Commit 1c80b990 authored by Andi Kleen's avatar Andi Kleen
Browse files

HWPOISON: Improve comments in memory-failure.c 



Clean up and improve the overview comment in memory-failure.c

Tidy some grammar issues in other comments.

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
parent 6b0cd00b

mm/memory-failure.c

+18 −13
Original line number Diff line number Diff line
@@ -7,21 +7,26 @@ 
 * Free Software Foundation.

 *

 * High level machine check handler. Handles pages reported by the

 * hardware as being corrupted usually due to a 2bit ECC memory or cache

 * hardware as being corrupted usually due to a multi-bit ECC memory or cache

 * failure.

 * 

 * In addition there is a "soft offline" entry point that allows stop using

 * not-yet-corrupted-by-suspicious pages without killing anything.

 *

 * Handles page cache pages in various states.	The tricky part

 * here is that we can access any page asynchronous to other VM

 * users, because memory failures could happen anytime and anywhere,

 * possibly violating some of their assumptions. This is why this code

 * has to be extremely careful. Generally it tries to use normal locking

 * rules, as in get the standard locks, even if that means the

 * error handling takes potentially a long time.

 * here is that we can access any page asynchronously in respect to 

 * other VM users, because memory failures could happen anytime and 

 * anywhere. This could violate some of their assumptions. This is why 

 * this code has to be extremely careful. Generally it tries to use 

 * normal locking rules, as in get the standard locks, even if that means 

 * the error handling takes potentially a long time.

 * 

 * The operation to map back from RMAP chains to processes has to walk

 * the complete process list and has non linear complexity with the number

 * mappings. In short it can be quite slow. But since memory corruptions

 * are rare we hope to get away with this.

 * 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 

 * has non linear complexity with the number. But since memory corruptions

 * are rare we hope to get away with this. This avoids impacting the core 

 * VM.

 */



/*
@@ -78,7 +83,7 @@ static int hwpoison_filter_dev(struct page *p) 
		return 0;



	/*

	 * page_mapping() does not accept slab page

	 * page_mapping() does not accept slab pages.

	 */

	if (PageSlab(p))

		return -EINVAL;