- 26 Apr, 2024 40 commits
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Suren Baghdasaryan authored
Introduce helper functions to easily instrument page allocators by storing a pointer to the allocation tag associated with the code that allocated the page in a page_ext field. Link: https://lkml.kernel.org/r/20240321163705.3067592-15-surenb@google.comSigned-off-by:
Suren Baghdasaryan <surenb@google.com> Co-developed-by:
Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Tested-by:
Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andreas Hindborg <a.hindborg@samsung.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Gary Guo <gary@garyguo.net> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Suren Baghdasaryan authored
Introduce CONFIG_MEM_ALLOC_PROFILING which provides definitions to easily instrument memory allocators. It registers an "alloc_tags" codetag type with /proc/allocinfo interface to output allocation tag information when the feature is enabled. CONFIG_MEM_ALLOC_PROFILING_DEBUG is provided for debugging the memory allocation profiling instrumentation. Memory allocation profiling can be enabled or disabled at runtime using /proc/sys/vm/mem_profiling sysctl when CONFIG_MEM_ALLOC_PROFILING_DEBUG=n. CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT enables memory allocation profiling by default. [surenb@google.com: Documentation/filesystems/proc.rst: fix allocinfo title] Link: https://lkml.kernel.org/r/20240326073813.727090-1-surenb@google.com [surenb@google.com: do limited memory accounting for modules with ARCH_NEEDS_WEAK_PER_CPU] Link: https://lkml.kernel.org/r/20240402180933.1663992-2-surenb@google.com [klarasmodin@gmail.com: explicitly include irqflags.h in alloc_tag.h] Link: https://lkml.kernel.org/r/20240407133252.173636-1-klarasmodin@gmail.com [surenb@google.com: fix alloc_tag_init() to prevent passing NULL to PTR_ERR()] Link: https://lkml.kernel.org/r/20240417003349.2520094-1-surenb@google.com Link: https://lkml.kernel.org/r/20240321163705.3067592-14-surenb@google.comSigned-off-by:
Klara Modin <klarasmodin@gmail.com> Tested-by:
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Suren Baghdasaryan authored
Skip freeing module's data section if there are non-zero allocation tags because otherwise, once these allocations are freed, the access to their code tag would cause UAF. Link: https://lkml.kernel.org/r/20240321163705.3067592-13-surenb@google.comSigned-off-by:
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Suren Baghdasaryan authored
Add support for code tagging from dynamically loaded modules. Link: https://lkml.kernel.org/r/20240321163705.3067592-12-surenb@google.comSigned-off-by:
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Suren Baghdasaryan authored
Add basic infrastructure to support code tagging which stores tag common information consisting of the module name, function, file name and line number. Provide functions to register a new code tag type and navigate between code tags. Link: https://lkml.kernel.org/r/20240321163705.3067592-11-surenb@google.comCo-developed-by:
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Suren Baghdasaryan authored
Introduce objext_flags to store additional objext flags unrelated to memcg. Link: https://lkml.kernel.org/r/20240321163705.3067592-10-surenb@google.comSigned-off-by:
Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by:
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Suren Baghdasaryan authored
Slab extension objects can't be allocated before slab infrastructure is initialized. Some caches, like kmem_cache and kmem_cache_node, are created before slab infrastructure is initialized. Objects from these caches can't have extension objects. Introduce SLAB_NO_OBJ_EXT slab flag to mark these caches and avoid creating extensions for objects allocated from these slabs. Link: https://lkml.kernel.org/r/20240321163705.3067592-9-surenb@google.comSigned-off-by:
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Suren Baghdasaryan authored
Introduce __GFP_NO_OBJ_EXT flag in order to prevent recursive allocations when allocating slabobj_ext on a slab. Link: https://lkml.kernel.org/r/20240321163705.3067592-8-surenb@google.comSigned-off-by:
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Suren Baghdasaryan authored
Currently slab pages can store only vectors of obj_cgroup pointers in page->memcg_data. Introduce slabobj_ext structure to allow more data to be stored for each slab object. Wrap obj_cgroup into slabobj_ext to support current functionality while allowing to extend slabobj_ext in the future. Link: https://lkml.kernel.org/r/20240321163705.3067592-7-surenb@google.comSigned-off-by:
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Kent Overstreet authored
