasaryan <surenb@google.com> Acked-by:
Mike Rapoport (IBM) <rppt@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nicolas Geoffray <ngeoffray@google.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by:
-
Greg Thelen authored
Commit 32d118ad ("selftests/memfd: add tests for F_SEAL_EXEC"): - added several unused 'nbytes' local variables Commit 6469b66e ("selftests: improve vm.memfd_noexec sysctl tests"): - orphaned 'newpid_thread_fn2()' forward declaration - orphaned 'join_newpid_thread()' forward declaration - added unused 'pid' local in sysctl_simple_child() - orphaned 'fd' local in sysctl_simple_child() - added unused 'fd' in sysctl_nested_child() Delete the unused locals and forward declarations. Link: https://lkml.kernel.org/r/20240118095057.677544-1-gthelen@google.com Signed-off-by:
Greg Thelen <gthelen@google.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Daniel Verkamp <dverkamp@chromium.org> Cc: Jeff Xu <jeffxu@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
-
Shakeel Butt authored
One of our workloads (Postgres 14) has regressed when migrated from 5.10 to 6.1 upstream kernel. The regression can be reproduced by sysbench's oltp_write_only benchmark. It seems like the always on rstat flush in mem_cgroup_wb_stats() is causing the regression. So, rate limit that specific rstat flush. One potential consequence would be the dirty throttling might be decided on stale memcg stats. However from our benchmarks and production traffic we have not observed any change in the dirty throttling behavior of the application. Link: https://lkml.kernel.org/r/20240118184235.618164-1-shakeelb@google.com Fixes: 2d146aa3 ("mm: memcontrol: switch to rstat") Signed-off-by:
Shakeel Butt <shakeelb@google.com> Acked-by:
Roman Gushchin <roman.gushchin@linux.dev> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
-
Kefeng Wang authored
The GFP flags from vma_thp_gfp_mask() according to user configuration only used for large folio allocation but not for memory cgroup charge, and GFP_KERNEL is used for both order-0 and large order folio when memory cgroup charge at present. However, mem_cgroup_charge() uses the GFP flags in a fairly sophisticated way. In addition to checking gfpflags_allow_blocking(), it pays attention to __GFP_NORETRY and __GFP_RETRY_MAYFAIL to ensure that processes within this memcg do not exceed their quotas. So we'd better to move mem_cgroup_charge() into alloc_anon_folio(), 1) it will make us to allocate as much as possible large order folio, because we could try the next order if mem_cgroup_charge() fails, although the memcg's memory usage is close to its limits. 2) using same GFP flags for allocation and charge is to be consistent with PMD THP firstly, in addition, according to GFP flag returned from vma_thp_gfp_mask(), GFP_TRANSHUGE_LIGHT could make us skip direct reclaim, _GFP_NORETRY will make us skip mem_cgroup_oom() and won't trigger memory cgroup oom from large order(order <= COSTLY_ORDER) folio charging. Link: https://lkml.kernel.org/r/20240122011612.501029-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240117103954.2756050-1-wangkefeng.wang@huawei.com Signed-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by:
Ryan Roberts <ryan.roberts@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by:
-
Ryan Roberts authored
With the proliferation of large folios for file-backed memory, and more recently the introduction of multi-size THP for anonymous memory, it is becoming useful to be able to see exactly how large folios are mapped into processes. For some architectures (e.g. arm64), if most memory is mapped using contpte-sized and -aligned blocks, TLB usage can be optimized so it's useful to see where these requirements are and are not being met. thpmaps is a Python utility that reads /proc/<pid>/smaps, /proc/<pid>/pagemap and /proc/kpageflags to print information about how transparent huge pages (both file and anon) are mapped to a specified process or cgroup. It aims to help users debug and optimize their workloads. In future we may wish to introduce stats directly into the kernel (e.g. smaps or similar), but for now this provides a short term solution without the need to introduce any new ABI. Run with help option for a full listing of the arguments: # ./t... -
Ronald Monthero authored
