mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Joonsoo Kim](/assets/img/avatar_default.png)
Many developers already know that field for reference count of the struct page is _count and atomic type. They would try to handle it directly and this could break the purpose of page reference count tracepoint. To prevent direct _count modification, this patch rename it to _refcount and add warning message on the code. After that, developer who need to handle reference count will find that field should not be accessed directly. [akpm@linux-foundation.org: fix comments, per Vlastimil] [akpm@linux-foundation.org: Documentation/vm/transhuge.txt too] [sfr@canb.auug.org.au: sync ethernet driver changes] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Sunil Goutham <sgoutham@cavium.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Manish Chopra <manish.chopra@qlogic.com> Cc: Yuval Mintz <yuval.mintz@qlogic.com> Cc: Tariq Toukan <tariqt@mellanox.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
303 lines
6.9 KiB
C
303 lines
6.9 KiB
C
#include <linux/bootmem.h>
|
|
#include <linux/compiler.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/init.h>
|
|
#include <linux/ksm.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mmzone.h>
|
|
#include <linux/huge_mm.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/memcontrol.h>
|
|
#include <linux/mmu_notifier.h>
|
|
#include <linux/page_idle.h>
|
|
#include <linux/kernel-page-flags.h>
|
|
#include <asm/uaccess.h>
|
|
#include "internal.h"
|
|
|
|
#define KPMSIZE sizeof(u64)
|
|
#define KPMMASK (KPMSIZE - 1)
|
|
#define KPMBITS (KPMSIZE * BITS_PER_BYTE)
|
|
|
|
/* /proc/kpagecount - an array exposing page counts
|
|
*
|
|
* Each entry is a u64 representing the corresponding
|
|
* physical page count.
|
|
*/
|
|
static ssize_t kpagecount_read(struct file *file, char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
u64 __user *out = (u64 __user *)buf;
|
|
struct page *ppage;
|
|
unsigned long src = *ppos;
|
|
unsigned long pfn;
|
|
ssize_t ret = 0;
|
|
u64 pcount;
|
|
|
|
pfn = src / KPMSIZE;
|
|
count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
|
|
if (src & KPMMASK || count & KPMMASK)
|
|
return -EINVAL;
|
|
|
|
while (count > 0) {
|
|
if (pfn_valid(pfn))
|
|
ppage = pfn_to_page(pfn);
|
|
else
|
|
ppage = NULL;
|
|
if (!ppage || PageSlab(ppage))
|
|
pcount = 0;
|
|
else
|
|
pcount = page_mapcount(ppage);
|
|
|
|
if (put_user(pcount, out)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
pfn++;
|
|
out++;
|
|
count -= KPMSIZE;
|
|
|
|
cond_resched();
|
|
}
|
|
|
|
*ppos += (char __user *)out - buf;
|
|
if (!ret)
|
|
ret = (char __user *)out - buf;
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations proc_kpagecount_operations = {
|
|
.llseek = mem_lseek,
|
|
.read = kpagecount_read,
|
|
};
|
|
|
|
/* /proc/kpageflags - an array exposing page flags
|
|
*
|
|
* Each entry is a u64 representing the corresponding
|
|
* physical page flags.
|
|
*/
|
|
|
|
static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
|
|
{
|
|
return ((kflags >> kbit) & 1) << ubit;
|
|
}
|
|
|
|
u64 stable_page_flags(struct page *page)
|
|
{
|
|
u64 k;
|
|
u64 u;
|
|
|
|
/*
|
|
* pseudo flag: KPF_NOPAGE
|
|
* it differentiates a memory hole from a page with no flags
|
|
*/
|
|
if (!page)
|
|
return 1 << KPF_NOPAGE;
|
|
|
|
k = page->flags;
|
|
u = 0;
|
|
|
|
/*
|
|
* pseudo flags for the well known (anonymous) memory mapped pages
|
|
*
|
|
* Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
|
|
* simple test in page_mapped() is not enough.
|
|
*/
|
|
if (!PageSlab(page) && page_mapped(page))
|
|
u |= 1 << KPF_MMAP;
|
|
if (PageAnon(page))
|
|
u |= 1 << KPF_ANON;
|
|
if (PageKsm(page))
|
|
u |= 1 << KPF_KSM;
|
|
|
|
/*
|
|
* compound pages: export both head/tail info
|
|
* they together define a compound page's start/end pos and order
|
|
*/
|
|
if (PageHead(page))
|
|
u |= 1 << KPF_COMPOUND_HEAD;
|
|
if (PageTail(page))
|
|
u |= 1 << KPF_COMPOUND_TAIL;
|
|
if (PageHuge(page))
|
|
u |= 1 << KPF_HUGE;
|
|
/*
|
|
* PageTransCompound can be true for non-huge compound pages (slab
|
|
* pages or pages allocated by drivers with __GFP_COMP) because it
|
|
* just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
|
|
* to make sure a given page is a thp, not a non-huge compound page.