We're introducing alloc tagging, which tracks memory allocations by callsite. Converting alloc_inode_sb() to a macro means allocations will be tracked by its caller, which is a bit more useful. Link: https://lkml.kernel.org/r/20240321163705.3067592-6-surenb@google.comSigned-off-by:
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Kent Overstreet authored
These symbols are used to denote section boundaries: by always including them we can unify loading sections from modules with loading built-in sections, which leads to some significant cleanup. Link: https://lkml.kernel.org/r/20240321163705.3067592-5-surenb@google.comSigned-off-by:
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Kent Overstreet authored
It seems we need to be more forceful with the compiler on this one. This is done for performance reasons only. Link: https://lkml.kernel.org/r/20240321163705.3067592-4-surenb@google.comSigned-off-by:
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Kent Overstreet authored
Needed to avoid a new circular dependency with the memory allocation profiling series. Naturally, a whole bunch of files needed to include vmalloc.h that were previously getting it implicitly. Link: https://lkml.kernel.org/r/20240321163705.3067592-3-surenb@google.comSigned-off-by:
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Kent Overstreet authored
Patch series "Memory allocation profiling", v6. Overview: Low overhead [1] per-callsite memory allocation profiling. Not just for debug kernels, overhead low enough to be deployed in production. Example output: root@moria-kvm:~# sort -rn /proc/allocinfo 127664128 31168 mm/page_ext.c:270 func:alloc_page_ext 56373248 4737 mm/slub.c:2259 func:alloc_slab_page 14880768 3633 mm/readahead.c:247 func:page_cache_ra_unbounded 14417920 3520 mm/mm_init.c:2530 func:alloc_large_system_hash 13377536 234 block/blk-mq.c:3421 func:blk_mq_alloc_rqs 11718656 2861 mm/filemap.c:1919 func:__filemap_get_folio 9192960 2800 kernel/fork.c:307 func:alloc_thread_stack_node 4206592 4 net/netfilter/nf_conntrack_core.c:2567 func:nf_ct_alloc_hashtable 4136960 1010 drivers/staging/ctagmod/ctagmod.c:20 [ctagmod] func:ctagmod_start 3940352 962 mm/memory.c:4214 func:alloc_anon_folio 2894464 22613 fs/kernfs/dir.c:615 func:__kernfs_new_node ... Usage: kconfig options: - CONFIG_MEM_ALLOC_PROFILING - CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT - CONFIG_MEM_ALLOC_PROFILING_DEBUG adds warnings for allocations that weren't accounted because of a missing annotation sysctl: /proc/sys/vm/mem_profiling Runtime info: /proc/allocinfo Notes: [1]: Overhead To measure the overhead we are comparing the following configurations: (1) Baseline with CONFIG_MEMCG_KMEM=n (2) Disabled by default (CONFIG_MEM_ALLOC_PROFILING=y && CONFIG_MEM_ALLOC_PROFILING_BY_DEFAULT=n) (3) Enabled by default (CONFIG_MEM_ALLOC_PROFILING=y && CONFIG_MEM_ALLOC_PROFILING_BY_DEFAULT=y) (4) Enabled at runtime (CONFIG_MEM_ALLOC_PROFILING=y && CONFIG_MEM_ALLOC_PROFILING_BY_DEFAULT=n && /proc/sys/vm/mem_profiling=1) (5) Baseline with CONFIG_MEMCG_KMEM=y && allocating with __GFP_ACCOUNT (6) Disabled by default (CONFIG_MEM_ALLOC_PROFILING=y && CONFIG_MEM_ALLOC_PROFILING_BY_DEFAULT=n) && CONFIG_MEMCG_KMEM=y (7) Enabled by default (CONFIG_MEM_ALLOC_PROFILING=y && CONFIG_MEM_ALLOC_PROFILING_BY_DEFAULT=y) && CONFIG_MEMCG_KMEM=y Performance overhead: To evaluate performance we implemented an in-kernel test executing multiple get_free_page/free_page and kmalloc/kfree calls with allocation sizes growing from 8 to 240 bytes with CPU frequency set to max and CPU affinity set to a specific CPU to minimize the noise. Below are results from running the test on Ubuntu 22.04.2 LTS with 6.8.0-rc1 kernel on 56 core Intel Xeon: kmalloc pgalloc (1 baseline) 6.764s 16.902s (2 default disabled) 6.793s (+0.43%) 17.007s (+0.62%) (3 default enabled) 7.197s (+6.40%) 23.666s (+40.02%) (4 runtime enabled) 7.405s (+9.48%) 23.901s (+41.41%) (5 memcg) 13.388s (+97.94%) 48.460s (+186.71%) (6 def disabled+memcg) 13.332s (+97.10%) 48.105s (+184.61%) (7 def enabled+memcg) 13.446s (+98.78%) 54.963s (+225.18%) Memory overhead: Kernel size: text data bss dec diff (1) 26515311 18890222 17018880 62424413 (2) 26524728 19423818 16740352 62688898 264485 (3) 26524724 19423818 16740352 62688894 264481 (4) 26524728 19423818 16740352 62688898 264485 (5) 26541782 18964374 16957440 62463596 39183 Memory consumption on a 56 core Intel CPU with 125GB of memory: Code tags: 192 kB PageExts: 262144 kB (256MB) SlabExts: 9876 kB (9.6MB) PcpuExts: 512 kB (0.5MB) Total overhead is 0.2% of total memory. Benchmarks: Hackbench tests run 100 times: hackbench -s 512 -l 200 -g 15 -f 25 -P baseline disabled profiling enabled profiling avg 0.3543 0.3559 (+0.0016) 0.3566 (+0.0023) stdev 0.0137 0.0188 0.0077 hackbench -l 10000 baseline disabled profiling enabled profiling avg 6.4218 6.4306 (+0.0088) 6.5077 (+0.0859) stdev 