Re: No surprise on memory

2008-12-22 Thread Artem Bityutskiy
Jim Gettys wrote: Note that I'm not advocating in favor of soldered NAND - in fact I've been one of the leading proponents of migrating to an SD-based storage solution. I'm just pointing out that, if you're willing to buy an SD card now (which is necessary for the SD-based swap solution),

Re: No surprise on memory

2008-12-21 Thread Tomeu Vizoso
On Sat, Dec 20, 2008 at 23:57, Albert Cahalan acaha...@gmail.com wrote: [multiple people] I recently learned a few very important things about Linux memory management (I'm speaking about how its supposed to work, irrespective of any bugs). Operating systems experts already know all of this,

Re: No surprise on memory

2008-12-20 Thread Albert Cahalan
[multiple people] I recently learned a few very important things about Linux memory management (I'm speaking about how its supposed to work, irrespective of any bugs). Operating systems experts already know all of this, but I did not. This is a good reminder for those of us who tend to

Re: No surprise on memory

2008-12-18 Thread John Gilmore
What about using a NAND partition as swap? Has this ever been done? Given that partition support is a recent development it seems unlikely. Swapping to the soldered-in NAND chips is a very bad idea. It will tend to wear them out rapidly. Even if you use load-leveling software (e.g. swapping

Re: No surprise on memory

2008-12-18 Thread Martin Langhoff
On Thu, Dec 18, 2008 at 8:51 AM, John Gilmore g...@toad.com wrote: What about using a NAND partition as swap? Has this ever been done? Given that partition support is a recent development it seems unlikely. Swapping to the soldered-in NAND chips is a very bad idea. It will tend to wear them

Re: No surprise on memory

2008-12-18 Thread Chris Ball
Hi, Swapping to the soldered-in NAND chips is a very bad idea. It will tend to wear them out rapidly. Even if you use load-leveling software (e.g. swapping to a file in a jfffs2 filesystem), the problem is that While I generally agree with you,

Re: No surprise on memory

2008-12-18 Thread Carol Farlow Lerche
After reading Belyakov's paper a few questions for the experts occurred to me: Since Linux allows multiple swap partitions, is there anything to be gained by using two -- the first, a compcache swap file and the second on flash, perhaps with Belyakov's MTD layer. First question is whether Linux

Re: No surprise on memory

2008-12-18 Thread John Watlington
The soldered in NAND is also 14 times slower on writes and half the speed of a good SD card. wad On Dec 18, 2008, at 5:51 AM, John Gilmore wrote: What about using a NAND partition as swap? Has this ever been done? Given that partition support is a recent development it seems unlikely.

Re: No surprise on memory

2008-12-18 Thread Martin Langhoff
On Thu, Dec 18, 2008 at 1:43 PM, Carol Farlow Lerche c...@msbit.com wrote: Since Linux allows multiple swap partitions, is there anything to be gained by using two -- the first, a compcache swap file and the second on flash, perhaps with Belyakov's MTD layer. First question is whether Linux

Re: No surprise on memory

2008-12-18 Thread Carol Farlow Lerche
While the MTD layer does go to memory first, my thought about two swaps was slightly different. Depending on how they are managed, one of two things might happen: (I assume the second swap isn't used until the first is full) 1. less busy stuff gets migrated to the second swap or 2) The second

Re: No surprise on memory

2008-12-18 Thread Mitch Bradley
John Gilmore wrote: Swapping to the soldered-in NAND chips is a very bad idea. It will tend to wear them out rapidly. Even if you use load-leveling software (e.g. swapping to a file in a jfffs2 filesystem), the problem is that if you do start wearing out serious numbers of flash blocks, the

Re: No surprise on memory

2008-12-18 Thread Jim Gettys
On Thu, 2008-12-18 at 09:13 -1000, Mitch Bradley wrote: John Gilmore wrote: Swapping to the soldered-in NAND chips is a very bad idea. It will tend to wear them out rapidly. Even if you use load-leveling software (e.g. swapping to a file in a jfffs2 filesystem), the problem is that if

