On Tue, 14 Jul 2015 08:54:11 -0700 Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > My laptop has been behaving strangely with 4.2-rc2. Once I log in to my > X session, I start getting all kinds of strange errors from applications > and see this in my dmesg: > > VFS: file-max limit 8192 reached > > Could this be from CONFIG_DEFERRED_STRUCT_PAGE_INIT=y? files_init() > seems top be sizing files_stat.max_files from memory sizes. argh. > vfs_caches_init() uses nr_free_pages() to figure out what the "current > kernel size" is in early boot. *But* since we have not freed most of > our memory, nr_free_pages() is low and makes us calculate the reserve as > if the kernel we huge. > > Adding some printk's confirms this. Broken kernel: > > vfs_caches_init() mempages: 4026972 > vfs_caches_init() reserve: 4021629 > vfs_caches_init() mempages (after reserve minus): 5343 > files_init() n: 2137 > files_init() files_stat.max_files: 8192 > > Working kernel: > > vfs_caches_init() mempages: 4026972 > vfs_caches_init() reserve: 375 > vfs_caches_init() mempages2: 4026597 > files_init() n: 1610638 > files_init() files_stat.max_files: 1610638 > > Do we have an alternative to call instead of nr_free_pages() in > vfs_caches_init()? > > I guess we could save off 'nr_initialized' in memmap_init_zone() and > then use "nr_initialized - nr_free_pages()", but that seems a bit hackish. There are a lot of things that might be affected this way. Callers of nr_free_buffer_pages(), nr_free_pagecache_pages(), etc. If we'd fully used the memory hotplug infrastructure then everything would work - all those knobs which are sized off free-memory would get themselves resized as more memory comes on line. But quite a few things have been missed. -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>