search for: vma_merg

.... However, the RW map is private dirty, > it cannot be merged with adjacent maps so I am not clear how it can save > kernel memory. > My understanding (and my test result shows so) is that two VMAs can be merged even when one of them contains dirty pages. As far as I can tell from reading vma_merge() in mm/mmap.c in Linux kernel, there's nothing preventing merging consecutively mmaped regions in that case. That said, we may not care about this case too much if we decide that this change should be put behind a flag, because in that case, I think we can just go with option 1. > > I...

...ages+0xcf/0x275 Aug 15 14:40:30 xen5etch kernel: [<c0288eec>] schedule+0x628/0x6e0 Aug 15 14:40:30 xen5etch kernel: [<c0146d2a>] follow_page+0x23b/0x312 Aug 15 14:40:30 xen5etch kernel: [<c0148fd6>] get_user_pages+0x375/0x474 Aug 15 14:40:30 xen5etch kernel: [<c014c258>] vma_merge+0xd3/0x142 Aug 15 14:40:30 xen5etch kernel: [<c014abbc>] make_pages_present+0x6f/0x84 Aug 15 14:40:30 xen5etch kernel: [<c014c6d0>] do_brk+0x1c5/0x1dd Aug 15 14:40:30 xen5etch kernel: [<c014c79b>] sys_brk+0xb3/0xd3 Aug 15 14:40:30 xen5etch kernel: [<c0104883>] syscall_c...

On Thu, Aug 29, 2019 at 3:10 AM Fāng-ruì Sòng <maskray at google.com> wrote: > Hello Vic, > > To make sure I understand the proposal correctly, do you propose: > > Old: R RX RW(RELRO) RW > New: R(R+RELRO) RX RW; R includes the traditional R part and the > RELRO part > Runtime (before relocation resolving): RW RX RW > Runtime (after relocation resolving): R RX

...ffff8114d763>] filemap_fault+0x25a/0x373 [584564.942316] [<ffffffff8116512b>] __do_fault+0x9f/0x3eb [584564.942328] [<ffffffff81168d62>] handle_mm_fault+0x420/0x88c [584564.942334] [<ffffffff8105d25f>] __do_page_fault+0x3cb/0x42a [584564.942338] [<ffffffff8116c577>] ? vma_merge+0x14f/0x227 [584564.942343] [<ffffffff8116d3df>] ? do_brk+0x21a/0x243 [584564.942347] [<ffffffff8105d2ff>] do_page_fault+0x22/0x27 [584564.942352] [<ffffffff81718e08>] page_fault+0x28/0x30 [584564.942354] Mem-Info: [584564.942356] DMA per-cpu: [584564.942359] CPU 0: hi:...