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Revision 1.17 / (download) - annotate - [select for diffs], Wed Jul 27 17:05:56 2022 UTC (22 months, 1 week ago) by bluhm
Branch: MAIN
CVS Tags: OPENBSD_7_5_BASE,
OPENBSD_7_5,
OPENBSD_7_4_BASE,
OPENBSD_7_4,
OPENBSD_7_3_BASE,
OPENBSD_7_3,
OPENBSD_7_2_BASE,
OPENBSD_7_2,
HEAD
Changes since 1.16: +3 -3 lines
Diff to previous 1.16 (colored)
srp_finalize() takes two parameter, but only one was documented. OK jmatthew@
Revision 1.16 / (download) - annotate - [select for diffs], Thu Mar 31 17:27:23 2022 UTC (2 years, 2 months ago) by naddy
Branch: MAIN
CVS Tags: OPENBSD_7_1_BASE,
OPENBSD_7_1
Changes since 1.15: +3 -3 lines
Diff to previous 1.15 (colored)
man pages: add missing commas between subordinate and main clauses jmc@ dislikes a comma before "then" in a conditional, so leave those untouched. ok jmc@
Revision 1.15 / (download) - annotate - [select for diffs], Wed Jan 18 13:18:07 2017 UTC (7 years, 4 months ago) by dlg
Branch: MAIN
CVS Tags: OPENBSD_7_0_BASE,
OPENBSD_7_0,
OPENBSD_6_9_BASE,
OPENBSD_6_9,
OPENBSD_6_8_BASE,
OPENBSD_6_8,
OPENBSD_6_7_BASE,
OPENBSD_6_7,
OPENBSD_6_6_BASE,
OPENBSD_6_6,
OPENBSD_6_5_BASE,
OPENBSD_6_5,
OPENBSD_6_4_BASE,
OPENBSD_6_4,
OPENBSD_6_3_BASE,
OPENBSD_6_3,
OPENBSD_6_2_BASE,
OPENBSD_6_2,
OPENBSD_6_1_BASE,
OPENBSD_6_1
Changes since 1.14: +3 -3 lines
Diff to previous 1.14 (colored)
didnt rename enough things after copy/paste
Revision 1.14 / (download) - annotate - [select for diffs], Wed Jul 27 12:55:41 2016 UTC (7 years, 10 months ago) by jca
Branch: MAIN
Changes since 1.13: +3 -2 lines
Diff to previous 1.13 (colored)
Missing word ("no").
Revision 1.13 / (download) - annotate - [select for diffs], Tue Jun 7 14:37:46 2016 UTC (8 years ago) by jmc
Branch: MAIN
CVS Tags: OPENBSD_6_0_BASE,
OPENBSD_6_0
Changes since 1.12: +4 -4 lines
Diff to previous 1.12 (colored)
tweak previous;
Revision 1.12 / (download) - annotate - [select for diffs], Tue Jun 7 11:59:31 2016 UTC (8 years ago) by dlg
Branch: MAIN
Changes since 1.11: +41 -1 lines
Diff to previous 1.11 (colored)
document the new bits in the srp api
Revision 1.11 / (download) - annotate - [select for diffs], Wed May 18 03:58:13 2016 UTC (8 years ago) by dlg
Branch: MAIN
Changes since 1.10: +6 -6 lines
Diff to previous 1.10 (colored)
rename srp_finalize to srp_gc_finalize
Revision 1.10 / (download) - annotate - [select for diffs], Wed May 18 03:46:03 2016 UTC (8 years ago) by dlg
Branch: MAIN
Changes since 1.9: +12 -49 lines
Diff to previous 1.9 (colored)
rework the srp api so it takes an srp_ref struct that the caller provides. the srp_ref struct is used to track the location of the callers hazard pointer so later calls to srp_follow and srp_enter already know what to clear. this in turn means most of the caveats around using srps go away. specifically, you can now: - switch cpus while holding an srp ref - ie, you can sleep while holding an srp ref - you can take and release srp refs in any order the original intent was to simplify use of the api when dealing with complicated data structures. the caller now no longer has to track the location of the srp a value was fetched from, the srp_ref effectively does that for you. srp lists have been refactored to use srp_refs instead of srpl_iter structs. this is in preparation of using srps inside the ART code. ART is a complicated data structure, and lookups require overlapping holds of srp references. ok mpi@ jmatthew@
Revision 1.9 / (download) - annotate - [select for diffs], Fri Feb 12 12:52:28 2016 UTC (8 years, 3 months ago) by dlg
Branch: MAIN
CVS Tags: OPENBSD_5_9_BASE,
OPENBSD_5_9
Changes since 1.8: +1 -1 lines
Diff to previous 1.8 (colored)
i think this is a grammar fix
Revision 1.8 / (download) - annotate - [select for diffs], Fri Feb 12 12:48:44 2016 UTC (8 years, 3 months ago) by dlg
Branch: MAIN
Changes since 1.7: +3 -3 lines
Diff to previous 1.7 (colored)
srp_update_get_locked doesnt exist, i meant srp_get_locked
Revision 1.7 / (download) - annotate - [select for diffs], Fri Feb 12 12:47:04 2016 UTC (8 years, 3 months ago) by dlg
Branch: MAIN
Changes since 1.6: +14 -4 lines
Diff to previous 1.6 (colored)
tweak the description and make it obvious updates can sleep. based on discussion with haesbart and jmatthew
Revision 1.6 / (download) - annotate - [select for diffs], Fri Oct 2 09:26:16 2015 UTC (8 years, 8 months ago) by sobrado
Branch: MAIN
Changes since 1.5: +4 -4 lines
Diff to previous 1.5 (colored)
typos.
