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authorRalf Baechle <ralf@linux-mips.org>2006-12-12 17:14:57 +0000
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-13 09:27:08 -0800
commitec8c0446b6e2b67b5c8813eb517f4bf00efa99a9 (patch)
treee7c12d7c486c958a5e38888b41cfcd6a558f1aff /Documentation
parentbcd022801ee514e28c32837f0b3ce18c775f1a7b (diff)
downloadop-kernel-dev-ec8c0446b6e2b67b5c8813eb517f4bf00efa99a9.zip
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[PATCH] Optimize D-cache alias handling on fork
Virtually index, physically tagged cache architectures can get away without cache flushing when forking. This patch adds a new cache flushing function flush_cache_dup_mm(struct mm_struct *) which for the moment I've implemented to do the same thing on all architectures except on MIPS where it's a no-op. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/cachetlb.txt23
1 files changed, 17 insertions, 6 deletions
diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt
index 53245c4..73e794f 100644
--- a/Documentation/cachetlb.txt
+++ b/Documentation/cachetlb.txt
@@ -179,10 +179,21 @@ Here are the routines, one by one:
lines associated with 'mm'.
This interface is used to handle whole address space
- page table operations such as what happens during
- fork, exit, and exec.
+ page table operations such as what happens during exit and exec.
+
+2) void flush_cache_dup_mm(struct mm_struct *mm)
+
+ This interface flushes an entire user address space from
+ the caches. That is, after running, there will be no cache
+ lines associated with 'mm'.
+
+ This interface is used to handle whole address space
+ page table operations such as what happens during fork.
+
+ This option is separate from flush_cache_mm to allow some
+ optimizations for VIPT caches.
-2) void flush_cache_range(struct vm_area_struct *vma,
+3) void flush_cache_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
Here we are flushing a specific range of (user) virtual
@@ -199,7 +210,7 @@ Here are the routines, one by one:
call flush_cache_page (see below) for each entry which may be
modified.
-3) void flush_cache_page(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn)
+4) void flush_cache_page(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn)
This time we need to remove a PAGE_SIZE sized range
from the cache. The 'vma' is the backing structure used by
@@ -220,7 +231,7 @@ Here are the routines, one by one:
This is used primarily during fault processing.
-4) void flush_cache_kmaps(void)
+5) void flush_cache_kmaps(void)
This routine need only be implemented if the platform utilizes
highmem. It will be called right before all of the kmaps
@@ -232,7 +243,7 @@ Here are the routines, one by one:
This routing should be implemented in asm/highmem.h
-5) void flush_cache_vmap(unsigned long start, unsigned long end)
+6) void flush_cache_vmap(unsigned long start, unsigned long end)
void flush_cache_vunmap(unsigned long start, unsigned long end)
Here in these two interfaces we are flushing a specific range
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