Memory allocation, v3 and final: Overview: Low overhead [1] per-callsite memory allocation profiling. Not just for debug kernels, overhead low enough to be deployed in production. We're aiming to get this in the next merge window, for 6.9. The feedback we've gotten has been that even out of tree this patchset has already been useful, and there's a significant amount of other work gated on the code tagging functionality included in this patchset [2]. Example output: root@moria-kvm:~# sort -h /proc/allocinfo|tail 3.11MiB 2850 fs/ext4/super.c:1408 module:ext4 func:ext4_alloc_inode 3.52MiB 225 kernel/fork.c:356 module:fork func:alloc_thread_stack_node 3.75MiB 960 mm/page_ext.c:270 module:page_ext func:alloc_page_ext 4.00MiB 2 mm/khugepaged.c:893 module:khugepaged func:hpage_collapse_alloc_folio 10.5MiB 168 block/blk-mq.c:3421 module:blk_mq func:blk_mq_alloc_rqs 14.0MiB 3594 include/linux/gfp.h:295 module:filemap func:folio_alloc_noprof 26.8MiB 6856 include/linux/gfp.h:295 module:memory func:folio_alloc_noprof 64.5MiB 98315 fs/xfs/xfs_rmap_item.c:147 module:xfs func:xfs_rui_init 98.7MiB 25264 include/linux/gfp.h:295 module:readahead func:folio_alloc_noprof 125MiB 7357 mm/slub.c:2201 module:slub func:alloc_slab_page Since v2: - tglx noticed a circular header dependency between sched.h and percpu.h; a bunch of header cleanups were merged into 6.8 to ameliorate this [3]. - a number of improvements, moving alloc_hooks() annotations to the correct place for better tracking (mempool), and bugfixes. - looked at alternate hooking methods. There were suggestions on alternate methods (compiler attribute, trampolines), but they wouldn't have made the patchset any cleaner (we still need to have different function versions for accounting vs. no accounting to control at which point in a call chain the accounting happens), and they would have added a dependency on toolchain support. 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 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%) 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. [2]: Improved fault injection is the big one; the alloc_hooks() macro this patchset introduces is also used for per-callsite fault injection points in the dynamic fault injection patchset, which means we can easily do fault injection on a per module or per file basis; this makes it much easier to integrate memory fault injection into existing tests. Vlastimil recently raised concerns about exposing GFP_NOWAIT as a PF_MEMALLOC_* flag, as this might introduce GFP_NOWAIT to allocation paths that have never had their failure paths tested - this is something we need to address. [3]: The circular dependency looks to be unavoidable; the issue is that alloc_tag_save() -> current -> get_current() requires percpu.h, and percpu.h requires sched.h because of course it does. But this doesn't actually cause build errors because we're only using macros, so the main concern is just not leaving a difficult-to-disentangle minefield for later. So, sched.h is now pretty close to being a types only header that imports types and declares types - this is the header cleanups that were merged for 6.8. Kent Overstreet (11): lib/string_helpers: Add flags param to string_get_size() scripts/kallysms: Always include __start and __stop symbols fs: Convert alloc_inode_sb() to a macro mm/slub: Mark slab_free_freelist_hook() __always_inline mempool: Hook up to memory allocation profiling xfs: Memory allocation profiling fixups mm: percpu: Introduce pcpuobj_ext mm: percpu: Add codetag reference into pcpuobj_ext mm: vmalloc: Enable memory allocation profiling rhashtable: Plumb through alloc tag MAINTAINERS: Add entries for code tagging and memory allocation profiling Suren Baghdasaryan (24): mm: enumerate all gfp flags mm: introduce slabobj_ext to support slab object extensions mm: introduce __GFP_NO_OBJ_EXT flag to selectively prevent slabobj_ext creation mm/slab: introduce SLAB_NO_OBJ_EXT to avoid obj_ext creation mm: prevent slabobj_ext allocations for slabobj_ext and