From: Sergey Ostanevich via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Sergey Kaplun <skaplun@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH luajit 1/2] Add support for full-range 64 bit lightuserdata. Date: Tue, 10 Aug 2021 19:46:24 +0300 [thread overview] Message-ID: <2D0425B2-B689-43F1-8D1F-1A676E86718B@tarantool.org> (raw) In-Reply-To: <YQgGcfW7bJ4j9Iqk@root> [-- Attachment #1: Type: text/plain, Size: 2566 bytes --] >>> all internal usage of lightuserdata (for hooks, >>> profilers, built-in package, IR and so on) is changed to special values >>> on Lua Stack. >> >> Can you add at least _some_ test to verify memprof is fine? > > Memprof avoids such extroversions. Do you mean the test for `jit.p`? > I can see memeprof is out of the business, sure I meant any our new functionality - such as stats on gc - that can be hit by this in some way. > The new commit message is the following: > > =================================================================== > Add support for full-range 64 bit lightuserdata. > > (cherry picked from commit e9af1abec542e6f9851ff2368e7f196b6382a44c) > > LuaJIT uses special NaN-tagging technique to store internal type on > the Lua stack. In case of LJ_GC64 the first 13 bits are set in special > NaN type (0xfff8...). The next 4 bits are used for an internal LuaJIT > type of object on stack. The next 47 bits are used for storing this > object's content. For userdata, it is its address. For arm64 a pointer > can have more than 47 significant bits [1]. In this case the error BADLU > error is raised. > > For the support of full 64-bit range lightuserdata pointers two new > fields in GCState are added: > > `lightudseg` - vector of segments of lightuserdata. Each element keeps > 32-bit value. 25 MSB equal to MSB of lightuserdata 64-bit address, the > rest are filled with zeros. The lentgh of the vector is power of 2. > > `lightudnum` - the length - 1 of aforementioned vector (up to 255). > > When lightuserdata is pushed on the stack, if its segment is not stored > in vector new value is appended to of this vector. The maximum amount of > segments is 256. BADLU error is raised in case when user tried to add > userdata with the new 257-th segment, so the whole VA-space isn't > covered by this patch. > > Also, in this patch all internal usage of lightuserdata (for hooks, > profilers, built-in package, IR and so on) is changed to special values > on Lua Stack. > > Also, conversion of TValue to FFI C type with store is no longer > compiled for lightuserdata. > > [1]: https://www.kernel.org/doc/html/latest/arm64/memory.html <https://www.kernel.org/doc/html/latest/arm64/memory.html> > > Sergey Kaplun: > * added the description and the test for the problem > > Resolves tarantool/tarantool#2712 > Needed for tarantool/tarantool#6154 > =================================================================== > > Branch is force-pushed. LGTM. Sergos [-- Attachment #2: Type: text/html, Size: 34347 bytes --]
next prev parent reply other threads:[~2021-08-10 16:46 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-06 17:40 [Tarantool-patches] [PATCH luajit 0/2] arm64: fix 48-bit addresses issues Sergey Kaplun via Tarantool-patches 2021-07-06 17:40 ` [Tarantool-patches] [PATCH luajit 1/2] Add support for full-range 64 bit lightuserdata Sergey Kaplun via Tarantool-patches 2021-07-27 13:59 ` Igor Munkin via Tarantool-patches 2021-07-28 12:29 ` Sergey Kaplun via Tarantool-patches 2021-08-01 10:36 ` Igor Munkin via Tarantool-patches 2021-08-02 14:56 ` Sergey Kaplun via Tarantool-patches 2021-08-01 16:25 ` Sergey Ostanevich via Tarantool-patches 2021-08-02 14:51 ` Sergey Kaplun via Tarantool-patches 2021-08-02 15:42 ` Igor Munkin via Tarantool-patches 2021-08-10 16:46 ` Sergey Ostanevich via Tarantool-patches [this message] 2021-08-11 5:54 ` Vitaliia Ioffe via Tarantool-patches 2021-07-06 17:40 ` [Tarantool-patches] [PATCH luajit 2/2] Linux/ARM64: Make mremap() non-moving due to VA space woes Sergey Kaplun via Tarantool-patches 2021-07-27 15:23 ` Igor Munkin via Tarantool-patches 2021-07-28 12:29 ` Sergey Kaplun via Tarantool-patches 2021-08-01 10:36 ` Igor Munkin via Tarantool-patches 2021-08-01 16:59 ` Sergey Ostanevich via Tarantool-patches 2021-08-02 15:08 ` Sergey Kaplun via Tarantool-patches 2021-08-02 15:55 ` Sergey Ostanevich via Tarantool-patches 2021-08-02 15:11 ` Sergey Kaplun via Tarantool-patches 2021-08-11 7:21 ` [Tarantool-patches] [PATCH luajit 0/2] arm64: fix 48-bit addresses issues Igor Munkin via Tarantool-patches
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