0.0933 0.0286 0.0489 stress-ng tests: stress-ng --class memory --seq 4 -t 60 stress-ng --class cpu --seq 4 -t 60 Results posted at: https://evilpiepirate.org/~kent/memalloc_prof_v4_stress-ng/ [2] https://lore.kernel.org/all/20240306182440.2003814-1-surenb@google.com/ This patch (of 37): The next patch drops vmalloc.h from a system header in order to fix a circular dependency; this adds it to all the files that were pulling it in implicitly. [kent.overstreet@linux.dev: fix arch/alpha/lib/memcpy.c] Link: https://lkml.kernel.org/r/20240327002152.3339937-1-kent.overstreet@linux.dev [surenb@google.com: fix arch/x86/mm/numa_32.c] Link: https://lkml.kernel.org/r/20240402180933.1663992-1-surenb@google.com [kent.overstreet@linux.dev: a few places were depending on sizes.h] Link: https://lkml.kernel.org/r/20240404034744.1664840-1-kent.overstreet@linux.dev [arnd@arndb.de: fix mm/kasan/hw_tags.c] Link: https://lkml.kernel.org/r/20240404124435.3121534-1-arnd@kernel.org [surenb@google.com: fix arc build] Link: https://lkml.kernel.org/r/20240405225115.431056-1-surenb@google.com Link: https://lkml.kernel.org/r/20240321163705.3067592-1-surenb@google.com Link: https://lkml.kernel.org/r/20240321163705.3067592-2-surenb@google.comSigned-off-by:Arnd Bergmann <arnd@arndb.de> Reviewed-by:
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Randy Dunlap authored
Memory profiling introduces macros as hooks for function-level allocation profiling[1]. Memory allocation functions that are profiled are named like xyz_alloc() for API access to the function. xyz_alloc() then calls xyz_alloc_noprof() to do the allocation work. The kernel-doc comments for the memory allocation functions are introduced with the xyz_alloc() function names but the function implementations are the xyz_alloc_noprof() names. This causes kernel-doc warnings for mismatched documentation and function prototype names. By dropping the "_noprof" part of the function name, the kernel-doc function name matches the function prototype name, so the warnings are resolved. [1] https://lore.kernel.org/all/20240321163705.3067592-1-surenb@google.com/ Link: https://lkml.kernel.org/r/20240326054149.2121-1-rdunlap@infradead.orgSigned-off-by:
Randy Dunlap <rdunlap@infradead.org> Reported-by:
Stephen Rothwell <sfr@canb.auug.org.au> Closes: https://lore.kernel.org/all/20240325123603.1bdd6588@canb.auug.org.au/Tested-by:
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Yosry Ahmed authored
In pcpu_map_pages(), if __pcpu_map_pages() fails on a CPU, we call __pcpu_unmap_pages() to clean up mappings on all CPUs where mappings were created, but not on the CPU where __pcpu_map_pages() fails. __pcpu_map_pages() and __pcpu_unmap_pages() are wrappers around vmap_pages_range_noflush() and vunmap_range_noflush(). All other callers of vmap_pages_range_noflush() call vunmap_range_noflush() when mapping fails, except pcpu_map_pages(). The reason could be that partial mappings may be left behind from a failed mapping attempt. Call __pcpu_unmap_pages() for the failed CPU as well in pcpu_map_pages(). This was found by code inspection, no failures or bugs were observed. Link: https://lkml.kernel.org/r/20240311194346.2291333-1-yosryahmed@google.comSigned-off-by:
Yosry Ahmed <yosryahmed@google.com> Acked-by:
Dennis Zhou <dennis@kernel.org> Cc: Christoph Lameter (Ampere) <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
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Donet Tom authored
commit bda420b9 ("numa balancing: migrate on fault among multiple bound nodes") added support for migrate on protnone reference with MPOL_BIND memory policy. This allowed numa fault migration when the executing node is part of the policy mask for MPOL_BIND. This patch extends migration support to MPOL_PREFERRED_MANY policy. Currently, we cannot specify MPOL_PREFERRED_MANY with the mempolicy flag MPOL_F_NUMA_BALANCING. This causes issues when we want to use NUMA_BALANCING_MEMORY_TIERING. To effectively use the slow memory tier, the kernel should not allocate pages from the slower memory tier via allocation control zonelist fallback. Instead, we should move cold pages from the faster memory node via memory demotion. For a page allocation, kswapd is only woken up after we try to allocate pages from all nodes in the allocation zone list. This implies that, without using memory policies, we will end up allocating hot pages in the slower memory tier. MPOL_PREFERRED_MANY was added by commit b27abacc ("mm/mempolicy: add MPOL_PREFERRED_MANY for multiple preferred nodes") to allow better allocation control when we have memory tiers in the system. With MPOL_PREFERRED_MANY, the user can use a policy node mask consisting only of faster memory nodes. When we fail to allocate pages from the faster memory node, kswapd would be woken up, allowing demotion