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    SubjectRe: [PATCH v3 6/6] x86: bug.h: use asm_inline in _BUG_FLAGS definitions

    * Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:

    > This helps preventing a BUG* or WARN* in some static inline from
    > preventing that (or one of its callers) being inlined, so should allow
    > gcc to make better informed inlining decisions.
    >
    > For example, with gcc 9.2, tcp_fastopen_no_cookie() vanishes from
    > net/ipv4/tcp_fastopen.o. It does not itself have any BUG or WARN, but
    > it calls dst_metric() which has a WARN_ON_ONCE - and despite that
    > WARN_ON_ONCE vanishing since the condition is compile-time false,
    > dst_metric() is apparently sufficiently "large" that when it gets
    > inlined into tcp_fastopen_no_cookie(), the latter becomes too large
    > for inlining.
    >
    > Overall, if one asks size(1), .text decreases a little and .data
    > increases by about the same amount (x86-64 defconfig)
    >
    > $ size vmlinux.{before,after}
    > text data bss dec hex filename
    > 19709726 5202600 1630280 26542606 195020e vmlinux.before
    > 19709330 5203068 1630280 26542678 1950256 vmlinux.after
    >
    > while bloat-o-meter says
    >
    > add/remove: 10/28 grow/shrink: 103/51 up/down: 3669/-2854 (815)
    > ...
    > Total: Before=14783683, After=14784498, chg +0.01%
    >
    > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

    Acked-by: Ingo Molnar <mingo@kernel.org>

    Thanks,

    Ingo

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