On Mon, May 07, 2012 at 08:42:59PM -0700, Yinghai Lu wrote: >>>no, probe_resource will get from start if space is big enough. >>> >>>if not, it will try to extend top. >> >> Hmm... for example we still have this >> parent[70-160] >> brother1[70-80] res[90-150] brother2[151-160] >> ->child[105-140] >> >> if we call probe_resource(res, new_res, 16, par, 1, 0xff, >> IORESOURCE_PCI_FIXED); >> >> I think this call is used to allocate a res of size 16 under res. >> When there is no enough free space, it will expend res, and res->parent. >> >> While in this situation, res doesn't have enough free space. so it need >> to expend itself. >> >> In the probe_resource() it tries to extend res on the right side. >> So even there is enough space between brother1 and res, I think the >> probe_resource() will not return 0. >> >> Do you think my analysis is correct? > >it will reduce needed size one by one. so at last it will return >[91, 104] Yes, agree. This is the current behavior. While in this case. 70-160] brother1[70-80] res[90-150] brother151-160] ->child There is free space between 81-89, and 90-104. These two free range add up to 25, which is more than the required space, 16. If we have this resource tree. parent[70-180] brother1[70-80] re[90-150] brothr2[170-180] d[105-140] There are enough free space between res and brother2. Then probe_resource will return [141-156] with size 16. And also expend res. So I mean this is the design decision to not count in the free space on the left? Even there is enough free space? > >Yinghai -- Richard Yang Help you, Help me -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