Re: No surprise on memory

2008-12-18 Thread Hal Murray
This isn't directly related to swapping, but if anybody is curious about flash technology... Al Fazio from Intel gave a good talk at Stanford EE380 last November. He had lots of details and numbers about flash technology. Good geek bait. Intel is selling flash based disks for laptops. They

Re: No surprise on memory

2008-12-16 Thread Benjamin Berg
On Mon, 2008-12-15 at 23:21 -0500, Benjamin M. Schwartz wrote: I'm no expert, but making the system work well without overcommit would probably require extensive modifications to the python interpreter, the fd.o libraries (dbus, gstreamer, telepathy, etc.), gecko, and maybe even X. All of

Re: No surprise on memory

2008-12-16 Thread Erik Garrison
On Tue, Dec 16, 2008 at 12:45:52PM -0200, Martin Langhoff wrote: On Tue, Dec 16, 2008 at 12:34 PM, Tomeu Vizoso to...@sugarlabs.org wrote: Well, I wasn't trying to give a solution, just suggested a less bad way to fail. IMO, just trying to find the perfect solution while not doing anything

Re: No surprise on memory

2008-12-16 Thread Tomeu Vizoso
On Tue, Dec 16, 2008 at 15:29, Martin Langhoff martin.langh...@gmail.com wrote: On Tue, Dec 16, 2008 at 12:19 PM, Tomeu Vizoso to...@sugarlabs.org wrote: I'm with Benjamin here, if the OOM killer kicked in soon enough and activities were clearly marked as first candidates to be killed,

Re: No surprise on memory

2008-12-16 Thread Tomeu Vizoso
2008/12/16 Benjamin Berg benja...@sipsolutions.net: On Mon, 2008-12-15 at 23:21 -0500, Benjamin M. Schwartz wrote: I'm no expert, but making the system work well without overcommit would probably require extensive modifications to the python interpreter, the fd.o libraries (dbus, gstreamer,

Re: No surprise on memory

2008-12-16 Thread Martin Langhoff
On Tue, Dec 16, 2008 at 1:40 PM, Erik Garrison e...@laptop.org wrote: What about using a NAND partition as swap? Has this ever been done? Given that partition support is a recent development it seems unlikely. There's been discussion on this list about it. I don't think the mtd driver does any

Re: No surprise on memory

2008-12-16 Thread Martin Langhoff
On Tue, Dec 16, 2008 at 12:34 PM, Tomeu Vizoso to...@sugarlabs.org wrote: Well, I wasn't trying to give a solution, just suggested a less bad way to fail. IMO, just trying to find the perfect solution while not doing anything to improve what we have now is the worst of the possibilities. Oh,

Re: No surprise on memory

2008-12-16 Thread Martin Langhoff
On Tue, Dec 16, 2008 at 12:19 PM, Tomeu Vizoso to...@sugarlabs.org wrote: I'm with Benjamin here, if the OOM killer kicked in soon enough and activities were clearly marked as first candidates to be killed, stability would be much much better. Combine that with Mac OS (pre X) style estimated

Re: No surprise on memory

2008-12-16 Thread Jameson Quinn
Erik, what is the latest status on Compcache? Obviously, this could relieve some of the pressure, but does not remove the need for an OOM strategy (or strategies). Jameson On Tue, Dec 16, 2008 at 11:38 AM, Martin Langhoff martin.langh...@gmail.com wrote: On Tue, Dec 16, 2008 at 1:40 PM, Erik

No surprise on memory

2008-12-15 Thread Benjamin M. Schwartz
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I recently learned a few very important things about Linux memory management (I'm speaking about how its supposed to work, irrespective of any bugs). Operating systems experts already know all of this, but I did not. 1. Malloc lies. It will happily

Re: No surprise on memory

2008-12-15 Thread quozl
On Mon, Dec 15, 2008 at 11:21:18PM -0500, Benjamin M. Schwartz wrote: I'm no expert, but making the system work well without overcommit would probably require extensive modifications to the python interpreter, the fd.o libraries (dbus, gstreamer, telepathy, etc.), gecko, and maybe even X. All