| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 19 Jan 2024 16:50:53 +0800 From: Shijie Huang <shijie@...eremail.onmicrosoft.com> To: Mike Rapoport <rppt@...nel.org> Cc: Yury Norov <yury.norov@...il.com>, Huang Shijie <shijie@...amperecomputing.com>, gregkh@...uxfoundation.org, patches@...erecomputing.com, rafael@...nel.org, paul.walmsley@...ive.com, palmer@...belt.com, aou@...s.berkeley.edu, kuba@...nel.org, vschneid@...hat.com, mingo@...nel.org, akpm@...ux-foundation.org, vbabka@...e.cz, tglx@...utronix.de, jpoimboe@...nel.org, ndesaulniers@...gle.com, mikelley@...rosoft.com, mhiramat@...nel.org, arnd@...db.de, linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, catalin.marinas@....com, will@...nel.org, mark.rutland@....com, mpe@...erman.id.au, linuxppc-dev@...ts.ozlabs.org, chenhuacai@...nel.org, jiaxun.yang@...goat.com, linux-mips@...r.kernel.org, cl@...amperecomputing.com Subject: Re: [PATCH] NUMA: Early use of cpu_to_node() returns 0 instead of the correct node id 在 2024/1/19 16:42, Mike Rapoport 写道: > On Fri, Jan 19, 2024 at 02:46:16PM +0800, Shijie Huang wrote: >> 在 2024/1/19 12:42, Yury Norov 写道: >>> This adds another level of indirection, I think. Currently cpu_to_node >>> is a simple inliner. After the patch it would be a real function with >>> all the associate overhead. Can you share a bloat-o-meter output here? >> #./scripts/bloat-o-meter vmlinux vmlinux.new >> add/remove: 6/1 grow/shrink: 61/51 up/down: 1168/-588 (580) >> Function old new delta >> numa_update_cpu 148 244 +96 >> >> ...................................................................................................................................(to many to skip) >> >> Total: Before=32990130, After=32990710, chg +0.00% > > It's not only about text size, the indirect call also hurts performance > The cpu_to_node() is called at very low frequency, most of the times is in the kernel booting time. >>> Regardless, I don't think that the approach is correct. As per your >>> description, some initialization functions erroneously call >>> cpu_to_node() instead of early_cpu_to_node() which exists specifically >>> for that case. >>> >>> If the above correct, it's clearly a caller problem, and the fix is to >>> simply switch all those callers to use early version. >> It is easy to change to early_cpu_to_node() for sched_init(), >> init_sched_fair_class() >> >> and workqueue_init_early(). These three places call the cpu_to_node() in the >> __init function. >> >> >> But it is a little hard to change the early_trace_init(), since it calls >> cpu_to_node in the deep >> >> function stack: >> >> early_trace_init() --> ring_buffer_alloc() -->rb_allocate_cpu_buffer() >> >> >> For early_trace_init(), we need to change more code. >> >> >> Anyway, If we think it is not a good idea to change the common code, I am >> oaky too. > > Is there a fundamental reason to have early_cpu_to_node() at all? The early_cpu_to_node does not work on some ARCHs (which support the NUMA), such as SPARC, MIPS and S390. Thanks Huang Shijie > It seems that all the mappings are known by the end of setup_arch() and the > initialization of numa_node can be moved earlier. > >>> I would also initialize the numa_node with NUMA_NO_NODE at declaration, >>> so that if someone calls cpu_to_node() before the variable is properly >>> initialized at runtime, he'll get NO_NODE, which is obviously an error. >> Even we set the numa_node with NUMA_NO_NODE, it does not always produce >> error. >> >> Please see the alloc_pages_node(). >> >> >> Thanks >> >> Huang Shijie >>
Powered by blists - more mailing lists