On Tue, Feb 27, 2024 at 5:35 AM Vlastimil Babka <vbabka@xxxxxxx> wrote: > > On 2/21/24 20:40, Suren Baghdasaryan wrote: > > 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 > > ... > > > > Since v3: > > - Dropped patch changing string_get_size() [2] as not needed > > - Dropped patch modifying xfs allocators [3] as non needed, > > per Dave Chinner > > - Added Reviewed-by, per Kees Cook > > - Moved prepare_slab_obj_exts_hook() and alloc_slab_obj_exts() where they > > are used, per Vlastimil Babka > > - Fixed SLAB_NO_OBJ_EXT definition to use unused bit, per Vlastimil Babka > > - Refactored patch [4] into other patches, per Vlastimil Babka > > - Replaced snprintf() with seq_buf_printf(), per Kees Cook > > - Changed output to report bytes, per Andrew Morton and Pasha Tatashin > > - Changed output to report [module] only for loadable modules, > > per Vlastimil Babka > > - Moved mem_alloc_profiling_enabled() check earlier, per Vlastimil Babka > > - Changed the code to handle page splitting to be more understandable, > > per Vlastimil Babka > > - Moved alloc_tagging_slab_free_hook(), mark_objexts_empty(), > > mark_failed_objexts_alloc() and handle_failed_objexts_alloc(), > > per Vlastimil Babka > > - Fixed loss of __alloc_size(1, 2) in kvmalloc functions, > > per Vlastimil Babka > > - Refactored the code in show_mem() to avoid memory allocations, > > per Michal Hocko > > - Changed to trylock in show_mem() to avoid blocking in atomic context, > > per Tetsuo Handa > > - Added mm mailing list into MAINTAINERS, per Kees Cook > > - Added base commit SHA, per Andy Shevchenko > > - Added a patch with documentation, per Jani Nikula > > - Fixed 0day bugs > > - Added benchmark results [5], per Steven Rostedt > > - Rebased over Linux 6.8-rc5 > > > > Items not yet addressed: > > - An early_boot option to prevent pageext overhead. We are looking into > > ways for using the same sysctr instead of adding additional early boot > > parameter. > > I have reviewed the parts that integrate the tracking with page and slab > allocators, and besides some details to improve it seems ok to me. The > early boot option seems coming so that might eventually be suitable for > build-time enablement in a distro kernel. Thanks for reviewing Vlastimil! > > The macros (and their potential spread to upper layers to keep the > information useful enough) are of course ugly, but guess it can't be > currently helped and I'm unable to decide whether it's worth it or not. > That's up to those providing their success stories I guess. If there's > at least a path ahead to replace that part with compiler support in the > future, great. So I'm not against merging this. BTW, do we know Linus's > opinion on the macros approach? We haven't run it by Linus specifically but hopefully we will see a comment from him on the mailing list at some point. > > -- > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@xxxxxxxxxxx. >