of cold pages to slower memory nodes. With the current kernel, such usage of memory policies implies we can't do page promotion from a slower memory tier to a faster memory tier using numa fault. This patch fixes this issue. For MPOL_PREFERRED_MANY, if the executing node is in the policy node mask, we allow numa migration to the executing nodes. If the executing node is not in the policy node mask, we do not allow numa migration. Example: On a 2-sockets system, NUMA node N0, N1 and N2 are in socket 0, N3 in socket 1. N0, N1 and N3 have fast memory and CPU, while N2 has slow memory and no CPU. For a workload, we may use MPOL_PREFERRED_MANY with nodemask N0 and N1 set because the workload runs on CPUs of socket 0 at most times. Then, even if the workload runs on CPUs of N3 occasionally, we will not try to migrate the workload pages from N2 to N3 because users may want to avoid cross-socket access as much as possible in the long term. In below table, Process is the Process executing node and Curr Loc Pgs is the numa node where page present(folio node) =========================================================== Process Policy Curr Loc Pgs Observation ----------------------------------------------------------- N0 N0 N1 N1 Pages Migrated from N1 to N0 N0 N0 N1 N2 Pages Migrated from N2 to N0 N0 N0 N1 N3 Pages Migrated from N3 to N0 N3 N0 N1 N0 Pages NOT Migrated to N3 N3 N0 N1 N1 Pages NOT Migrated to N3 N3 N0 N1 N2 Pages NOT Migrated to N3 ------------------------------------------------------------ Link: https://lkml.kernel.org/r/158acc57319129aa46d50fd64c9330f3e7c7b4bf.1711373653.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/369d6a58758396335fd1176d97bbca4e7730d75a.1709909210.git.donettom@linux.ibm.comSigned-off-by:
Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Signed-off-by:
Donet Tom <donettom@linux.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Huang, Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
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Donet Tom authored
Patch series "Allow migrate on protnone reference with MPOL_PREFERRED_MANY policy:, v4. This patchset is to optimize the cross-socket memory access with MPOL_PREFERRED_MANY policy. To test this patch we ran the following test on a 3 node system. Node 0 - 2GB - Tier 1 Node 1 - 11GB - Tier 1 Node 6 - 10GB - Tier 2 Below changes are made to memcached to set the memory policy, It select Node0 and Node1 as preferred nodes. #include <numaif.h> #include <numa.h> unsigned long nodemask; int ret; nodemask = 0x03; ret = set_mempolicy(MPOL_PREFERRED_MANY | MPOL_F_NUMA_BALANCING, &nodemask, 10); /* If MPOL_F_NUMA_BALANCING isn't supported, * fall back to MPOL_PREFERRED_MANY */ if (ret < 0 && errno == EINVAL){ printf("set mem policy normal\n"); ret = set_mempolicy(MPOL_PREFERRED_MANY, &nodemask, 10); } if (ret < 0) { perror("Failed to call set_mempolicy"); exit(-1); } Test Procedure: =============== 1. Make sure memory tiring and demotion are enabled. 2. Start memcached. # ./memcached -b 100000 -m 204800 -u root -c 1000000 -t 7 -d -s "/tmp/memcached.sock" 3. Run memtier_benchmark to store 3200000 keys. #./memtier_benchmark -S "/tmp/memcached.sock" --protocol=memcache_binary --threads=1 --pipeline=1 --ratio=1:0 --key-pattern=S:S --key-minimum=1 --key-maximum=3200000 -n allkeys -c 1 -R -x 1 -d 1024 4. Start a memory eater on node 0 and 1. This will demote all memcached pages to node 6. 5. Make sure all the memcached pages got demoted to lower tier by reading /proc/<memcaced PID>/numa_maps. # cat /proc/2771/numa_maps --- default anon=1009 dirty=1009 active=0 N6=1009 kernelpagesize_kB=64 default anon=1009 dirty=1009 active=0 N6=1009 kernelpagesize_kB=64 --- 6. Kill memory eater. 7. Read the pgpromote_success counter. 8. Start reading the keys by running memtier_benchmark. #./memtier_benchmark -S "/tmp/memcached.sock" --protocol=memcache_binary --pipeline=1 --distinct-client-seed --ratio=0:3 --key-pattern=R:R --key-minimum=1 --key-maximum=3200000 -n allkeys --threads=64 -c 1 -R -x 6 9. Read the pgpromote_success counter. Test Results: ============= Without Patch ------------------ 1. pgpromote_success before test Node 0: pgpromote_success 11 Node 1: pgpromote_success 140974 pgpromote_success after test Node 0: pgpromote_success 11 Node 1: pgpromote_success 140974 2. Memtier-benchmark result. AGGREGATED AVERAGE RESULTS (6 runs) ================================================================== Type Ops/sec Hits/sec Misses/sec Avg. Latency p50 Latency ------------------------------------------------------------------ Sets 0.00 --- --- --- --- Gets 305792.03 305791.93 0.10 0.18949 0.16700 Waits 0.00 --- --- --- --- Totals 305792.03 305791.93 0.10 0.18949 0.16700 ====================================== p99 Latency p99.9 Latency KB/sec ------------------------------------- --- --- 