vgoyal at redhat.com linux-kernel at vger.kernel.org, Eric Biederman <ebiederm at xmission.com> Bcc: ruyang at redhat.com Subject: Re: [PATCH v3 3/9] kexec_file: Factor out kexec_locate_mem_hole from kexec_add_buffer. Reply-To: In-Reply-To: <5428891.iJNV8CI1We at hactar> On 06/27/16 at 01:37pm, Thiago Jung Bauermann wrote: > Am Dienstag, 28 Juni 2016, 00:19:48 schrieb Dave Young: > > On 06/23/16 at 12:37pm, Thiago Jung Bauermann wrote: > > > Am Donnerstag, 23 Juni 2016, 01:44:07 schrieb Dave Young: > > > What is bad about the description of top_down? > > It is not clear enough to me, I personally think the original one in > > source code is better: > > /* allocate from top of memory hole */ > > Actually I realized there's some discrepancy in how the x86 code uses > top_down and how I need it to work in powerpc. This may be what is confusing > about my comment and the existing comment. > > x86 always walks memory from bottom to top but if top_down is true, in each > memory region it will allocate the memory hole in the highest address within > that region. I don't know why it is done that way, though. I think we did not meaning to do this, considering kdump we have only one crashkernel region for searching (crashk_res) so it is fine. For kexec maybe changing the walking function to accept top_down is reasonable. Ccing Vivek see if he can remember something.. > > On powerpc, the memory walk itself should be from top to bottom, as well as > the memory hole allocation within each memory region. > > Should I add a separate top_down argument to kexec_locate_mem_hole to > control if the memory walk should be from top to bottom, and then the > bottom_up member of struct kexec_buf controls where inside each memory > region the memory hole will be allocated? > > -- > []'s > Thiago Jung Bauermann > IBM Linux Technology Center > > > _______________________________________________ > kexec mailing list > kexec at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec Thanks Dave
