__get_free_pages() calls alloc_pages, finds the page_address() and
throws away the struct page *. Slab then calls virt_to_page to get it
back again. Much more efficient for slab to call alloc_pages itself,
as well as making the NUMA and non-NUMA cases more similarr to each other.
Signed-off-by: Matthew Wilcox <[email protected]>
Index: linux-2.6/mm/slab.c
===================================================================
RCS file: /var/cvs/linux-2.6/mm/slab.c,v
retrieving revision 1.29
diff -u -p -r1.29 slab.c
--- linux-2.6/mm/slab.c 12 Jan 2005 20:18:07 -0000 1.29
+++ linux-2.6/mm/slab.c 24 Jan 2005 16:47:02 -0000
@@ -894,16 +894,13 @@ static void *kmem_getpages(kmem_cache_t
flags |= cachep->gfpflags;
if (likely(nodeid == -1)) {
- addr = (void*)__get_free_pages(flags, cachep->gfporder);
- if (!addr)
- return NULL;
- page = virt_to_page(addr);
+ page = alloc_pages(flags, cachep->gfporder);
} else {
page = alloc_pages_node(nodeid, flags, cachep->gfporder);
- if (!page)
- return NULL;
- addr = page_address(page);
}
+ if (!page)
+ return NULL;
+ addr = page_address(page);
i = (1 << cachep->gfporder);
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
--
"Next the statesmen will invent cheap lies, putting the blame upon
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince
himself that the war is just, and will thank God for the better sleep
he enjoys after this process of grotesque self-deception." -- Mark Twain
Matthew Wilcox <[email protected]> wrote:
> __get_free_pages() calls alloc_pages, finds the page_address() and
> throws away the struct page *. Slab then calls virt_to_page to get it
> back again. Much more efficient for slab to call alloc_pages itself,
> as well as making the NUMA and non-NUMA cases more similarr to each other.
Looks reasonable. Should also work in the NOMMU case.
David
Matthew Wilcox wrote:
>__get_free_pages() calls alloc_pages, finds the page_address() and
>throws away the struct page *. Slab then calls virt_to_page to get it
>back again. Much more efficient for slab to call alloc_pages itself,
>as well as making the NUMA and non-NUMA cases more similarr to each other.
>
>Signed-off-by: Matthew Wilcox <[email protected]>
>
>
>
Signed-off-by: Manfred Spraul <[email protected]>
>Index: linux-2.6/mm/slab.c
>===================================================================
>RCS file: /var/cvs/linux-2.6/mm/slab.c,v
>retrieving revision 1.29
>diff -u -p -r1.29 slab.c
>--- linux-2.6/mm/slab.c 12 Jan 2005 20:18:07 -0000 1.29
>+++ linux-2.6/mm/slab.c 24 Jan 2005 16:47:02 -0000
>@@ -894,16 +894,13 @@ static void *kmem_getpages(kmem_cache_t
>
> flags |= cachep->gfpflags;
> if (likely(nodeid == -1)) {
>- addr = (void*)__get_free_pages(flags, cachep->gfporder);
>- if (!addr)
>- return NULL;
>- page = virt_to_page(addr);
>+ page = alloc_pages(flags, cachep->gfporder);
> } else {
> page = alloc_pages_node(nodeid, flags, cachep->gfporder);
>- if (!page)
>- return NULL;
>- addr = page_address(page);
> }
>+ if (!page)
>+ return NULL;
>+ addr = page_address(page);
>
> i = (1 << cachep->gfporder);
> if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
>
>
>
diff -urN linux-2.6.11-rc2-bk/mm/slab.c linux/mm/slab.c
--- linux-2.6.11-rc2-bk/mm/slab.c 2005-01-22 01:58:25.000000000 -0500
+++ linux/mm/slab.c 2005-01-24 15:35:08.000000000 -0500
@@ -893,17 +893,11 @@
int i;
flags |= cachep->gfpflags;
- if (likely(nodeid == -1)) {
- addr = (void*)__get_free_pages(flags, cachep->gfporder);
- if (!addr)
- return NULL;
- page = virt_to_page(addr);
- } else {
- page = alloc_pages_node(nodeid, flags, cachep->gfporder);
- if (!page)
- return NULL;
- addr = page_address(page);
- }
+
+ page = alloc_pages_node(nodeid, flags, cachep->gfporder);
+ if (!page)
+ return NULL;
+ addr = page_address(page);
i = (1 << cachep->gfporder);
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
@@ -2065,7 +2059,7 @@
if (unlikely(!ac->avail)) {
int x;
- x = cache_grow(cachep, flags, -1);
+ x = cache_grow(cachep, flags, numa_node_id());
// cache_grow can reenable interrupts, then ac could change.
ac = ac_data(cachep);
On Mon, Jan 24, 2005 at 07:58:03PM -0500, Brian Gerst wrote:
> Matthew Wilcox wrote:
> >__get_free_pages() calls alloc_pages, finds the page_address() and
> >throws away the struct page *. Slab then calls virt_to_page to get it
> >back again. Much more efficient for slab to call alloc_pages itself,
> >as well as making the NUMA and non-NUMA cases more similarr to each other.
>
> Here is a better patch:
I disagree. This disables the alloc_pages_current() optimisation.
I considered this option and rejected it.
> Remove the special case of nodeid == -1. Instead, use numa_node_id()
> when calling cache_grow().
>
> Signed-off-by: Brian Gerst <[email protected]>
> diff -urN linux-2.6.11-rc2-bk/mm/slab.c linux/mm/slab.c
> --- linux-2.6.11-rc2-bk/mm/slab.c 2005-01-22 01:58:25.000000000 -0500
> +++ linux/mm/slab.c 2005-01-24 15:35:08.000000000 -0500
> @@ -893,17 +893,11 @@
> int i;
>
> flags |= cachep->gfpflags;
> - if (likely(nodeid == -1)) {
> - addr = (void*)__get_free_pages(flags, cachep->gfporder);
> - if (!addr)
> - return NULL;
> - page = virt_to_page(addr);
> - } else {
> - page = alloc_pages_node(nodeid, flags, cachep->gfporder);
> - if (!page)
> - return NULL;
> - addr = page_address(page);
> - }
> +
> + page = alloc_pages_node(nodeid, flags, cachep->gfporder);
> + if (!page)
> + return NULL;
> + addr = page_address(page);
>
> i = (1 << cachep->gfporder);
> if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
> @@ -2065,7 +2059,7 @@
>
> if (unlikely(!ac->avail)) {
> int x;
> - x = cache_grow(cachep, flags, -1);
> + x = cache_grow(cachep, flags, numa_node_id());
>
> // cache_grow can reenable interrupts, then ac could change.
> ac = ac_data(cachep);
--
"Next the statesmen will invent cheap lies, putting the blame upon
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince
himself that the war is just, and will thank God for the better sleep
he enjoys after this process of grotesque self-deception." -- Mark Twain