0.00 0.44700 1.71100 11542.69 --- --- --- 0.44700 1.71100 11542.69 With Patch --------------- 1. pgpromote_success before test Node 0: pgpromote_success 5 Node 1: pgpromote_success 89386 pgpromote_success after test Node 0: pgpromote_success 57895 Node 1: pgpromote_success 141463 2. Memtier-benchmark result. AGGREGATED AVERAGE RESULTS (6 runs) ==================================================================== Type Ops/sec Hits/sec Misses/sec Avg. Latency p50 Latency -------------------------------------------------------------------- Sets 0.00 --- --- --- --- Gets 521942.24 521942.07 0.17 0.11459 0.10300 Waits 0.00 --- --- --- --- Totals 521942.24 521942.07 0.17 0.11459 0.10300 ======================================= p99 Latency p99.9 Latency KB/sec --------------------------------------- --- --- 0.00 0.23100 0.31900 19701.68 --- --- --- 0.23100 0.31900 19701.68 Test Result Analysis: ===================== 1. With patch we could observe pages are getting promoted. 2. Memtier-benchmark results shows that, with the patch, performance has increased more than 50%. Ops/sec without fix - 305792.03 Ops/sec with fix - 521942.24 This patch (of 2): Instead of using 'cpu_to_node()', we use 'numa_node_id()', which is quicker. smp_processor_id is guaranteed to be stable in the 'mpol_misplaced()' function because it is called with ptl held. lockdep_assert_held was added to ensure that. No functional change in this patch. [donettom@linux.ibm.com: add "* @vmf: structure describing the fault" comment] Link: https://lkml.kernel.org/r/d8b993ea9dccfac0bc3ed61d3a81f4ac5f376e46.1711002865.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/cover.1711373653.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/6059f034f436734b472d066db69676fb3a459864.1711373653.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/cover.1709909210.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/744646531af02cc687cde8ae788fb1779e99d02c.1709909210.git.donettom@linux.ibm.comSigned-off-by: -
Yosry Ahmed authored
zswap_find_zpool() checks if ZSWAP_NR_ZPOOLS > 1, which is always true. This is a remnant from a patch version that had ZSWAP_NR_ZPOOLS as a config option and never made it upstream. Remove the unnecessary check. Link: https://lkml.kernel.org/r/20240311235210.2937484-1-yosryahmed@google.comSigned-off-by:
Chengming Zhou <chengming.zhou@linux.dev> Reviewed-by:
Nhat Pham <nphamcs@gmail.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by:
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Duoming Zhou authored
The kcalloc() in dmirror_device_evict_chunk() will return null if the physical memory has run out. As a result, if src_pfns or dst_pfns is dereferenced, the null pointer dereference bug will happen. Moreover, the device is going away. If the kcalloc() fails, the pages mapping a chunk could not be evicted. So add a __GFP_NOFAIL flag in kcalloc(). Finally, as there is no need to have physically contiguous memory, Switch kcalloc() to kvcalloc() in order to avoid failing allocations. Link: https://lkml.kernel.org/r/20240312005905.9939-1-duoming@zju.edu.cn Fixes: b2ef9f5a ("mm/hmm/test: add selftest driver for HMM") Signed-off-by:
Duoming Zhou <duoming@zju.edu.cn> Cc: Jérôme Glisse <jglisse@redhat.com> Signed-off-by:
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Johannes Weiner authored
All zswap backends track their pool sizes in pages. Currently they multiply by PAGE_SIZE for zswap, only for zswap to divide again in order to do limit math. Report pages directly. Link: https://lkml.kernel.org/r/20240312153901.3441-2-hannes@cmpxchg.orgSigned-off-by:
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Johannes Weiner authored
Profiling the munmap() of a zswapped memory region shows 60% of the total cycles currently going into updating the zswap_pool_total_size. There are three consumers of this counter: - store, to enforce the globally configured pool limit - meminfo & debugfs, to report the size to the user - shrink, to determine the batch size for each cycle Instead of aggregating everytime an entry enters or exits the zswap pool, aggregate the value from the zpools on-demand: - Stores aggregate the counter anyway upon success. Aggregating to check the limit instead is the same amount of work. - Meminfo & debugfs might benefit somewhat from a pre-aggregated counter, but aren't exactly hotpaths. - Shrinking can aggregate once for every cycle instead of doing it for every freed entry. As the shrinker might work on tens or hundreds of objects per scan cycle, this is a large reduction in aggregations. The paths that benefit dramatically are swapin, swapoff, and unmaps. There could be millions of pages being processed until somebody asks for the pool size again. This eliminates the pool size updates from those paths entirely. Top profile entries