On Mon, 23 Jul 2007, Christoph Lameter wrote: > On Thu, 19 Jul 2007 18:35:17 +0100 (BST) > Hugh Dickins <[EMAIL PROTECTED]> wrote: > > > I didn't see any attention to set_page_dirty in Christoph's > > Large Blocksize (variable page_cachesize) patches, but I expect > > he'd also be wanting set_page_dirty to act on compound_head. > > There is no need for special casing if set_page_dirty() is only > ever called for page heads. Make sure that direct I/O does not call > set_page_dirty for tail pages. > > A VM_BUG_ON(PageTail(page)) could be used to make sure that this > does not happen in the future?
I expect we could take that approach in the current kernel, yes (though it would put those compound tests into the bio code that Jens was preferring to remove). But I think not if your variable page_cache_size went in: imagine an mmap of the tail component page of an order-1 page_cache_size page, and that pte only being dirtied: wouldn't set_page_dirty on that page need to redirect to the head? Hugh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/