On Thu, 04 Oct 2007 14:25:22 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:This description of the bug-which-is-being-fixed is nowhere near adequate enough for a reviewer to understand the problem. This makes it hard to suggest alternative fixes. That's described in the changelog for the patch which added throttle_vm_writeout(). Unsurprisingly ;) None of the above. [PATCH] vm: pageout throttling With silly pageout testcases it is possible to place huge amounts of memory under I/O. With a large request queue (CFQ uses 8192 requests) it is possible to place _all_ memory under I/O at the same time. This means that all memory is pinned and unreclaimable and the VM gets upset and goes oom. The patch limits the amount of memory which is under pageout writeout to be a little more than the amount of memory at which balance_dirty_pages() callers will synchronously throttle. This means that heavy pageout activity can starve heavy writeback activity completely, but heavy writeback activity will not cause starvation of pageout. Because we don't want a simple `dd' to be causing excessive latencies in page reclaim. afaict that problem is still there. It is possible to get all of ZONE_NORMAL dirty on a highmem machine. With a large queue (or lots of queues), vmscan can them place all of ZONE_NORMAL under IO. It could be that we've fixed this problem via other means in the interrim, but from a quick peek to seems to me that the scanner will still do a 100% CPU burn when all of a zone's pages are under writeback. throttle_vm_writeout() should be a per-zone thing, I guess. Perhaps fixing that would fix your deadlock. That's doubtful, but I don't know anything about your deadlock so I cannot say. -
| Arjan van de Ven | [patch] Add basic sanity checks to the syscall execution patch |
| Matthew Wilcox | Re: AIM7 40% regression with 2.6.26-rc1 |
| Bart Van Assche | Integration of SCST in the mainstream Linux kernel |
| Greg Kroah-Hartman | [PATCH 005/196] Chinese: add translation of SubmittingDrivers |
git: | |
| Andy Whitcroft | Re: VCS comparison table |
| David | User's mailing list? And multiple cherry pick |
| Scott Chacon | Git Community Book |
| Mark Levedahl | Re: [PATCH] Teach remote machinery about remotes.default config variable |
| Marco Peereboom | Re: Real men don't attack straw men |
| Richard Stallman | Real men don't attack straw men |
| GVG GVG | ssh_exchange_identification: Connection closed by remote host |
| Tony Abernethy | Re: What is our ultimate goal?? |
| Arjan van de Ven | Re: [GIT]: Networking |
| Jeff Garzik | Re: [bug?] tg3: Failed to load firmware "tigon/tg3_tso.bin" |
| Denys Fedoryshchenko | packetloss, on e1000e worse than r8169? |
| Radu Rendec | Endianness problem with u32 classifier hash masks |