The core-api create_workqueue is deprecated, this patch replaces the create_workqueue with alloc_workqueue. The previous implementation workqueue of zswap was a bounded workqueue, this patch uses alloc_workqueue() to create an unbounded workqueue. The WQ_UNBOUND attribute is desirable making the workqueue not localized to a specific cpu so that the scheduler is free to exercise improvisations in any demanding scenarios for offloading cpu time slices for workqueues. For example if any other workqueues of the same primary cpu had to be served which are WQ_HIGHPRI and WQ_CPU_INTENSIVE. Also Unbound workqueue happens to be more efficient in a system during memory pressure scenarios in comparison to a bounded workqueue. shrink_wq = alloc_workqueue("zswap-shrink", WQ_UNBOUND|WQ_MEM_RECLAIM, 1); Overall the change suggested in this patch should be seamless and does not alter the existing behavior, other than the improvisation to be an unbounded workqueue. Link: https://lkml.kernel.org/r/20240116133145.12454-1-debug.penguin32@gmail.com Signed-off-by:Ronald Monthero <debug.penguin32@gmail.com> Acked-by:
-
Pankaj Raghav authored
A while loop is used to adjust the new_order to be lower than the ra->size. ilog2 could be used to do the same instead of using a loop. ilog2 typically resolves to a bit scan reverse instruction. This is particularly useful when ra->size is smaller than the 2^new_order as it resolves in one instruction instead of looping to find the new_order. No functional changes. Link: https://lkml.kernel.org/r/20240115102523.2336742-1-kernel@pankajraghav.com Signed-off-by:
Pankaj Raghav <p.raghav@samsung.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
-
- Feb 22, 2024
-
-
Hui Zhu authored
Function parameter addr of add_to_pagemap() is useless. Remove it. Link: https://lkml.kernel.org/r/20240111084533.40038-1-teawaterz@linux.alibaba.com Signed-off-by:
Hui Zhu <teawater@antgroup.com> Reviewed-by:
Muhammad Usama Anjum <usama.anjum@collabora.com> Tested-by:
-
Kefeng Wang authored
Now all callers of mm_counter_file() have a folio, convert mm_counter_file() to take a folio. Saves a call to compound_head() hidden inside PageSwapBacked(). Link: https://lkml.kernel.org/r/20240111152429.3374566-11-willy@infradead.org Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Signed-off-by:
-
Kefeng Wang authored
Now all callers of mm_counter() have a folio, convert mm_counter() to take a folio. Saves a call to compound_head() hidden inside PageAnon(). Link: https://lkml.kernel.org/r/20240111152429.3374566-10-willy@infradead.org Signed-off-by:
-
Kefeng Wang authored
Make should_zap_page() take a folio and rename it to should_zap_folio() as preparation for converting mm counter functions to take a folio. Saves a call to compound_head() hidden inside PageAnon(). [wangkefeng.wang@huawei.com: fix used-uninitialized warning] Link: https://lkml.kernel.org/r/962a7993-fce9-4de8-85cd-25e290f25736@huawei.com Link: https://lkml.kernel.org/r/20240111152429.3374566-9-willy@infradead.org Signed-off-by:
-
Kefeng Wang authored
Call pfn_swap_entry_folio() as preparation for converting mm counter functions to take a folio. Link: https://lkml.kernel.org/r/20240111152429.3374566-8-willy@infradead.org Signed-off-by:
-
Kefeng Wang authored
Call pfn_swap_entry_to_folio() in zap_huge_pmd() as preparation for converting mm counter functions to take a folio. Saves a call to compound_head() embedded inside PageAnon(). Link: https://lkml.kernel.org/r/20240111152429.3374566-7-willy@infradead.org Signed-off-by:
-
Kefeng Wang authored
Call pfn_swap_entry_folio() in __split_huge_pmd_locked() as preparation for converting mm counter functions to take a folio. Link: https://lkml.kernel.org/r/20240111152429.3374566-6-willy@infradead.org Signed-off-by:
-
Kefeng Wang authored
Call pfn_swap_entry_folio() in ptep_zap_swap_entry() as preparation for converting mm counter functions to take a folio. Link: https://lkml.kernel.org/r/20240111152429.3374566-5-willy@infradead.org Signed-off-by:
-
Matthew Wilcox (Oracle) authored
We only want to know whether the folio is anonymous, so use pfn_swap_entry_folio() and save a call to compound_head(). Link: https://lkml.kernel.org/r/20240111152429.3374566-4-willy@infradead.org Signed-off-by:
-
Matthew Wilcox (Oracle) authored
These callers only pass the result to PageAnon(), so we can save the extra call to compound_head() by using pfn_swap_entry_folio(). Link: https://lkml.kernel.org/r/20240111152429.3374566-3-willy@infradead.org Signed-off-by:
-
Matthew Wilcox (Oracle) authored