kmem_cache objects slab: objext: introduce objext_flags as extension to page_memcg_data_flags lib: code tagging framework lib: code tagging module support lib: prevent module unloading if memory is not freed lib: add allocation tagging support for memory allocation profiling lib: introduce support for page allocation tagging mm: percpu: increase PERCPU_MODULE_RESERVE to accommodate allocation tags change alloc_pages name in dma_map_ops to avoid name conflicts mm: enable page allocation tagging mm: create new codetag references during page splitting mm/page_ext: enable early_page_ext when CONFIG_MEM_ALLOC_PROFILING_DEBUG=y lib: add codetag reference into slabobj_ext mm/slab: add allocation accounting into slab allocation and free paths mm/slab: enable slab allocation tagging for kmalloc and friends mm: percpu: enable per-cpu allocation tagging lib: add memory allocations report in show_mem() codetag: debug: skip objext checking when it's for objext itself codetag: debug: mark codetags for reserved pages as empty codetag: debug: introduce OBJEXTS_ALLOC_FAIL to mark failed slab_ext allocations Documentation/admin-guide/sysctl/vm.rst | 16 ++ Documentation/filesystems/proc.rst | 28 ++ MAINTAINERS | 16 ++ arch/alpha/kernel/pci_iommu.c | 2 +- arch/mips/jazz/jazzdma.c | 2 +- arch/powerpc/kernel/dma-iommu.c | 2 +- arch/powerpc/mm/book3s64/radix_pgtable.c | 2 +- arch/powerpc/platforms/ps3/system-bus.c | 4 +- arch/powerpc/platforms/pseries/vio.c | 2 +- arch/x86/kernel/amd_gart_64.c | 2 +- drivers/block/virtio_blk.c | 4 +- drivers/gpu/drm/gud/gud_drv.c | 2 +- drivers/iommu/dma-iommu.c | 2 +- drivers/mmc/core/block.c | 4 +- drivers/mtd/spi-nor/debugfs.c | 6 +- .../ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 4 +- drivers/parisc/ccio-dma.c | 2 +- drivers/parisc/sba_iommu.c | 2 +- drivers/scsi/sd.c | 8 +- drivers/staging/media/atomisp/pci/hmm/hmm.c | 2 +- drivers/xen/grant-dma-ops.c | 2 +- drivers/xen/swiotlb-xen.c | 2 +- fs/xfs/kmem.c | 4 +- fs/xfs/kmem.h | 10 +- include/asm-generic/codetag.lds.h | 14 + include/asm-generic/vmlinux.lds.h | 3 + include/linux/alloc_tag.h | 188 +++++++++++++ include/linux/codetag.h | 83 ++++++ include/linux/dma-map-ops.h | 2 +- include/linux/fortify-string.h | 5 +- include/linux/fs.h | 6 +- include/linux/gfp.h | 126 +++++---- include/linux/gfp_types.h | 101 +++++-- include/linux/memcontrol.h | 56 +++- include/linux/mempool.h | 73 +++-- include/linux/mm.h | 8 + include/linux/mm_types.h | 4 +- include/linux/page_ext.h | 1 - include/linux/pagemap.h | 9 +- include/linux/percpu.h | 27 +- include/linux/pgalloc_tag.h | 105 +++++++ include/linux/rhashtable-types.h | 11 +- include/linux/sched.h | 24 ++ include/linux/slab.h | 184 +++++++------ include/linux/string.h | 4 +- include/linux/string_helpers.h | 11 +- include/linux/vmalloc.h | 60 +++- init/Kconfig | 4 + kernel/dma/mapping.c | 4 +- kernel/kallsyms_selftest.c | 2 +- kernel/module/main.c | 25 +- lib/Kconfig.debug | 31 +++ lib/Makefile | 3 + lib/alloc_tag.c | 213 +++++++++++++++ lib/codetag.c | 258 ++++++++++++++++++ lib/rhashtable.c | 52 +++- lib/string_helpers.c | 22 +- lib/test-string_helpers.c | 4 +- mm/compaction.c | 7 +- mm/filemap.c | 6 +- mm/huge_memory.c | 2 + mm/hugetlb.c | 8 +- mm/kfence/core.c | 14 +- mm/kfence/kfence.h | 4 +- mm/memcontrol.c | 56 +--- mm/mempolicy.c | 52 ++-- mm/mempool.c | 36 +-- mm/mm_init.c | 10 + mm/page_alloc.c | 66 +++-- mm/page_ext.c | 13 + mm/page_owner.c | 2 +- mm/percpu-internal.h | 26 +- mm/percpu.c | 120 ++++---- mm/show_mem.c | 15 + mm/slab.h | 176 ++++++++++-- mm/slab_common.c | 65 ++++- mm/slub.c | 138 ++++++---- mm/util.c | 44 +-- mm/vmalloc.c | 88 +++--- scripts/kallsyms.c | 13 + scripts/module.lds.S | 7 + 81 files changed, 2126 insertions(+), 695 deletions(-) create mode 100644 include/asm-generic/codetag.lds.h create mode 100644 include/linux/alloc_tag.h create mode 100644 include/linux/codetag.h create mode 100644 include/linux/pgalloc_tag.h create mode 100644 lib/alloc_tag.c create mode 100644 lib/codetag.c -- 2.43.0.687.g38aa6559b0-goog