Revision 1.5 / (download) - annotate - [select for diffs], Mon Sep 14 15:14:55 2015 UTC (8 years, 8 months ago) by schwarze
Branch: MAIN
Changes since 1.4: +13 -13 lines
Diff to previous 1.4 (colored)
Remove useless quoting from .Fo and .Fn function names, to prevent development of a cargo cult in case people look at existing files for examples. This achieves a consistent .Fo and .Fn quoting style across the whole tree.
Revision 1.4 / (download) - annotate - [select for diffs], Tue Sep 1 03:47:58 2015 UTC (8 years, 9 months ago) by dlg
Branch: MAIN
Changes since 1.3: +53 -7 lines
Diff to previous 1.3 (colored)
mattieu baptiste reported a problem with bpf+srps where the per cpu hazard pointers were becoming corrupt and therefore panics. the problem turned out to be that bridge_input calls if_input on behalf of a hardware interface which then calls bpf_mtap at splsoftnet, while the actual hardware nic calls if_input and bpf_mtap at splnet. the hardware interrupts ran in the middle of the bpf calls bridge runs at softnet. this means the same srps are being entered and left on the same cpu at different ipls, which led to races because of the order of operations on the per cpu hazard pointers. after a lot of experimentation, jmatthew@ figured out how to deal with this problem without introducing per cpu critical sections (ie, splhigh) calls in srp_enter and srp_leave, and without introducing atomic operations. the solution is to iterate forward through the array of hazard pointers in srp_enter, and backward in srp_leave to clear. if you guarantee that you leave srps in the reverse order to entering them, then you can use the same set of SRPs at different IPLs on the same CPU. the ordering requirement is a problem if we want to build linked data structures out of srps because you need to hold a ref to the current element containing the next srp to use it, before giving up the current ref. we're adding srp_follow() to support taking the next ref and giving up the current one while preserving the structure of the hazard pointer list. srp_follow() does this by reusing the hazard pointer for the current reference for the next ref. both mattieu baptiste and jmatthew@ have been hitting this pretty hard with a tweaked version of srp+bpf that uses srp_follow instead of interleaved srp_enter/srp_leave sequences. neither can reproduce the panics anymore. thanks to mattieu for the report and tests ok jmatthew@
Revision 1.3 / (download) - annotate - [select for diffs], Fri Aug 14 05:18:50 2015 UTC (8 years, 9 months ago) by dlg
Branch: MAIN
Changes since 1.2: +1 -1 lines
Diff to previous 1.2 (colored)
imply you cant sleep while holding a ref via srp
Revision 1.2 / (download) - annotate - [select for diffs], Thu Jul 2 01:38:35 2015 UTC (8 years, 11 months ago) by dlg
Branch: MAIN
CVS Tags: OPENBSD_5_8_BASE,
OPENBSD_5_8
Changes since 1.1: +7 -2 lines
Diff to previous 1.1 (colored)
mikeb@ suggested making it clear that srp_enter and srp_leave pairs have to be called in the same context.
Revision 1.1 / (download) - annotate - [select for diffs], Thu Jul 2 01:33:59 2015 UTC (8 years, 11 months ago) by dlg
Branch: MAIN
introduce srp, which according to the manpage i wrote is short for "shared reference pointers". srp allows concurrent access to a data structure by multiple cpus while avoiding interlocking cpu opcodes. it manages its own reference counts and the garbage collection of those data structure to avoid use after frees. internally srp is a twisted version of hazard pointers, which are a relative of RCU. jmatthew wrote the bulk of a hazard pointer implementation and changed bpf to use it to allow mpsafe access to bpfilters. however, at s2k15 we were trying to apply it to other data structures but the memory overhead of every hazard pointer would have blown out significantly in several uses cases. a bulk of our time at s2k15 was spent reworking hazard pointers into srp. this diff adds the srp api and adds the necessary metadata to struct cpuinfo on our MP architectures. srp on uniprocessor platforms has alternate code that is optimised because it knows there'll be no concurrent access to data by multiple cpus. srp is made available to the system via param.h, so it should be available everywhere in the kernel. the docs likely need improvement cos im too close to the implementation. ok mpi@