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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2020-08-19 22:55:05 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 13:41:58 +0300 |
| commit | 01ccf592362a984534371b3596d4c953da6a7bb2 (patch) | |
| tree | 27cda671f00ea1ffd9a2712b00685104ef815b5a /include/linux/sched.h | |
| parent | 1724b95b92979a8ea8e55a4817d05b3bb7750958 (diff) | |
| download | linux-01ccf592362a984534371b3596d4c953da6a7bb2.tar.xz | |
sched: Bring the PF_IO_WORKER and PF_WQ_WORKER bits closer together
The bits PF_IO_WORKER and PF_WQ_WORKER are tested together in
sched_submit_work() which is considered to be a hot path.
If the two bits cross the 8 or 16 bit boundary then most architecture
require multiple load instructions in order to create the constant
value. Also, such a value can not be encoded within the compare opcode.
By moving the bit definition within the same block, the compiler can
create/use one immediate value.
For some reason gcc-10 on ARM64 requires both bits to be next to each
other in order to issue "tst reg, val; bne label". Otherwise the result
is "mov reg1, val; tst reg, reg1; bne label".
Move PF_VCPU out of the way so that PF_IO_WORKER can be next to
PF_WQ_WORKER.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200819195505.y3fxk72sotnrkczi@linutronix.de
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 93ecd930efd3..2bf0af19a62a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1489,9 +1489,10 @@ extern struct pid *cad_pid; /* * Per process flags */ +#define PF_VCPU 0x00000001 /* I'm a virtual CPU */ #define PF_IDLE 0x00000002 /* I am an IDLE thread */ #define PF_EXITING 0x00000004 /* Getting shut down */ -#define PF_VCPU 0x00000010 /* I'm a virtual CPU */ +#define PF_IO_WORKER 0x00000010 /* Task is an IO worker */ #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */ #define PF_FORKNOEXEC 0x00000040 /* Forked but didn't exec */ #define PF_MCE_PROCESS 0x00000080 /* Process policy on mce errors */ @@ -1515,7 +1516,6 @@ extern struct pid *cad_pid; #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ #define PF_MEMALLOC_NOCMA 0x10000000 /* All allocation request will have _GFP_MOVABLE cleared */ -#define PF_IO_WORKER 0x20000000 /* Task is an IO worker */ #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */ #define PF_SUSPEND_TASK 0x80000000 /* This thread called freeze_processes() and should not be frozen */ |