LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* issue with patch "x86: no CPA on iounmap"
@ 2008-02-05  1:13 Siddha, Suresh B
  2008-02-05  4:41 ` Arjan van de Ven
  2008-02-05  4:48 ` Arjan van de Ven
  0 siblings, 2 replies; 6+ messages in thread
From: Siddha, Suresh B @ 2008-02-05  1:13 UTC (permalink / raw)
  To: tglx, mingo; +Cc: linux-kernel, arjan

This is wrt to x86 git commit f56d005d30342a45d8af2b75ecccc82200f09600
	"x86: no CPA on iounmap"

This can use performance issue. When a GART driver unmaps a RAM page,
which was mapped as UC, this commit will still retain UC attribute
on the kernel identity mapping. This can cause mysterious performance issue
if this freed page gets used by kernel later.

For now we should change the attribute during iounmap and in future PAT
infrastructure will have necessary hooks to avoid the aliasing issues.

thanks,
suresh

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2008-02-07 20:13 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-02-05  1:13 issue with patch "x86: no CPA on iounmap" Siddha, Suresh B
2008-02-05  4:41 ` Arjan van de Ven
2008-02-05  4:48 ` Arjan van de Ven
2008-02-05  7:05   ` Ingo Molnar
2008-02-05  7:14     ` Arjan van de Ven
2008-02-07 20:02     ` Siddha, Suresh B

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).