Re: [patch] mm: rewrite vmap layer

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 18 Aug 2008 15:32:24 +0200 Nick Piggin <npiggin@suse.de> wrote:

> Rewrite the vmap allocator to use rbtrees and lazy tlb flushing, and provide a
> fast, scalable percpu frontend for small vmaps (requires a slightly different
> API, though).

With the full -mm lineup my ancient PIII machine is saying

calling agp_init+0x0/0x30
Linux agpgart interface v0.103
initcall agp_init+0x0/0x30 returned 0 after 0 msecs
calling agp_intel_init+0x0/0x30
agpgart-intel 0000:00:00.0: Intel 440BX Chipset
------------[ cut here ]------------
WARNING: at mm/vmalloc.c:105 vmap_page_range+0xea/0x130()
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.27-rc5-mm1 #1
 [<c0126404>] warn_on_slowpath+0x54/0x70
 [<c016dce9>] ? rmqueue_bulk+0x69/0x80
 [<c014666b>] ? trace_hardirqs_on+0xb/0x10
 [<c01465d4>] ? trace_hardirqs_on_caller+0xd4/0x160
 [<c016ece9>] ? get_page_from_freelist+0x229/0x4f0
 [<c018278a>] vmap_page_range+0xea/0x130
 [<c0182801>] map_vm_area+0x31/0x50
 [<c01828d4>] __vmalloc_area_node+0xb4/0x110
 [<c01829c9>] __vmalloc_node+0x99/0xa0
 [<c02c4040>] ? agp_add_bridge+0x1e0/0x4b0
 [<c02c4040>] ? agp_add_bridge+0x1e0/0x4b0
 [<c0182a23>] vmalloc+0x23/0x30
 [<c02c4040>] ? agp_add_bridge+0x1e0/0x4b0
 [<c02c4040>] agp_add_bridge+0x1e0/0x4b0
 [<c03d70c5>] agp_intel_probe+0x145/0x2d0
 [<c029f81e>] pci_device_probe+0x5e/0x80
 [<c02d4ef4>] driver_probe_device+0x84/0x180
 [<c02d5065>] __driver_attach+0x75/0x80
 [<c02d45a9>] bus_for_each_dev+0x49/0x70
 [<c029f760>] ? pci_device_remove+0x0/0x40
 [<c02d4d69>] driver_attach+0x19/0x20
 [<c02d4ff0>] ? __driver_attach+0x0/0x80
 [<c02d49ff>] bus_add_driver+0xaf/0x220
 [<c028e46f>] ? kset_find_obj+0x5f/0x80
 [<c029f760>] ? pci_device_remove+0x0/0x40
 [<c02d51ff>] driver_register+0x4f/0x120
 [<c02974a2>] ? __spin_lock_init+0x32/0x60
 [<c054f2c0>] ? agp_intel_init+0x0/0x30
 [<c029fa8b>] __pci_register_driver+0x5b/0xb0
 [<c054f2c0>] ? agp_intel_init+0x0/0x30
 [<c054f2e5>] agp_intel_init+0x25/0x30
 [<c010102a>] _stext+0x2a/0x150
 [<c054f2c0>] ? agp_intel_init+0x0/0x30
 [<c011deff>] ? wake_up_process+0xf/0x20
 [<c0135d3d>] ? start_workqueue_thread+0x1d/0x20
 [<c0136103>] ? __create_workqueue_key+0x143/0x190
 [<c0532732>] kernel_init+0x182/0x280
 [<c05325b0>] ? kernel_init+0x0/0x280
 [<c0103fff>] kernel_thread_helper+0x7/0x18
 =======================
---[ end trace e9106f0cfec79452 ]---
agpgart-intel 0000:00:00.0: can't allocate memory for key lists
agpgart-intel 0000:00:00.0: agp_backend_initialize() failed
agpgart-intel: probe of 0000:00:00.0 failed with error -12
initcall agp_intel_init+0x0/0x30 returned 0 after 10 msecs

: static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
: 		unsigned long end, pgprot_t prot, struct page **pages, int *nr)
: {
: 	pte_t *pte;
: 
: 	/*
: 	 * nr is a running index into the array which helps higher level
: 	 * callers keep track of where we're up to.
: 	 */
: 
: 	pte = pte_alloc_kernel(pmd, addr);
: 	if (!pte)
: 		return -ENOMEM;
: 	do {
: 		struct page *page = pages[*nr];
: 
: -->>		if (WARN_ON(!pte_none(*pte)))
: 			return -EBUSY;
: 		if (WARN_ON(!page))
: 			return -ENOMEM;
: 		set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
: 		(*nr)++;
: 	} while (pte++, addr += PAGE_SIZE, addr != end);
: 	return 0;
: }
: 

wanna take a look please?

config: http://userweb.kernel.org/~akpm/config-vmm.txt
dmesg: http://userweb.kernel.org/~akpm/dmesg-vmm.txt