于 2013年02月16日 05:39, Julian Anastasov 写道: > > Hello, > > On Thu, 14 Feb 2013, Andrew Morton wrote: > >> On Thu, 7 Feb 2013 10:40:26 +0200 (EET) >> Julian Anastasov <ja@xxxxxx> wrote: >> >>>> Another question about the sysctl_sync_qlen_max: >>>> This variable is assigned as: >>>> >>>> ipvs->sysctl_sync_qlen_max = nr_free_buffer_pages() / 32; >>>> >>>> The function nr_free_buffer_pages actually means: counts of pages >>>> which are beyond high watermark within ZONE_DMA and ZONE_NORMAL. >>>> >>>> is it ok to be called here? Some people misused this function because >>>> the function name was misleading them. I am sorry I am totally not >>>> familiar with the ipvs code, so I am just asking you about >>>> this. >>> >>> Using nr_free_buffer_pages should be fine here. >>> We are using it as rough estimation for the number of sync >>> buffers we can use in NORMAL zones. We are using dev->mtu >>> for such buffers, so it can take a PAGE_SIZE for a buffer. >>> We are not interested in HIGHMEM size. high watermarks >>> should have negliable effect. I'm even not sure whether >>> we need to clamp it for systems with TBs of memory. >> >> Using nr_free_buffer_pages() is good-enough-for-now. There are >> questions around the name of this thing and its exact functionality and >> whether callers are using it appropriately. But if anything is changed >> there, it will be as part of kernel-wide sweep. >> >> One thing to bear in mind is memory hot[un]plug. Anything which was >> sized using nr_free_buffer_pages() (or similar) may become >> inappropriately sized if memory is added or removed. So any site which >> uses nr_free_buffer_pages() really should be associated with a hotplug >> handler and a great pile of code to resize the structure at runtime. >> It's pretty ugly stuff :( I suspect it usually Just Doesn't Matter. > > I'll try to think on this hotplug problem > and also on the si_meminfo usage in net/netfilter/ipvs/ip_vs_ctl.c > which is quite wrong for systems with HIGHMEM, may be > we need there a free+reclaimable+file function for > NORMAL zone. > >> Redarding this patch: >> net-change-type-of-netns_ipvs-sysctl_sync_qlen_max.patch and >> net-fix-functions-and-variables-related-to-netns_ipvs-sysctl_sync_qlen_max.patch >> are joined at the hip and should be redone as a single patch with a >> suitable changelog, please. And with a cc:netdev@xxxxxxxxxxxxxxx. > > Agreed, Zhang Yanfei and Simon? I'm just not sure, > may be this combined patch should hit only the > ipvs->nf->net trees? Or may be net-next, if we don't have > time for 3.8. > Should I resend the combined patch? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href