Hi,
I have read some of these uses (of migrate_page) from linux kernel source code
and tried to use this function in my kernel module.
But it somehow hangs my module.
Linux version : 2.6 and system has 4 NUMA nodes (0-3) and has 16 cores in total.
I have done following: ( I already have a pointer to old page as pg ) [ this
code is somewhat taken from usage of migrate_page in mm/migrate.c file ]
struct page *new_page = alloc_pages_exact_node(2,GFP_HIGHUSER_MOVABLE |
GFP_THISNODE, 0);
if ( new_page != NULL )
{
if ( trylock_page(new_page) )
{
new_page-index = pg-index;
new_page-mapping = pg-mapping;
struct address_space *mapping = pg-mapping;
migrate_page(mapping, new_page, pg);
unlock_page(new_page);
}
}
- I have checked without locking also, but it does not work
- I check the existence of both pages and on what NUMA node they are assigned
and it gives me correct information. It is only when I make a call to
migrate_page does the code hangs.
Any ideas?
Ajay
From: valdis.kletni...@vt.edu valdis.kletni...@vt.edu
To: ajay saini ajay_saini1...@yahoo.co.in
Cc: kernelnewbies@kernelnewbies.org kernelnewbies@kernelnewbies.org
Sent: Sunday, 22 September 2013 9:53 PM
Subject: Re: working of migrate_page (exported) function in mm/migrate.c linux
Kernel
On Mon, 23 Sep 2013 09:00:21 +0800, ajay saini said:
Is it used somewhere ?
[~] cd /usr/src/linux-next/
[/usr/src/linux-next] find [a-z]* -name '*.[ch]' | xargs grep migrate_page |
grep -v migrate_pages
And start searching from there. You'll probably have to iterate several
times, because there's at least onea few lines of the form:
mm/swap_state.c: .migratepage = migrate_page,
mm/shmem.c: .migratepage = migrate_page,
which means you need to figure out who calls that function pointer.
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