PATCH: Re: Helding the Kernel lock while doing IO???

["Juan J. Quintela" <quintela@fi.udc.es>]

>>>>> "stephen" == Stephen C Tweedie <sct@redhat.com> writes:

stephen> Hi,
stephen> On Sat, May 06, 2000 at 03:30:47AM +0200, Juan J. Quintela wrote:
>> 
>> read_swap_cache is called synchronously, then we can have to wait
>> until we read the page to liberate the lock kernel.  It is intended?
>> I am losing some detail?

stephen> Holding the big kernel lock while we sleep is quite legal.  The 
stephen> scheduler drops the lock while we sleep and reacquires it when we
stephen> are rescheduled.  The lock_kernel() lock is not at all like other
stephen> spinlocks.

Thanks again for the comment, what do you think about add a comment
about that?  Patch attached.

Later, Juan.

diff -urN --exclude-from=/home/lfcia/quintela/work/kernel/exclude work/include/linux/smp_lock.h testing/include/linux/smp_lock.h
--- work/include/linux/smp_lock.h	Sun May 14 20:20:41 2000
+++ testing/include/linux/smp_lock.h	Mon May 15 00:00:29 2000
@@ -5,6 +5,11 @@
 
 #ifndef CONFIG_SMP
 
+/* We can hold the big kernel lock while we sleep.  The scheduler
+ * drops the lock while we sleep and re-acquires it when we are
+ * rescheduled.  
+ */
+
 #define lock_kernel()				do { } while(0)
 #define unlock_kernel()				do { } while(0)
 #define release_kernel_lock(task, cpu)		do { } while(0)


-- 
In theory, practice and theory are the same, but in practice they 
are different -- Larry McVoy
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