for a 24G range munmap(), before: 38.54% zswap-unmap [kernel.kallsyms] [k] zs_zpool_total_size 12.51% zswap-unmap [kernel.kallsyms] [k] zpool_get_total_size 9.10% zswap-unmap [kernel.kallsyms] [k] zswap_update_total_size 2.95% zswap-unmap [kernel.kallsyms] [k] obj_cgroup_uncharge_zswap 2.88% zswap-unmap [kernel.kallsyms] [k] __slab_free 2.86% zswap-unmap [kernel.kallsyms] [k] xas_store and after: 7.70% zswap-unmap [kernel.kallsyms] [k] __slab_free 7.16% zswap-unmap [kernel.kallsyms] [k] obj_cgroup_uncharge_zswap 6.74% zswap-unmap [kernel.kallsyms] [k] xas_store It was also briefly considered to move to a single atomic in zswap that is updated by the backends, since zswap only cares about the sum of all pools anyway. However, zram directly needs per-pool information out of zsmalloc. To keep the backend from having to update two atomics every time, I opted for the lazy aggregation instead for now. Link: https://lkml.kernel.org/r/20240312153901.3441-1-hannes@cmpxchg.orgSigned-off-by: -
Peter Xu authored
There's one small section already, but since we're going to remove pXd_huge(), that comment may start to obsolete. Rewrite that section with more information, hopefully with that the API is crystal clear on what it implies. Link: https://lkml.kernel.org/r/20240318200404.448346-15-peterx@redhat.comSigned-off-by:
Peter Xu <peterx@redhat.com> Reviewed-by:
Jason Gunthorpe <jgg@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bjorn Andersson <andersson@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fabio Estevam <festevam@denx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Konrad Dybcio <konrad.dybcio@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Mark Salter <msalter@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by:
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Peter Xu authored
ARM/ARM64 used to define pmd_thp_or_huge(). Now this macro is completely redundant. Remove it and use pmd_leaf(). Link: https://lkml.kernel.org/r/20240318200404.448346-14-peterx@redhat.comSigned-off-by:
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Peter Xu authored
This API is not used anymore, drop it for the whole tree. Link: https://lkml.kernel.org/r/20240318200404.448346-13-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Now after we're sure all pXd_huge() definitions are the same as pXd_leaf(), reuse it. Luckily, pXd_huge() isn't widely used. Link: https://lkml.kernel.org/r/20240318200404.448346-12-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Huge mapping checks in GUP are slightly redundant and can be simplified. pXd_huge() now is the same as pXd_leaf(). pmd_trans_huge() and pXd_devmap() should both imply pXd_leaf(). Time to merge them into one. Link: https://lkml.kernel.org/r/20240318200404.448346-11-peterx@redhat.comSigned-off-by:
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Peter Xu authored
PowerPC book3s 4K mostly has the same definition on both, except pXd_huge() constantly returns 0 for hash MMUs. As Michael Ellerman pointed out [1], it is safe to check _PAGE_PTE on hash MMUs, as the bit will never be set so it will keep returning false. As a reference, __p[mu]d_mkhuge() will trigger a BUG_ON trying to create such huge mappings for 4K hash MMUs. Meanwhile, the major powerpc hugetlb pgtable walker __find_linux_pte() already used pXd_leaf() to check leaf hugetlb mappings. The goal should be that we will have one API pXd_leaf() to detect all kinds of huge mappings (hugepd is still special in this case, though). AFAICT we need to use the pXd_leaf() impl (rather than pXd_huge()'s) to make sure ie. THPs on hash MMU will also return true. This helps to simplify a follow up patch to drop pXd_huge() treewide. NOTE: *_leaf() definition need to be moved before the inclusion of asm/book3s/64/pgtable-4k.h, which defines pXd_huge() with it. [1] https://lore.kernel.org/r/87v85zo6w7.fsf@mail.lhotse Link: https://lkml.kernel.org/r/20240318200404.448346-10-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Unlike most archs, aarch64 defines pXd_huge() and pXd_leaf() slightly differently. Redefine the pXd_huge() with pXd_leaf(). There used to be two traps for old aarch64 definitions over these APIs that I found when reading the code around, they're: (1) 4797ec2d ("arm64: fix pud_huge() for 2-level pagetables") (2) 23bc8f69 ("arm64: mm: fix p?d_leaf()") Define pXd_huge() with the current pXd_leaf() will make sure (2) isn't a problem (on PROT_NONE checks). To make sure it also works for (1), we move over the __PAGETABLE_PMD_FOLDED check to pud_leaf(), allowing it to constantly returning "false" for 2-level pgtables, which looks even safer to cover both now. Link: https://lkml.kernel.org/r/20240318200404.448346-9-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Most of the archs already define these two APIs the same way. ARM is more complicated in two aspects: - For pXd_huge() it's always checking against !PXD_TABLE_BIT, while for pXd_leaf() it's always checking against PXD_TYPE_SECT. - SECT/TABLE bits are defined differently on 2-level v.s. 3-level ARM pgtables, which makes the whole thing even harder to follow. Luckily, the second complexity should be hidden by the pmd_leaf() implementation against 2-level v.s. 3-level headers. Invoke pmd_leaf() directly for pmd_huge(), to remove the first part of complexity. This prepares to drop pXd_huge() API globally. When at it, drop the obsolete comments - it's outdated. Link: https://lkml.kernel.org/r/20240318200404.448346-8-peterx@redhat.comSigned-off-by: -
