Date: Sun, 18 Feb 2018 18:46:56 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r329524 - head/sys/compat/linuxkpi/common/include/asm Message-ID: <201802181846.w1IIkush016425@repo.freebsd.org>
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Author: hselasky Date: Sun Feb 18 18:46:56 2018 New Revision: 329524 URL: https://svnweb.freebsd.org/changeset/base/329524 Log: Optimise xchg() to use atomic_swap_32() and atomic_swap_64(). Suggested by: kib@ MFC after: 1 week Sponsored by: Mellanox Technologies Modified: head/sys/compat/linuxkpi/common/include/asm/atomic.h Modified: head/sys/compat/linuxkpi/common/include/asm/atomic.h ============================================================================== --- head/sys/compat/linuxkpi/common/include/asm/atomic.h Sun Feb 18 17:37:23 2018 (r329523) +++ head/sys/compat/linuxkpi/common/include/asm/atomic.h Sun Feb 18 18:46:56 2018 (r329524) @@ -205,31 +205,31 @@ atomic_cmpxchg(atomic_t *v, int old, int new) u16 u16[0]; \ u32 u32[0]; \ u64 u64[0]; \ - } __ret = { .val = READ_ONCE(*ptr) }, __new = { .val = (new) }; \ + } __ret, __new = { .val = (new) }; \ \ CTASSERT(sizeof(__ret.val) == 1 || sizeof(__ret.val) == 2 || \ sizeof(__ret.val) == 4 || sizeof(__ret.val) == 8); \ \ switch (sizeof(__ret.val)) { \ case 1: \ + __ret.val = READ_ONCE(*ptr); \ while (!atomic_fcmpset_8((volatile u8 *)(ptr), \ __ret.u8, __new.u8[0])) \ ; \ break; \ case 2: \ + __ret.val = READ_ONCE(*ptr); \ while (!atomic_fcmpset_16((volatile u16 *)(ptr), \ __ret.u16, __new.u16[0])) \ ; \ break; \ case 4: \ - while (!atomic_fcmpset_32((volatile u32 *)(ptr), \ - __ret.u32, __new.u32[0])) \ - ; \ + __ret.u32[0] = atomic_swap_32((volatile u32 *)(ptr), \ + __new.u32[0]); \ break; \ case 8: \ - while (!atomic_fcmpset_64((volatile u64 *)(ptr), \ - __ret.u64, __new.u64[0])) \ - ; \ + __ret.u64[0] = atomic_swap_64((volatile u64 *)(ptr), \ + __new.u64[0]); \ break; \ } \ __ret.val; \
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