linux-kernel - PREEMPT is messing with everyone

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Date:	Tue, 5 Dec 2006 19:40:34 +0530
From:	"Jaswinder Singh" <jaswinderrajput@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: PREEMPT is messing with everyone

Hi,

preempt stuff SHOULD only stay in #ifdef CONFIG_PREEMP_* , but it is
messing with everyone even though not defined.

e.g.

1. linux-2.6.19/kernel/spinlock.c

Line 18: #include <linux/preempt.h>

Line 26:  preempt_disable();

Line 32:  preempt_disable();

and so on .

2. linux-2.6.19/kernel/sched.c

Line 1096:  int preempted;

Line 1104:   preempted = !task_running(rq, p);

Line 1106:   if (preempted)

Line 2059:  if (TASK_PREEMPTS_CURR(p, this_rq))

Line 3355:    current->comm, preempt_count(), current->pid);

Line 3342:  preempt_disable();

Line 3375:  if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {

Line 3471:  preempt_enable_no_resched();

3. linux-2.6.19/kernel/timer.c

Line 444:     int preempt_count = preempt_count();

Line 447:     if (preempt_count != preempt_count()) {

4. linux-2.6.19/arch/i386/kernel/entry.S

Line 240:  preempt_stop

5. linux-2.6.19/arch/i386/irq.c

Line 111:    irqctx->tinfo.preempt_count =

Line 112:    (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |

Line 113:    (curctx->tinfo.preempt_count & SOFTIRQ_MASK);

Line 160:  irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;

and so on.

Similarly unnecessary preempt code is also written in other important files.

70 to 80 % of this code is removed when compiled.

but 20 to 30 % code left in binary kernel image.

Why Linux kernel is wasting its resources which is not defined at all.

Any solution ?

Thank you,

Best Regards,

Jaswinder Singh.
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