* [PATCH 2.5.62] Support for remap_page_range in objrmap
@ 2003-02-20 21:53 Dave McCracken
2003-02-20 23:10 ` Martin J. Bligh
0 siblings, 1 reply; 3+ messages in thread
From: Dave McCracken @ 2003-02-20 21:53 UTC (permalink / raw)
To: Andrew Morton; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 415 bytes --]
Here's the fix we discussed for remap_page_range. It sets the anon flag
for pages in any vma used for nonlinear. It also requires that
MAP_NONLINEAR be passed in at mmap time to flag the vma.
Dave
======================================================================
Dave McCracken IBM Linux Base Kernel Team 1-512-838-3059
dmccr@us.ibm.com T/L 678-3059
[-- Attachment #2: objrmap-2.5.62-4.diff --]
[-- Type: text/plain, Size: 4077 bytes --]
--- 2.5.62-objsent/./include/linux/mm.h 2003-02-19 12:00:47.000000000 -0600
+++ 2.5.62-objrmap/./include/linux/mm.h 2003-02-20 13:14:08.000000000 -0600
@@ -107,6 +107,7 @@
#define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */
#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
+#define VM_NONLINEAR 0x00800000 /* Nonlinear area */
#ifdef CONFIG_STACK_GROWSUP
#define VM_STACK_FLAGS (VM_GROWSUP | VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT)
--- 2.5.62-objsent/./include/asm-i386/mman.h 2003-02-17 16:55:56.000000000 -0600
+++ 2.5.62-objrmap/./include/asm-i386/mman.h 2003-02-20 13:28:23.000000000 -0600
@@ -20,6 +20,7 @@
#define MAP_NORESERVE 0x4000 /* don't check for reservations */
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
+#define MAP_NONLINEAR 0x20000 /* will be used for remap_file_pages */
#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_INVALIDATE 2 /* invalidate the caches */
--- 2.5.62-objsent/./mm/fremap.c 2003-02-17 16:55:50.000000000 -0600
+++ 2.5.62-objrmap/./mm/fremap.c 2003-02-20 15:35:25.000000000 -0600
@@ -78,6 +78,8 @@
if (prot & PROT_WRITE)
entry = pte_mkwrite(pte_mkdirty(entry));
set_pte(pte, entry);
+ if (vma->vm_flags & VM_NONLINEAR)
+ SetPageAnon(page);
pte_chain = page_add_rmap(page, pte, pte_chain);
pte_unmap(pte);
flush_tlb_page(vma, addr);
@@ -133,7 +135,8 @@
* and that the remapped range is valid and fully within
* the single existing vma:
*/
- if (vma && (vma->vm_flags & VM_SHARED) &&
+ if (vma &&
+ ((vma->vm_flags & (VM_SHARED|VM_NONLINEAR)) == (VM_SHARED|VM_NONLINEAR)) &&
vma->vm_ops && vma->vm_ops->populate &&
end > start && start >= vma->vm_start &&
end <= vma->vm_end) {
--- 2.5.62-objsent/./mm/mmap.c 2003-02-17 16:56:19.000000000 -0600
+++ 2.5.62-objrmap/./mm/mmap.c 2003-02-20 13:41:20.000000000 -0600
@@ -219,6 +219,7 @@
flag_bits =
_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) |
_trans(flags, MAP_DENYWRITE, VM_DENYWRITE) |
+ _trans(flags, MAP_NONLINEAR, VM_NONLINEAR) |
_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE);
return prot_bits | flag_bits;
#undef _trans
--- 2.5.62-objsent/./mm/rmap.c 2003-02-19 12:05:48.000000000 -0600
+++ 2.5.62-objrmap/./mm/rmap.c 2003-02-20 13:53:57.000000000 -0600
@@ -111,20 +111,20 @@
goto out;
}
pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd)) {
+ if (!pgd_present(*pgd))
goto out_unlock;
- }
+
pmd = pmd_offset(pgd, address);
- if (!pmd_present(*pmd)) {
+ if (!pmd_present(*pmd))
goto out_unlock;
- }
+
pte = pte_offset_map(pmd, address);
- if (!pte_present(*pte)) {
+ if (!pte_present(*pte))
goto out_unmap;
- }
- if (page_to_pfn(page) != pte_pfn(*pte)) {
+
+ if (page_to_pfn(page) != pte_pfn(*pte))
goto out_unmap;
- }
+
if (ptep_test_and_clear_young(pte))
referenced++;
out_unmap:
@@ -156,13 +156,11 @@
if (down_trylock(&mapping->i_shared_sem))
