On Sun, May 06, 2012 at 07:04:09PM -0700, Yinghai Lu wrote: >On Sun, May 6, 2012 at 6:17 PM, Richard Yang <weiyang@xxxxxxxxxxxxxxxxxx> wrote: >> so this free space will be combined with the free space got from >> parent, form a big space to meet the requirement. >> >> This is the general idea about probe_resource()? >> >> And this is the design decision to find the free space at the end >> of top, even at the start we have more free space? > >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? > >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