From: Benjamin Herrenschmidt <benh@kernel•crashing.org>
To: <linuxppc-dev@ozlabs•org>, <cbe-oss-dev@ozlabs•org>
Cc: Arnd Bergmann <arnd.bergmann@de•ibm.com>
Subject: [PATCH 2/5] This is a hack to get_unmapped_area to make the SPE 64K code work.
Date: Tue, 20 Feb 2007 18:44:13 +1100 [thread overview]
Message-ID: <20070220074432.D85DADDD0E@ozlabs.org> (raw)
In-Reply-To: <1171957452.861958.803775545202.qpush@grosgo>
(Though it might prove to not have nasty side effects ...)
The basic idea is that if the filesystem's get_unmapped_area was used,
we skip the hugepage check. That assumes that the only filesytems that
provide a g_u_a callback are either hugetlbfs itself, or filesystems
that have arch specific code that "knows" already not to collide with
hugetlbfs.
A proper fix will be done later, basically by removing the hugetlbfs
hacks completely from get_unmapped_area and calling down to the mm
and/or the filesytem g_u_a implementations for MAX_FIXED as well.
(Note that this will still rely on the fact that filesytems that
provide a g_u_a "know" how to return areas that don't collide with
hugetlbfs, thus the base assumption is the same as this hack)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel•crashing.org>
mm/mmap.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
Index: linux-cell/mm/mmap.c
===================================================================
--- linux-cell.orig/mm/mmap.c 2007-02-20 18:09:12.000000000 +1100
+++ linux-cell/mm/mmap.c 2007-02-20 18:10:08.000000000 +1100
@@ -1357,14 +1357,17 @@ unsigned long
get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
- unsigned long ret;
+ unsigned long ret = 0;
+ int fs_area = 0;
if (!(flags & MAP_FIXED)) {
unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
get_area = current->mm->get_unmapped_area;
- if (file && file->f_op && file->f_op->get_unmapped_area)
+ if (file && file->f_op && file->f_op->get_unmapped_area) {
get_area = file->f_op->get_unmapped_area;
+ fs_area = 1;
+ }
addr = get_area(file, addr, len, pgoff, flags);
if (IS_ERR_VALUE(addr))
return addr;
@@ -1380,7 +1383,7 @@ get_unmapped_area(struct file *file, uns
* can be made suitable for hugepages.
*/
ret = prepare_hugepage_range(addr, len, pgoff);
- } else {
+ } else if (!fs_area) {
/*
* Ensure that a normal request is not falling in a
* reserved hugepage range. For some archs like IA-64,
next prev parent reply other threads:[~2007-02-20 7:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-20 7:44 [PATCH 0/5] Support 64K pages mapping of SPE local stores on 4K kernel Benjamin Herrenschmidt
2007-02-20 7:44 ` [PATCH 1/5] powerpc: Fix spu SLB invalidations Benjamin Herrenschmidt
2007-02-20 7:44 ` Benjamin Herrenschmidt [this message]
2007-02-20 7:44 ` [PATCH 3/5] powerpc: Introduce address space "slices" Benjamin Herrenschmidt
2007-03-01 6:11 ` [PATCH] Allow spufs to build as a module with slices enabled Michael Ellerman
2007-03-02 2:15 ` [Cbe-oss-dev] " Christoph Hellwig
2007-03-02 4:10 ` Michael Ellerman
2007-02-20 7:44 ` [PATCH 4/5] powerpc: Add ability to 4K kernel to hash in 64K pages Benjamin Herrenschmidt
2007-02-20 7:44 ` [PATCH 5/5] powerpc: spufs support for 64K LS mappings on 4K kernels Benjamin Herrenschmidt
2007-03-01 7:29 ` [PATCH 0/5] Support 64K pages mapping of SPE local stores on 4K kernel Michael Ellerman
-- strict thread matches above, loose matches on Subject: below --
2007-03-02 11:32 Benjamin Herrenschmidt
2007-03-02 11:32 ` [PATCH 2/5] This is a hack to get_unmapped_area to make the SPE 64K code work Benjamin Herrenschmidt
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