2008/11/20 Nick Piggin <nickpiggin@xxxxxxxxxxxx>: > On Thursday 20 November 2008 23:28, Dmitry Adamushko wrote: >> 2008/11/20 Nick Piggin <nickpiggin@xxxxxxxxxxxx>: >> > [ ... ] >> > >> > - The page is sent to the block layer, which stores into the page. Some >> > block devices like 'brd' will potentially store via the kernel linear >> > map here, and they probably don't do enough cache flushing. >> >> btw., if someone is curious, here is another case of what may happen >> on VIPT systems when someone uses a "virtual" block device (like >> 'brd') as, heh, a swap :-) >> >> http://www.linux-mips.org/archives/linux-mips/2008-11/msg00038.html > > Right... Now I'm lacking knowledge when it comes to devices, but I > think it is probably reasonable for the block device layer to ensure > the physical memory is uptodate after it signals request completion. > > That is, there shouldn't be any potentially aliasing dirty lines. > Block devices which do any writeout via the kernel linear address > (eg. brd) should do a flush_dcache_page. > Yeah, but my point is that flush_dcache_page() in its current incarnation will _not_ always match the expectetions of such block devices (e.g. brd or compcache) when those devices are used as "swap" :-) IOW, although flush_dcache_page() is in place, it won't work as expected. -- Best regards, Dmitry Adamushko -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
