On Tue, Jan 24, 2017 at 11:02 PM, Chulmin Kim [off-list ref] wrote:

On 01/24/2017 03:16 PM, Dan Streetman wrote:

quoted

On Mon, Jan 23, 2017 at 7:03 PM, Alexandr [off-list ref] wrote:

quoted

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

quoted

Why would you do this?  There's no benefit of using zswap together
with zram.

i just wanted to test zram and zswap, i still not dig to deep in it,
but what i wanted is to use zram swap (with zswap disabled), and if it
exceeded use real swap on block device with zswap enabled.

I don't believe that's possible, you can't enable zswap for only
specific swap devices; and anyway, if you fill up zram, you won't
really have any memory left for zswap to use will you?

However, it shouldn't encounter any BUG(), like you saw.  If it's
reproducable for you, can you give details on how to reproduce it?

Hello. Mr. Streetman.


Regarding to this problem, I have a question on zswap.

Is there any reason that
zswap_frontswap_load() does not call flush_dcache_page()?

The zswap load function can dirty the page mapped to user space (might be
shareable/writable) which seems exactly the condition mentioned in the
definition of flush_dcache_page().

I'm thinking that
flush_dcache_page() should be called in the end of zswap_frontswap_load().
Could you review my opinion?

I don't think it needs to, as i detailed in my response to the other thread.

Also, this is a different issue, I think - even if there is a cache
problem with pages loaded from zswap, i don't see how it would cause a
decompression failure - the zpool storage is the only code that has a
copy of its compressed pages, no userspace or any other kernel code
should be accessing any of it.

Thanks!
Chulmin Kim

quoted

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>