[Monetdb-developers] [Monetdb-checkins] MonetDB/src/gdk gdk_posix.mx, Feb2010, 1.176.2.14, 1.176.2.15

Martin Kersten Martin.Kersten at cwi.nl
Mon Feb 15 11:09:04 CET 2010


Stefan Manegold wrote:
> On Sun, Feb 14, 2010 at 09:23:10PM +0000, Martin Kersten wrote:
>> Update of /cvsroot/monetdb/MonetDB/src/gdk
>> In directory sfp-cvsdas-1.v30.ch3.sourceforge.com:/tmp/cvs-serv28118
>>
>> Modified Files:
>>       Tag: Feb2010
>> 	gdk_posix.mx 
>> Log Message:
>> Move the load advice outside the lock. 
> 
> FYI:
> This checkin also changes the semantics of MT_mmap_inform() such that, now,
> (1) with preload > 0, posix_madvise(base, len, advise) is also called on
>     areas that are not maintained in MT_mmap_tab[]
Indeed. There is no reason at this moment to bind it exclusively to mmap-tab
> (2) with preload < 0, posix_madvise(base, len, BUF_NORMAL) is never called
>     on areas that are not maintained in MT_mmap_tab[]
should be indeed.
But more experimentation is needed to separate the role of MT_mmap_tab
and general posix advice.

> 
> Was this intended?
> 
> Stefan
> 
>> Index: gdk_posix.mx
>> ===================================================================
>> RCS file: /cvsroot/monetdb/MonetDB/src/gdk/gdk_posix.mx,v
>> retrieving revision 1.176.2.14
>> retrieving revision 1.176.2.15
>> diff -u -d -r1.176.2.14 -r1.176.2.15
>> --- gdk_posix.mx	14 Feb 2010 13:17:50 -0000	1.176.2.14
>> +++ gdk_posix.mx	14 Feb 2010 21:22:29 -0000	1.176.2.15
>> @@ -884,7 +884,7 @@
>>  void
>>  MT_mmap_inform(void *base, size_t len, int preload, int advise, int writable)
>>  {
>> -	int i;
>> +	int i, unload =0;
>>  
>>  	(void) pthread_mutex_lock(&MT_mmap_lock);
>>  	i = MT_mmap_idx(base, len);
>> @@ -892,12 +892,13 @@
>>  		if (writable) MT_mmap_tab[i].writable = (writable > 0);
>>  		MT_mmap_tab[i].random += preload * (advise == BUF_WILLNEED); /* done as a counter to keep track of multiple threads */
>>  		MT_mmap_tab[i].usecnt += preload; /* active thread count */
>> -		if (preload > 0) 
>> -			(void) posix_madvise(base, len, advise);
>> -		else if (MT_mmap_tab[i].usecnt == 0) 
>> -			(void) posix_madvise(base, len, BUF_NORMAL);
>> +		unload = MT_mmap_tab[i].usecnt == 0;
>>  	}
>>  	(void) pthread_mutex_unlock(&MT_mmap_lock);
>> +	if (preload > 0) 
>> +		(void) posix_madvise(base, len, advise);
>> +	else if (unload)
>> +		(void) posix_madvise(base, len, BUF_NORMAL);
>>  
>>  }
>>  
>>
>>
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> 





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