Peter Xu authored
It's already confusing that ARM 2-level v.s. 3-level defines SECT bit differently on pmd/puds. Always use a macro which is much clearer. Link: https://lkml.kernel.org/r/20240318200404.448346-7-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Please refer to the previous patch on the reasoning for x86. Now sparc is the only architecture that will allow swap entries to be reported as pXd_huge(). After this patch, all architectures should forbid swap entries in pXd_huge(). [akpm@linux-foundation.org: s/;;/;/, per Muchun] Link: https://lkml.kernel.org/r/20240318200404.448346-6-peterx@redhat.comSigned-off-by:
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Peter Xu authored
This patch partly reverts below commits: 3a194f3f ("mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry") cbef8478 ("mm/hugetlb: pmd_huge() returns true for non-present hugepage") Right now, pXd_huge() definition across kernel is unclear. We have two groups that think differently on swap entries: - x86/sparc: Allow pXd_huge() to accept swap entries - all the rest: Doesn't allow pXd_huge() to accept swap entries This is so confusing. Since the sparc helpers seem to be added in 2016, which is after x86's (2015), so sparc could have followed a trend. x86 proposed such swap handling in 2015 to resolve hugetlb swap entries hit in GUP, but now GUP guards swap entries with !pXd_present() in all layers so we should be safe. We should define this API properly, one way or another, rather than keep them defined differently across archs. Gut feeling tells me that pXd_huge() shouldn't include swap entries, and it turns out that I am not the only one thinking so, the question was raised when the current pmd_huge() for x86 was proposed by Ville Syrjälä: https://lore.kernel.org/all/Y2WQ7I4LXh8iUIRd@intel.com/ I might also be missing something obvious, but why is it even necessary to treat PRESENT==0+PSE==0 as a huge entry? It is also questioned when Jason Gunthorpe reviewed the other patchset on swap entry handlings: https://lore.kernel.org/all/20240221125753.GQ13330@nvidia.com/ Revert its meaning back to original. It shouldn't have any functional change as we should be ready with guards on !pXd_present() explicitly everywhere. Note that I also dropped the "#if CONFIG_PGTABLE_LEVELS > 2", it was there probably because it was breaking things when 3a194f3f was proposed, according to the report here: https://lore.kernel.org/all/Y2LYXItKQyaJTv8j@intel.com/ Now we shouldn't need that. Instead of reverting to _PAGE_PSE raw check, leverage pXd_leaf(). Link: https://lkml.kernel.org/r/20240318200404.448346-5-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Currently there should have no p4d swap entries so it may not matter much, however this may help us to rule out swap entries in pXd_huge() API, which will include p4d_huge(). The p4d_present() checks make it 100% clear that we won't rely on p4d_huge() for swap entries. Link: https://lkml.kernel.org/r/20240318200404.448346-4-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Add a variable to cache p4d in follow_p4d_mask(). It's a good practise to make sure all the following checks will have a consistent view of the entry. Link: https://lkml.kernel.org/r/20240318200404.448346-3-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Swap pud entries do not always return true for pud_huge() for all archs. x86 and sparc (so far) allow it, but all the rest do not accept a swap entry to be reported as pud_huge(). So it's not safe to check swap entries within pud_huge(). Check swap entries before pud_huge(), so it should be always safe. This is the only place in the kernel that (IMHO, wrongly) relies on pud_huge() to return true on pud swap entries. The plan is to cleanup pXd_huge() to only report non-swap mappings for all archs. Link: https://lkml.kernel.org/r/20240318200404.448346-2-peterx@redhat.comSigned-off-by:
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Lucas Stach authored