Patch series "mm: convert mm counter to take a folio", v3. Make sure all mm_counter() and mm_counter_file() callers have a folio, then convert mm counter functions to take a folio, which saves some compound_head() calls. This patch (of 10): Thanks to the compound_head() hidden inside PageLocked(), this saves a call to compound_head() over calling page_folio(pfn_swap_entry_to_page()) Link: https://lkml.kernel.org/r/20240111152429.3374566-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240111152429.3374566-2-willy@infradead.org Signed-off-by:
-
Matthew Wilcox (Oracle) authored
Replace five calls to compound_head() with one. Link: https://lkml.kernel.org/r/20240111181219.3462852-5-willy@infradead.org Signed-off-by:
Muchun Song <muchun.song@linux.dev> Acked-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
-
Matthew Wilcox (Oracle) authored
Replace seven calls to compound_head() with one. We still use the page as page_mapped() is different from folio_mapped(). Link: https://lkml.kernel.org/r/20240111181219.3462852-4-willy@infradead.org Signed-off-by:
-
Matthew Wilcox (Oracle) authored
All users of target.page convert it to the folio, so we can just return the folio directly and save a few calls to compound_head(). Link: https://lkml.kernel.org/r/20240111181219.3462852-3-willy@infradead.org Signed-off-by:
-
Matthew Wilcox (Oracle) authored
Patch series "Convert memcontrol charge moving to use folios". No part of these patches should change behaviour; all the called functions already convert from page to folio, so this ought to simply be a reduction in the number of calls to compound_head(). This patch (of 4): Remove many calls to compound_head() by calling page_folio() once at the start of each stanza which receives a struct page from 'target'. There should be no change in behaviour here as all the called functions start out by converting the page to its folio. Link: https://lkml.kernel.org/r/20240111181219.3462852-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240111181219.3462852-2-willy@infradead.org Signed-off-by:
-
Yang Shi authored
We avoid allocating THP for temporary stack, even though khugepaged_enter_vma() is called for stack VMAs, it actualy returns false. So no need to call it in the first place at all. Link: https://lkml.kernel.org/r/20231221065943.2803551-1-shy828301@gmail.com Signed-off-by:
Yang Shi <yang@os.amperecomputing.com> Reviewed-by:
Yin Fengwei <fengwei.yin@intel.com> Cc: Christopher Lameter <cl@linux.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: kernel test robot <oliver.sang@intel.com> Signed-off-by:
-
Haifeng Xu authored
list_lru_init_key() isn't used by anyone, remove it to clean up. Link: https://lkml.kernel.org/r/20231228062715.338672-2-haifeng.xu@shopee.com Signed-off-by:
Haifeng Xu <haifeng.xu@shopee.com> Acked-by:
-
Haifeng Xu authored
Actually, when using a boot time kernel option "cgroup.memory=nokmem", all lru items are inserted to list_lru_node. But for those users who invoke list_lru_init_memcg() to initialize list_lru, list_lru_memcg_aware() returns true. And this brings unneeded operations related to memcg. To make things more convenient, let's disable memcg_aware when cgroup.memory is set to "nokmem". Link: https://lkml.kernel.org/r/20231228062715.338672-1-haifeng.xu@shopee.com Signed-off-by:
-
Kefeng Wang authored
The clear and copy of huge gigantic page has converted to use nth_page() to handle the possible discontinuous struct page(SPARSEMEM without VMEMMAP), but not change for the non-gigantic part, fix it too. Link: https://lkml.kernel.org/r/20231229082207.60235-1-wangkefeng.wang@huawei.com Signed-off-by:
-
Yajun Deng authored
The file parameter in the __remove_shared_vm_struct is no longer used, remove it. These functions vma_link() and mmap_region() have some of the same code, introduce vma_link_file() helper function to simplify the code. Link: https://lkml.kernel.org/r/20240110084622.2425927-1-yajun.deng@linux.dev Signed-off-by:
Yajun Deng <yajun.deng@linux.dev> Signed-off-by:
-
Kuan-Ying Lee authored
The patch series "Mitigate a vmap lock contention" removes vmap_area_list, which will break the gdb vmallocinfo command: (gdb) lx-vmallocinfo Python Exception <class 'gdb.error'>: No symbol "vmap_area_list" in current context. Error occurred in Python: No symbol "vmap_area_list" in current context. So we can instead use vmap_nodes to iterate all vmallocinfo. Link: https://lkml.kernel.org/r/20240207085856.11190-1-Kuan-Ying.Lee@mediatek.com Signed-off-by:
Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> Cc: Casper Li <casper.li@mediatek.com> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Cc: Chinwen Chang <chinwen.chang@mediatek.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by:
-
JP Kobryn authored
