On Fri, Feb 14, 2025 at 08:20:07AM -0800, Dave Hansen wrote: > On 2/14/25 05:46, Kirill A. Shutemov wrote: > >> It sounds like you're advocating for the "slow guest boot" option. > >> Kirill, can you remind us how fast a guest boots to the shell for > >> modestly-sized (say 256GB) memory with "accept_memory=eager" versus > >> "accept_memory=lazy"? IIRC, it was a pretty remarkable difference. > > I only have 128GB machine readily available and posted some number on > > other thread[1]: > > > > On single vCPU it takes about a minute to accept 90GiB of memory. > > > > It improves a bit with number of vCPUs. It is 40 seconds with 4 vCPU, but > > it doesn't scale past that in my setup. > > > > I've mentioned it before in other thread: > > > > [1] > > https://lore.kernel.org/all/ihzvi5pwn5hrn4ky2ehjqztjxoixaiaby4igmeihqfehy2vrii@tsg6j5qvmyrm > > Oh, wow, from that other thread, you've been trying to get this crash > fix accepted since November? > > From the looks of it, Eric stopped responding to that thread. I _think_ > you gave a reasonable explanation of why memory acceptance is slow. He > then popped back up last month raising security concerns. But I don't > see anyone that shares those concerns. > > The unaccepted memory stuff is also _already_ touching the page > allocator. If it's a dumb idea, then we should be gleefully ripping it > out of the page allocator, not rejecting a 2-line kexec patch. > > Baoquan has also said this looks good to him. > > I'm happy to give Eric another week to respond in case he's on vacation > or something, but I'm honestly not seeing a good reason to hold this bug > fix up. > > Andrew, is this the kind of thing you can stick into mm and hold on to > for a bit while we give Eric time to respond?
Andrew, Eric, can we get this patch in? -- Kiryl Shutsemau / Kirill A. Shutemov