return 1;
- list_for_each_entry(vma, &mapping->i_mmap, shared) {
+ list_for_each_entry(vma, &mapping->i_mmap, shared)
referenced += page_referenced_obj_one(vma, page);
- }
- list_for_each_entry(vma, &mapping->i_mmap_shared, shared) {
+ list_for_each_entry(vma, &mapping->i_mmap_shared, shared)
referenced += page_referenced_obj_one(vma, page);
- }
up(&mapping->i_shared_sem);
@@ -444,20 +442,19 @@
goto out;
}
pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd)) {
+ if (!pgd_present(*pgd))
goto out_unlock;
- }
+
pmd = pmd_offset(pgd, address);
- if (!pmd_present(*pmd)) {
+ if (!pmd_present(*pmd))
goto out_unlock;
- }
+
pte = pte_offset_map(pmd, address);
- if (!pte_present(*pte)) {
+ if (!pte_present(*pte))
goto out_unmap;
- }
- if (page_to_pfn(page) != pte_pfn(*pte)) {
+
+ if (page_to_pfn(page) != pte_pfn(*pte))
goto out_unmap;
- }
if (vma->vm_flags & VM_LOCKED) {
ret = SWAP_FAIL;
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2.5.62] Support for remap_page_range in objrmap
2003-02-20 21:53 [PATCH 2.5.62] Support for remap_page_range in objrmap Dave McCracken
@ 2003-02-20 23:10 ` Martin J. Bligh
2003-02-21 3:43 ` Rik van Riel
0 siblings, 1 reply; 3+ messages in thread
From: Martin J. Bligh @ 2003-02-20 23:10 UTC (permalink / raw)
To: Dave McCracken, Andrew Morton; +Cc: Linux Memory Management
> Here's the fix we discussed for remap_page_range. It sets the anon flag
> for pages in any vma used for nonlinear. It also requires that
> MAP_NONLINEAR be passed in at mmap time to flag the vma.
Using the page based mechanism might also clear up some people's
concerns about small windows onto large shared areas for Oracle,
which will probably be using these nonlinear mappings anyway.
Yes, I'm sure there are other corner cases that need to be addressed
as well ;-)
M.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2.5.62] Support for remap_page_range in objrmap
2003-02-20 23:10 ` Martin J. Bligh
@ 2003-02-21 3:43 ` Rik van Riel
0 siblings, 0 replies; 3+ messages in thread
From: Rik van Riel @ 2003-02-21 3:43 UTC (permalink / raw)
To: Martin J. Bligh; +Cc: Dave McCracken, Andrew Morton, Linux Memory Management
On Thu, 20 Feb 2003, Martin J. Bligh wrote:
> > Here's the fix we discussed for remap_page_range. It sets the anon flag
> > for pages in any vma used for nonlinear. It also requires that
> > MAP_NONLINEAR be passed in at mmap time to flag the vma.
>
> Using the page based mechanism might also clear up some people's
> concerns about small windows onto large shared areas for Oracle,
> which will probably be using these nonlinear mappings anyway.
Good point. Object based reverse mappings become unwieldy at about
the same point where the objects themselves get unwieldy.
A hybrid system with object based mappings in some cases and page
based mappings in other cases might work very nicely...
> Yes, I'm sure there are other corner cases that need to be addressed
> as well ;-)
There are, but at the moment I can't remember any as serious as the
"1000 tasks with 1000 small mappings of the same shared memory segment"
scenario.
This hybrid system looks like it is worth exploring.
regards,
Rik
--
Engineers don't grow up, they grow sideways.
http://www.surriel.com/ http://kernelnewbies.org/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2003-02-21 3:43 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2003-02-20 21:53 [PATCH 2.5.62] Support for remap_page_range in objrmap Dave McCracken
2003-02-20 23:10 ` Martin J. Bligh
2003-02-21 3:43 ` Rik van Riel
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox