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Commit e0de78df authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

mm, hwpoison: add comment describing when to add new cases 



Here's another comment fix for hwpoison.

It describes the "guiding principle" on when to add new
memory error recovery code.

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Acked-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1ed58b60

mm/memory-failure.c

+8 −0
Original line number Diff line number Diff line
@@ -21,6 +21,14 @@ 
 * normal locking rules, as in get the standard locks, even if that means 

 * the error handling takes potentially a long time.

 *

 * It can be very tempting to add handling for obscure cases here.

 * In general any code for handling new cases should only be added iff:

 * - You know how to test it.

 * - You have a test that can be added to mce-test

 *   https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/

 * - The case actually shows up as a frequent (top 10) page state in

 *   tools/vm/page-types when running a real workload.

 * 

 * There are several operations here with exponential complexity because

 * of unsuitable VM data structures. For example the operation to map back 

 * from RMAP chains to processes has to walk the complete process list and