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mm/page_owner: add NUMA node filter

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Add NUMA node filtering functionality to page_owner to allow filtering
pages by specific NUMA node(s).  This is useful for NUMA-aware memory
allocation analysis and debugging.

The filter supports flexible input formats:
- Single node: nid=0
- Multiple nodes: nid=0,2,3
- Node range: nid=0-3
- Mixed format: nid=0,2-4,7

Example usage:
  # Using the page_owner_filter tool (recommended)
  ./page_owner_filter -n 0-3
  ./page_owner_filter -m stack_handle -n 0,2-4,7

The implementation uses per-file-descriptor filter state stored in
file->private_data, allowing each opener to have independent filter
configuration.  It uses nodemask_t for efficient multi-node filtering and
nodelist_parse() for flexible input parsing.  Node validity is verified
using nodes_subset() to reject nodes without memory.

Link: https://lore.kernel.org/20260707115411.1714314-3-zhen.ni@easystack.cn
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
Tested-by: Zi Yan <ziy@nvidia.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zhen Ni 2026-07-07 19:54:09 +08:00 committed by Andrew Morton
parent 8570b65220
commit bed8003612
1 changed files with 52 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
mm/page_owner.c
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@ -68,6 +68,8 @@ static const char * const page_owner_print_mode_strings[] = {
struct page_owner_filter_state {
enum page_owner_print_mode print_mode;
nodemask_t nid_filter;
bool nid_filter_enabled;
};
static bool page_owner_enabled __initdata;
@ -803,6 +805,21 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
if (!handle)
goto ext_put_continue;
if (state->nid_filter_enabled) {
int nid;
memdesc_flags_t page_flags = READ_ONCE(page->flags);
/*
* Bypass PF_POISONED_CHECK() in page_to_nid() to avoid
* VM_BUG_ON when accessing poisoned pages.
*/
if (page_flags.f == PAGE_POISON_PATTERN)
goto ext_put_continue;
nid = memdesc_nid(page_flags);
if (!node_isset(nid, state->nid_filter))
goto ext_put_continue;
}
/* Record the next PFN to read in the file offset */
*ppos = pfn + 1;
@ -812,6 +829,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
&page_owner_tmp, handle, state);
ext_put_continue:
page_ext_put(page_ext);
cond_resched();
}
return 0;
@ -907,6 +925,8 @@ static int page_owner_open(struct inode *inode, struct file *file)
return -ENOMEM;
state->print_mode = PAGE_OWNER_PRINT_STACK;
nodes_clear(state->nid_filter);
state->nid_filter_enabled = false;
file->private_data = state;
return 0;
}
@ -927,12 +947,17 @@ static ssize_t page_owner_write(struct file *file,
int ret;
struct page_owner_filter_state *state = file->private_data;
enum page_owner_print_mode new_print_mode;
nodemask_t new_nid_filter;
bool new_nid_filter_enabled;
/*
* Maximum input length for filter commands:
* 32: print_mode command max length is 17 ("mode=stack_handle").
* - 32: print_mode command max length is 17 ("mode=stack_handle")
* with sufficient buffer
* - 6 * MAX_NUMNODES: worst case for nid list
* Worst case per node: ",NNNNN" (comma + 5-digit node number) = 6 bytes
*/
if (count > 32)
if (count > 32 + 6 * MAX_NUMNODES)
return -EINVAL;
kbuf = memdup_user_nul(buf, count);
@ -942,6 +967,8 @@ static ssize_t page_owner_write(struct file *file,
orig = kbuf;
new_print_mode = state->print_mode;
new_nid_filter = state->nid_filter;
new_nid_filter_enabled = state->nid_filter_enabled;
while ((token = strsep(&kbuf, " \t\n")) != NULL) {
if (*token == '\0')
@ -953,13 +980,36 @@ static ssize_t page_owner_write(struct file *file,
if (ret < 0)
goto out_free;
new_print_mode = ret;
} else if (!strncmp(token, "nid=", 4)) {
ret = nodelist_parse(token + 4, new_nid_filter);
if (ret < 0)
goto out_free;
if (nodes_empty(new_nid_filter)) {
ret = -EINVAL;
goto out_free;
}
/*
* We want to filter memory allocations by numa nodes, so make sure
* that the specified nodes have memory.
*/
if (!nodes_subset(new_nid_filter, node_states[N_MEMORY])) {
ret = -EINVAL;
goto out_free;
}
new_nid_filter_enabled = true;
} else {
ret = -EINVAL;
goto out_free;
}
}
/* Commit all filter changes */
state->print_mode = new_print_mode;
state->nid_filter = new_nid_filter;
state->nid_filter_enabled = new_nid_filter_enabled;
ret = count;