Patch series "mm/treewide: Remove pXd_huge() API", v2. In previous work [1], we removed the pXd_large() API, which is arch specific. This patchset further removes the hugetlb pXd_huge() API. Hugetlb was never special on creating huge mappings when compared with other huge mappings. Having a standalone API just to detect such pgtable entries is more or less redundant, especially after the pXd_leaf() API set is introduced with/without CONFIG_HUGETLB_PAGE. When looking at this problem, a few issues are also exposed that we don't have a clear definition of the *_huge() variance API. This patchset started by cleaning these issues first, then replace all *_huge() users to use *_leaf(), then drop all *_huge() code. On x86/sparc, swap entries will be reported "true" in pXd_huge(), while for all the rest archs they're reported "false" instead. This part is done in patch 1-5, in which I suspect patch 1 can be seen as a bug fix, but I'll leave that to hmm experts to decide. Besides, there are three archs (arm, arm64, powerpc) that have slightly different definitions between the *_huge() v.s. *_leaf() variances. I tackled them separately so that it'll be easier for arch experts to chim in when necessary. This part is done in patch 6-9. The final patches 10-14 do the rest on the final removal, since *_leaf() will be the ultimate API in the future, and we seem to have quite some confusions on how *_huge() APIs can be defined, provide a rich comment for *_leaf() API set to define them properly to avoid future misuse, and hopefully that'll also help new archs to start support huge mappings and avoid traps (like either swap entries, or PROT_NONE entry checks). [1] https://lore.kernel.org/r/20240305043750.93762-1-peterx@redhat.com This patch (of 14): When the complete PCP is drained a much larger number of pages than the usual batch size might be freed at once, causing large IRQ and preemption latency spikes, as they are all freed while holding the pcp and zone spinlocks. To avoid those latency spikes, limit the number of pages freed in a single bulk operation to common batch limits. Link: https://lkml.kernel.org/r/20240318200404.448346-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20240318200736.2835502-1-l.stach@pengutronix.deSigned-off-by:
Lucas Stach <l.stach@pengutronix.de> Signed-off-by:
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Dev Jain authored
mmap() must not succeed in validate_lower_address_hint(), for if it does, it is a bug in mmap() itself. Reflect this behaviour with ksft_exit_fail_msg(). While at it, do some formatting changes. Link: https://lkml.kernel.org/r/20240314122250.68534-1-dev.jain@arm.comSigned-off-by:
Dev Jain <dev.jain@arm.com> Reviewed-by:
Muhammad Usama Anjum <usama.anjum@collabora.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
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David Hildenbrand authored
We changed faultin_page_range() to no longer consume a VMA, because faultin_page_range() might internally release the mm lock to lookup the VMA again -- required to cleanly handle VM_FAULT_RETRY. But independent of that, __get_user_pages() will always lookup the VMA itself. Now that we let __get_user_pages() just handle VMA checks in a way that is suitable for MADV_POPULATE_(READ|WRITE), the VMA walk in madvise() is just overhead. So let's just call madvise_populate() on the full range instead. There is one change in behavior: madvise_walk_vmas() would skip any VMA holes, and if everything succeeded, it would return -ENOMEM after processing all VMAs. However, for MADV_POPULATE_(READ|WRITE) it's unlikely for the caller to notice any difference: -ENOMEM might either indicate that there were VMA holes or that populating page tables failed because there was not enough memory. So it's unlikely that user space will notice the difference, and that special handling likely only makes sense for some other madvise() actions. Further, we'd already fail with -ENOMEM early in the past if looking up the VMA after dropping the MM lock failed because of concurrent VMA modifications. So let's just keep it simple and avoid the madvise VMA walk, and consistently fail early if we find a VMA hole. Link: https://lkml.kernel.org/r/20240314161300.382526-3-david@redhat.comSigned-off-by:
David Hildenbrand <david@redhat.com> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Signed-off-by:
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Yosry Ahmed authored
9 out of 16 callers perform a NULL check before calling obj_cgroup_put(). Move the NULL check in the function, similar to mem_cgroup_put(). The unlikely() NULL check in current_objcg_update() was left alone to avoid dropping the unlikey() annotation as this a fast path. Link: https://lkml.kernel.org/r/20240316015803.2777252-1-yosryahmed@google.comSigned-off-by:
Roman Gushchin <roman.gushchin@linux.dev> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by:
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