This patchset implements several improvements: 1. Gracefully handles module unloading while there are used allocations allocated from that module; 2. Provides an option to reduce memory overhead from storing page allocation references by indexing allocation tags; 3. Provides an option to store page allocation tag references in the page flags, removing dependency on page extensions and eliminating the memory overhead from storing page allocation references (~0.2% of total system memory). 4. Improves page allocation performance when CONFIG_MEM_ALLOC_PROFILING is enabled by eliminating page extension lookup. Page allocation performance overhead is reduced from 14% to 5.5%. Patch #1 copies module tags into virtually contiguous memory which serves two purposes: - Lets us deal with the situation when module is unloaded while there are still live allocations from that module. Since we are using a copy version of the tags we can safely unload the module. Space and gaps in this contiguous memory are managed using a maple tree. - Enables simple indexing of the tags in the later patches. Preallocated virtually contiguous memory size can be configured using max_module_alloc_tags kernel parameter. Patch #2 is a code cleanup to simplify later changes. Patch #3 abstracts page allocation tag reference to simplify later changes. Patch #4 lets us control page allocation tag reference sizes and introduces tag indexing. Patch #5 adds a config to store page allocation tag references inside page flags if they fit. Patchset applies to mm-unstable. Suren Baghdasaryan (5): alloc_tag: load module tags into separate continuous memory alloc_tag: eliminate alloc_tag_ref_set alloc_tag: introduce pgalloc_tag_ref to abstract page tag references alloc_tag: make page allocation tag reference size configurable alloc_tag: config to store page allocation tag refs in page flags .../admin-guide/kernel-parameters.txt | 4 + include/asm-generic/codetag.lds.h | 19 ++ include/linux/alloc_tag.h | 46 ++- include/linux/codetag.h | 38 ++- include/linux/mmzone.h | 3 + include/linux/page-flags-layout.h | 10 +- include/linux/pgalloc_tag.h | 257 ++++++++++++--- kernel/module/main.c | 67 ++-- lib/Kconfig.debug | 36 ++- lib/alloc_tag.c | 300 ++++++++++++++++-- lib/codetag.c | 105 +++++- mm/mm_init.c | 1 + mm/page_ext.c | 2 +- scripts/module.lds.S | 5 +- 14 files changed, 759 insertions(+), 134 deletions(-) base-commit: 651c8c1d735983040bec4f71d0e2e690f3c0fc2d -- 2.46.0.184.g6999bdac58-goog
