Messages in this thread | | | From | jim.cromie@gmail ... | Date | Fri, 10 Nov 2023 14:00:37 -0700 | Subject | Re: [PATCH v1 07/12] dyndbg: repack struct _ddebug |
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On Fri, Nov 10, 2023 at 7:51 AM Łukasz Bartosik <lb@semihalf.com> wrote: > > sob., 4 lis 2023 o 02:49 <jim.cromie@gmail.com> napisał(a): > > > > On Fri, Nov 3, 2023 at 7:10 AM Łukasz Bartosik <lb@semihalf.com> wrote: > > > > > > From: Jim Cromie <jim.cromie@gmail.com> > > > > > > Move the JUMP_LABEL to the top of the struct, since theyre both > > > align(8) and this closes a pahole (unfortunately trading for padding, > > > but still). > > > > > > Signed-off-by: Jim Cromie <jim.cromie@gmail.com> > > > > let me add, I havent really tested this, nevermind thorough. > > specifically, I didnt look for any offset dependence on the static-key > > inside their container. > > Conversely, maybe theres a free default or something in there. > > > > Any idea how to properly test the relocation of the key ?
I was hoping Jason knew it from memory.
I have booted dd-kitchen-sink, which includes it, and it didnt melt the box.
I just checked `pahole vmlinux` output for the existence of 0-offset keys. Its not conclusive, cuz im only looking at x86.
it does occur, but only for "sub-types".
struct static_key_true { struct static_key key; /* 0 16 */
/* size: 16, cachelines: 1, members: 1 */ /* last cacheline: 16 bytes */ }; struct static_key_false { struct static_key key; /* 0 16 */
/* size: 16, cachelines: 1, members: 1 */ /* last cacheline: 16 bytes */ }; struct static_key_false_deferred { struct static_key_false key; /* 0 16 */ ...}; struct static_key_mod { struct static_key_mod * next; /* 0 8 */ ...}; struct static_key_deferred { struct static_key key; /* 0 16 */
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