From: Christoph Lameter <clameter@sgi.com>
To: unlisted-recipients:; (no To-header on input)
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [09/17] VFALLBACK: Debugging aid
Date: Tue, 25 Sep 2007 16:42:13 -0700 [thread overview]
Message-ID: <20070925234251.272511860@sgi.com> (raw)
In-Reply-To: 20070925234204.546836393@sgi.com
[-- Attachment #1: vcompound_debugging_aid --]
[-- Type: text/plain, Size: 1881 bytes --]
Virtual fallbacks are rare and thus subtle bugs may creep in if we do not
test the fallbacks. CONFIG_VFALLBACK_ALWAYS makes all GFP_VFALLBACK
allocations fall back to virtual mapping.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
---
lib/Kconfig.debug | 11 +++++++++++
mm/page_alloc.c | 6 ++++++
2 files changed, 17 insertions(+)
Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c 2007-09-24 18:48:03.000000000 -0700
+++ linux-2.6/mm/page_alloc.c 2007-09-24 18:58:52.000000000 -0700
@@ -1208,6 +1208,12 @@ zonelist_scan:
}
}
+#ifdef CONFIG_VFALLBACK_ALWAYS
+ if ((gfp_mask & __GFP_VFALLBACK) &&
+ system_state == SYSTEM_RUNNING)
+ return vcompound_alloc(gfp_mask, order,
+ zonelist, alloc_flags);
+#endif
page = buffered_rmqueue(zonelist, zone, order, gfp_mask);
if (page)
break;
Index: linux-2.6/lib/Kconfig.debug
===================================================================
--- linux-2.6.orig/lib/Kconfig.debug 2007-09-24 18:30:45.000000000 -0700
+++ linux-2.6/lib/Kconfig.debug 2007-09-24 18:48:06.000000000 -0700
@@ -105,6 +105,17 @@ config DETECT_SOFTLOCKUP
can be detected via the NMI-watchdog, on platforms that
support it.)
+config VFALLBACK_ALWAYS
+ bool "Always fall back to Virtual Compound pages"
+ default y
+ help
+ Virtual compound pages are only allocated if there is no linear
+ memory available. They are a fallback and errors created by the
+ use of virtual mappings instead of linear ones may not surface
+ because of their infrequent use. This option makes every
+ allocation that allows a fallback to a virtual mapping use
+ the virtual mapping. May have a significant performance impact.
+
config SCHED_DEBUG
bool "Collect scheduler debugging info"
depends on DEBUG_KERNEL && PROC_FS
--
next prev parent reply other threads:[~2007-09-25 23:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-25 23:42 [00/17] Virtual Compound Page Support V1 Christoph Lameter
2007-09-25 23:42 ` [01/17] Vmalloc: Move vmalloc_to_page to mm/vmalloc Christoph Lameter
2007-09-25 23:42 ` [02/17] vmalloc: add const Christoph Lameter
2007-09-25 23:42 ` [03/17] i386: Resolve dependency of asm-i386/pgtable.h on highmem.h Christoph Lameter
2007-09-25 23:42 ` [04/17] is_vmalloc_addr(): Check if an address is within the vmalloc boundaries Christoph Lameter
2007-09-25 23:42 ` [05/17] vmalloc: clean up page array indexing Christoph Lameter
2007-09-25 23:42 ` [06/17] vunmap: return page array passed on vmap() Christoph Lameter
2007-09-25 23:42 ` [07/17] vmalloc_address(): Determine vmalloc address from page struct Christoph Lameter
2007-09-25 23:42 ` [08/17] GFP_VFALLBACK: Allow fallback of compound pages to virtual mappings Christoph Lameter
2007-09-25 23:42 ` Christoph Lameter [this message]
2007-09-25 23:42 ` [10/17] Use GFP_VFALLBACK for sparsemem Christoph Lameter
2007-09-25 23:42 ` [11/17] GFP_VFALLBACK for zone wait table Christoph Lameter
2007-09-25 23:42 ` [12/17] Virtual Compound page allocation from interrupt context Christoph Lameter
2007-09-25 23:42 ` [13/17] Virtual compound page freeing in " Christoph Lameter
2007-09-28 4:52 ` KAMEZAWA Hiroyuki
2007-09-28 17:35 ` Christoph Lameter
2007-09-28 23:58 ` KAMEZAWA Hiroyuki
2007-09-25 23:42 ` [14/17] Allow bit_waitqueue to wait on a bit in a vmalloc area Christoph Lameter
2007-09-25 23:42 ` [15/17] SLUB: Support virtual fallback via SLAB_VFALLBACK Christoph Lameter
2007-09-25 23:42 ` [16/17] Allow virtual fallback for buffer_heads Christoph Lameter
2007-09-25 23:42 ` [17/17] Allow virtual fallback for dentries Christoph Lameter
-- strict thread matches above, loose matches on Subject: below --
2007-09-19 3:36 [00/17] [RFC] Virtual Compound Page Support Christoph Lameter
2007-09-19 3:36 ` [09/17] VFALLBACK: Debugging aid Christoph Lameter
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