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| author | Uros Bizjak <ubizjak@gmail.com> | 2024-11-20 16:06:22 +0100 |
|---|---|---|
| committer | Carlos Maiolino <cem@kernel.org> | 2024-11-28 12:42:10 +0100 |
| commit | 214093534f3c046bf5acc9affbf4e6bd9af4538b (patch) | |
| tree | 29f33ee46047abd178ea69803365a8b8645b5e9a /fs/xfs | |
| parent | a8581099604dfa609a34a3fac8ef5af0d300d2c1 (diff) | |
| download | linux-stable-214093534f3c046bf5acc9affbf4e6bd9af4538b.tar.gz linux-stable-214093534f3c046bf5acc9affbf4e6bd9af4538b.tar.bz2 linux-stable-214093534f3c046bf5acc9affbf4e6bd9af4538b.zip | |
xfs: Use xchg() in xlog_cil_insert_pcp_aggregate()
try_cmpxchg() loop with constant "new" value can be substituted
with just xchg() to atomically get and clear the location.
The code on x86_64 improves from:
1e7f: 48 89 4c 24 10 mov %rcx,0x10(%rsp)
1e84: 48 03 14 c5 00 00 00 add 0x0(,%rax,8),%rdx
1e8b: 00
1e88: R_X86_64_32S __per_cpu_offset
1e8c: 8b 02 mov (%rdx),%eax
1e8e: 41 89 c5 mov %eax,%r13d
1e91: 31 c9 xor %ecx,%ecx
1e93: f0 0f b1 0a lock cmpxchg %ecx,(%rdx)
1e97: 75 f5 jne 1e8e <xlog_cil_commit+0x84e>
1e99: 48 8b 4c 24 10 mov 0x10(%rsp),%rcx
1e9e: 45 01 e9 add %r13d,%r9d
to just:
1e7f: 48 03 14 cd 00 00 00 add 0x0(,%rcx,8),%rdx
1e86: 00
1e83: R_X86_64_32S __per_cpu_offset
1e87: 31 c9 xor %ecx,%ecx
1e89: 87 0a xchg %ecx,(%rdx)
1e8b: 41 01 cb add %ecx,%r11d
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Diffstat (limited to 'fs/xfs')
| -rw-r--r-- | fs/xfs/xfs_log_cil.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index 2e9157b650e6..1ca406ec1b40 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -171,11 +171,8 @@ xlog_cil_insert_pcp_aggregate( */ for_each_cpu(cpu, &ctx->cil_pcpmask) { struct xlog_cil_pcp *cilpcp = per_cpu_ptr(cil->xc_pcp, cpu); - int old = READ_ONCE(cilpcp->space_used); - while (!try_cmpxchg(&cilpcp->space_used, &old, 0)) - ; - count += old; + count += xchg(&cilpcp->space_used, 0); } atomic_add(count, &ctx->space_used); } |