|
|
*/
|
|
else if (PageTransCompound(page)) {
|
|
struct page *head = compound_head(page);
|
|
|
|
if (PageLRU(head) || PageAnon(head))
|
|
u |= 1 << KPF_THP;
|
|
else if (is_huge_zero_page(head)) {
|
|
u |= 1 << KPF_ZERO_PAGE;
|
|
u |= 1 << KPF_THP;
|
|
}
|
|
} else if (is_zero_pfn(page_to_pfn(page)))
|
|
u |= 1 << KPF_ZERO_PAGE;
|
|
|
|
|
|
/*
|
|
* Caveats on high order pages: page->_refcount will only be set
|
|
* -1 on the head page; SLUB/SLQB do the same for PG_slab;
|
|
* SLOB won't set PG_slab at all on compound pages.
|
|
*/
|
|
if (PageBuddy(page))
|
|
u |= 1 << KPF_BUDDY;
|
|
else if (page_count(page) == 0 && is_free_buddy_page(page))
|
|
u |= 1 << KPF_BUDDY;
|
|
|
|
if (PageBalloon(page))
|
|
u |= 1 << KPF_BALLOON;
|
|
|
|
if (page_is_idle(page))
|
|
u |= 1 << KPF_IDLE;
|
|
|
|
u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
|
|
|
|
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
|
|
if (PageTail(page) && PageSlab(compound_head(page)))
|
|
u |= 1 << KPF_SLAB;
|
|
|
|
u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
|
|
u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
|
|
u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
|
|
u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
|
|
|
|
u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
|
|
u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
|
|
u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
|
|
u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
|
|
|
|
u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache);
|
|
u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
|
|
|
|
u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
|
|
u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
|
|
|
|
#ifdef CONFIG_MEMORY_FAILURE
|
|
u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
|
|
#endif
|
|
|
|
#ifdef CONFIG_ARCH_USES_PG_UNCACHED
|
|
u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
|
|
#endif
|
|
|
|
u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
|
|
u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
|
|
u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
|
|
u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
|
|
u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
|
|
u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
|
|
|
|
return u;
|
|
};
|
|
|
|
static ssize_t kpageflags_read(struct file *file, char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
u64 __user *out = (u64 __user *)buf;
|
|
struct page *ppage;
|
|
unsigned long src = *ppos;
|
|
unsigned long pfn;
|
|
ssize_t ret = 0;
|
|
|
|
pfn = src / KPMSIZE;
|
|
count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
|
|
if (src & KPMMASK || count & KPMMASK)
|
|
return -EINVAL;
|
|
|
|
while (count > 0) {
|
|
if (pfn_valid(pfn))
|
|
ppage = pfn_to_page(pfn);
|
|
else
|
|
ppage = NULL;
|
|
|
|
if (put_user(stable_page_flags(ppage), out)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
pfn++;
|
|
out++;
|
|
count -= KPMSIZE;
|
|
|
|
cond_resched();
|
|
}
|
|
|
|
*ppos += (char __user *)out - buf;
|
|
if (!ret)
|
|
ret = (char __user *)out - buf;
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations proc_kpageflags_operations = {
|
|
.llseek = mem_lseek,
|
|
.read = kpageflags_read,
|
|
};
|
|
|
|
#ifdef CONFIG_MEMCG
|
|
static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
u64 __user *out = (u64 __user *)buf;
|
|
struct page *ppage;
|
|
unsigned long src = *ppos;
|
|
unsigned long pfn;
|
|
ssize_t ret = 0;
|
|
u64 ino;
|
|
|
|
pfn = src / KPMSIZE;
|
|
count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
|
|
if (src & KPMMASK || count & KPMMASK)
|
|
return -EINVAL;
|
|
|
|
while (count > 0) {
|
|
if (pfn_valid(pfn))
|
|
ppage = pfn_to_page(pfn);
|
|
else
|
|
ppage = NULL;
|
|
|
|
if (ppage)
|
|
ino = page_cgroup_ino(ppage);
|
|
else
|
|
ino = 0;
|
|
|
|
if (put_user(ino, out)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
pfn++;
|
|
out++;
|
|
count -= KPMSIZE;
|
|
|
|
cond_resched();
|
|
}
|
|
|
|
*ppos += (char __user *)out - buf;
|
|
if (!ret)
|
|
ret = (char __user *)out - buf;
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations proc_kpagecgroup_operations = {
|
|
.llseek = mem_lseek,
|
|
.read = kpagecgroup_read,
|
|
};
|
|
#endif /* CONFIG_MEMCG */
|
|
|
|
static int __init proc_page_init(void)
|
|
{
|
|
proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
|
|
proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
|
|
#ifdef CONFIG_MEMCG
|
|
proc_create("kpagecgroup", S_IRUSR, NULL, &proc_kpagecgroup_operations);
|
|
#endif
|
|
return 0;
|
|
}
|
|
fs_initcall(proc_page_init);
|