Re: [HACKERS] can shared cache be swapped to disk?

2011-01-05 Thread Dimitri Fontaine
Jeff Janes writes: > ("top" doesn't distinguish between memory that has been requested but > never accessed, versus memory that has been accessed and then truly > swapped out to disk. So unless you first let it run to steady-state > before applying pressure, it is hard to interpret the results.)

Re: [HACKERS] can shared cache be swapped to disk?

2011-01-04 Thread Jeff Janes
On Tue, Jan 4, 2011 at 2:52 PM, Martijn van Oosterhout wrote: > On Tue, Jan 04, 2011 at 09:51:05AM -0800, Jeff Janes wrote: >> > Correct. The kernel ignores locking requests because it's a great way >> > to DOS a machine. For example, mlock() of large blocks of memory is >> > also not permitted fo

Re: [HACKERS] can shared cache be swapped to disk?

2011-01-04 Thread Martijn van Oosterhout
On Tue, Jan 04, 2011 at 09:51:05AM -0800, Jeff Janes wrote: > > Correct. The kernel ignores locking requests because it's a great way > > to DOS a machine. For example, mlock() of large blocks of memory is > > also not permitted for similar reasons. > > Does it ignore such requests in general, or

Re: [HACKERS] can shared cache be swapped to disk?

2011-01-04 Thread Jeff Janes
On Sun, Dec 19, 2010 at 6:14 AM, Martijn van Oosterhout wrote: > On Sat, Dec 18, 2010 at 11:59:33PM -0800, Jeff Janes wrote: >> On Sat, Dec 18, 2010 at 10:11 PM, flyusa2010 fly >> wrote: >> > hi, folks! >> > I see that shared cache is implemented by system v shared memory. I wonder >> > whether

Re: [HACKERS] can shared cache be swapped to disk?

2010-12-19 Thread Martijn van Oosterhout
On Sat, Dec 18, 2010 at 11:59:33PM -0800, Jeff Janes wrote: > On Sat, Dec 18, 2010 at 10:11 PM, flyusa2010 fly wrote: > > hi, folks! > > I see that shared cache is implemented by system v shared memory. I wonder > > whether data in this area can be swapped out to disk. > > Isn't it bad that we rea

Re: [HACKERS] can shared cache be swapped to disk?

2010-12-19 Thread Jeff Janes
On Sat, Dec 18, 2010 at 10:11 PM, flyusa2010 fly wrote: > hi, folks! > I see that shared cache is implemented by system v shared memory. I wonder > whether data in this area can be swapped out to disk. > Isn't it bad that we read data from disk, put data in shared cache, and > finally data in shar

[HACKERS] can shared cache be swapped to disk?

2010-12-18 Thread flyusa2010 fly
hi, folks! I see that shared cache is implemented by system v shared memory. I wonder whether data in this area can be swapped out to disk. Isn't it bad that we read data from disk, put data in shared cache, and finally data in shared cache is swapped to disk again! Why not use shmctl(..SHM_LOCK.