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HWPOISON: Improve comments in memory-failure.c

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

Tidy some grammar issues in other comments.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
This commit is contained in:
Andi Kleen 2010-09-27 23:09:51 +02:00
parent 6b0cd00bc3
commit 1c80b990a3
1 changed files with 18 additions and 13 deletions
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31
mm/memory-failure.c
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@ -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.
*
* 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.
* 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.
*
* 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;