Messages in this thread | | | Date | Wed, 13 Dec 2006 00:45:50 -0800 | From | Suleiman Souhlal <> | Subject | Re: [patch 03/13] io-accounting: write accounting |
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akpm@osdl.org wrote: > From: Andrew Morton <akpm@osdl.org> > > Accounting writes is fairly simple: whenever a process flips a page from clean > to dirty, we accuse it of having caused a write to underlying storage of > PAGE_CACHE_SIZE bytes.
On architectures where dirtying a page doesn't cause a page fault (like i386), couldn't you end up billing the wrong process (in fact, I think that even on other archituctures set_page_dirty() doesn't get called immediately in the page fault handler)?
AFAICS, set_page_dirty() is mostly called when trying to unmap a page when trying to shrink LRU lists, and there is no guarantee that this happens under the process that dirtied it (in fact, the set_page_dirty() is often done by kswapd).
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