Replace some goto statements with return statements so that unmap() is not called on an undefined address. This change is made so that unmap() can only be reached after mmap() is called (and the address mentioned is defined). Returning MAP_FAILED seems acceptable since client code checks for this value. Link: https://lkml.kernel.org/r/20240105202401.28851-1-inwardvessel@gmail.com Fixes: 42096aa2 ("selftest/mm: ksm_functional_tests: test in mmap_and_merge_range() if anything got merged") Signed-off-by:
JP Kobryn <inwardvessel@gmail.com> Reviewed-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
-
Hongbo Li authored
The return type of function folio_test_hugetlb is bool type, there is no need to assign it to an integer type. Link: https://lkml.kernel.org/r/20240108044815.3291487-1-lihongbo22@huawei.com Signed-off-by:
Hongbo Li <lihongbo22@huawei.com> Reviewed-by:
-
Sumanth Korikkar authored
Enable MHP_MEMMAP_ON_MEMORY to support "memmap on memory". memory_hotplug.memmap_on_memory=true kernel parameter should be set in kernel boot option to enable the feature. Link: https://lkml.kernel.org/r/20240108132747.3238763-6-sumanthk@linux.ibm.com Reviewed-by:
Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by:
Sumanth Korikkar <sumanthk@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by:
-
Sumanth Korikkar authored
MEM_PREPARE_ONLINE memory notifier makes memory block physical accessible via sclp assign command. The notifier ensures self-contained memory maps are accessible and hence enabling the "memmap on memory" on s390. MEM_FINISH_OFFLINE memory notifier shifts the memory block to an inaccessible state via sclp unassign command. Implementation considerations: * When MHP_MEMMAP_ON_MEMORY is disabled, the system retains the old behavior. This means the memory map is allocated from default memory. * If MACHINE_HAS_EDAT1 is unavailable, MHP_MEMMAP_ON_MEMORY is automatically disabled. This ensures that vmemmap pagetables do not consume additional memory from the default memory allocator. * The MEM_GOING_ONLINE notifier has been modified to perform no operation, as MEM_PREPARE_ONLINE already executes the sclp assign command. * The MEM_CANCEL_ONLINE/MEM_OFFLINE notifier now performs no operation, as MEM_FINISH_OFFLINE already executes the sclp unassign command. Link: https://lkml.kernel.org/r/20240108132747.3238763-5-sumanthk@linux.ibm.com Reviewed-by:
-
Sumanth Korikkar authored
Remove memory notifier types which are unhandled by s390. Unhandled memory notifier types are covered by default case. Link: https://lkml.kernel.org/r/20240108132747.3238763-4-sumanthk@linux.ibm.com Suggested-by:
Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by:
-
Sumanth Korikkar authored
Allocate memory map (struct pages array) from the hotplugged memory range, rather than using system memory. The change addresses the issue where standby memory, when configured to be much larger than online memory, could potentially lead to ipl failure due to memory map allocation from online memory. For example, 16MB of memory map allocation is needed for a memory block size of 1GB and when standby memory is configured much larger than online memory, this could lead to ipl failure. To address this issue, the solution involves introducing "memmap on memory" using the vmem_altmap structure on s390. Architectures that want to implement it should pass the altmap to the vmemmap_populate() function and its associated callchain. This enhancement is discussed in commit 4b94ffdc ("x86, mm: introduce vmem_altmap to augment vmemmap_populate()") Provide "memmap on memory" support for s390 by passing the altmap in vmemmap_populate() and its callchain. The allocation path is described as follows: * When altmap is NULL in vmemmap_populate(), memory map allocation occurs using the existing vmemmap_alloc_block_buf(). * When altmap is not NULL in vmemmap_populate(), memory map allocation still uses vmemmap_alloc_block_buf(), but this function internally calls altmap_alloc_block_buf(). For deallocation, the process is outlined as follows: * When altmap is NULL in vmemmap_free(), memory map deallocation happens through free_pages(). * When altmap is not NULL in vmemmap_free(), memory map deallocation occurs via vmem_altmap_free(). While memory map allocation is primarily handled through the self-contained memory map range, there might still be a small amount of system memory allocation required for vmemmap pagetables. To mitigate this impact, this feature will be limited to machines with EDAT1 support. Link: https://lkml.kernel.org/r/20240108132747.3238763-3-sumanthk@linux.ibm.com Reviewed-by:
-
