mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 08:19:28 +00:00
![Tejun Heo](/assets/img/avatar_default.png)
percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
397 lines
10 KiB
C
397 lines
10 KiB
C
/*
|
|
* linux/mm/swap_state.c
|
|
*
|
|
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
|
|
* Swap reorganised 29.12.95, Stephen Tweedie
|
|
*
|
|
* Rewritten to use page cache, (C) 1998 Stephen Tweedie
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/init.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/pagevec.h>
|
|
#include <linux/migrate.h>
|
|
#include <linux/page_cgroup.h>
|
|
|
|
#include <asm/pgtable.h>
|
|
|
|
/*
|
|
* swapper_space is a fiction, retained to simplify the path through
|
|
* vmscan's shrink_page_list, to make sync_page look nicer, and to allow
|
|
* future use of radix_tree tags in the swap cache.
|
|
*/
|
|
static const struct address_space_operations swap_aops = {
|
|
.writepage = swap_writepage,
|
|
.sync_page = block_sync_page,
|
|
.set_page_dirty = __set_page_dirty_nobuffers,
|
|
.migratepage = migrate_page,
|
|
};
|
|
|
|
static struct backing_dev_info swap_backing_dev_info = {
|
|
.name = "swap",
|
|
.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
|
|
.unplug_io_fn = swap_unplug_io_fn,
|
|
};
|
|
|
|
struct address_space swapper_space = {
|
|
.page_tree = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
|
|
.tree_lock = __SPIN_LOCK_UNLOCKED(swapper_space.tree_lock),
|
|
.a_ops = &swap_aops,
|
|
.i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear),
|
|
.backing_dev_info = &swap_backing_dev_info,
|
|
};
|
|
|
|
#define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0)
|
|
|
|
static struct {
|
|
unsigned long add_total;
|
|
unsigned long del_total;
|
|
unsigned long find_success;
|
|
unsigned long find_total;
|
|
} swap_cache_info;
|
|
|
|
void show_swap_cache_info(void)
|
|
{
|
|
printk("%lu pages in swap cache\n", total_swapcache_pages);
|
|
printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu\n",
|
|
swap_cache_info.add_total, swap_cache_info.del_total,
|
|
swap_cache_info.find_success, swap_cache_info.find_total);
|
|
printk("Free swap = %ldkB\n", nr_swap_pages << (PAGE_SHIFT - 10));
|
|
printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10));
|
|
}
|
|
|
|
/*
|
|
* __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
|
|
* but sets SwapCache flag and private instead of mapping and index.
|
|
*/
|
|
static int __add_to_swap_cache(struct page *page, swp_entry_t entry)
|
|
{
|
|
int error;
|
|
|
|
VM_BUG_ON(!PageLocked(page));
|
|
VM_BUG_ON(PageSwapCache(page));
|
|
VM_BUG_ON(!PageSwapBacked(page));
|
|
|
|
page_cache_get(page);
|
|
SetPageSwapCache(page);
|
|
set_page_private(page, entry.val);
|
|
|
|
spin_lock_irq(&swapper_space.tree_lock);
|
|
error = radix_tree_insert(&swapper_space.page_tree, entry.val, page);
|
|
if (likely(!error)) {
|
|
total_swapcache_pages++;
|
|
__inc_zone_page_state(page, NR_FILE_PAGES);
|
|
INC_CACHE_INFO(add_total);
|
|
}
|
|
spin_unlock_irq(&swapper_space.tree_lock);
|
|
|
|
if (unlikely(error)) {
|
|
/*
|
|
* Only the context which have set SWAP_HAS_CACHE flag
|
|
* would call add_to_swap_cache().
|
|
* So add_to_swap_cache() doesn't returns -EEXIST.
|
|
*/
|
|
VM_BUG_ON(error == -EEXIST);
|
|
set_page_private(page, 0UL);
|
|
ClearPageSwapCache(page);
|
|
page_cache_release(page);
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
|
|
int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
|
|
{
|
|
int error;
|
|
|
|
error = radix_tree_preload(gfp_mask);
|
|
if (!error) {
|
|
error = __add_to_swap_cache(page, entry);
|
|
radix_tree_preload_end();
|
|
}
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* This must be called only on pages that have
|
|
* been verified to be in the swap cache.
|
|
*/
|
|
void __delete_from_swap_cache(struct page *page)
|
|
{
|
|
VM_BUG_ON(!PageLocked(page));
|
|
VM_BUG_ON(!PageSwapCache(page));
|
|
VM_BUG_ON(PageWriteback(page));
|
|
|
|
radix_tree_delete(&swapper_space.page_tree, page_private(page));
|
|
set_page_private(page, 0);
|
|
ClearPageSwapCache(page);
|
|
total_swapcache_pages--;
|
|
__dec_zone_page_state(page, NR_FILE_PAGES);
|
|
INC_CACHE_INFO(del_total);
|
|
}
|
|
|
|
/**
|
|
* add_to_swap - allocate swap space for a page
|
|
* @page: page we want to move to swap
|
|
*
|
|
* Allocate swap space for the page and add the page to the
|
|
* swap cache. Caller needs to hold the page lock.
|
|
*/
|
|
int add_to_swap(struct page *page)
|
|
{
|
|
swp_entry_t entry;
|
|
int err;
|
|
|
|
VM_BUG_ON(!PageLocked(page));
|
|
VM_BUG_ON(!PageUptodate(page));
|
|
|
|
entry = get_swap_page();
|
|
if (!entry.val)
|
|
return 0;
|
|
|
|
/*
|
|
* Radix-tree node allocations from PF_MEMALLOC contexts could
|
|
* completely exhaust the page allocator. __GFP_NOMEMALLOC
|
|
* stops emergency reserves from being allocated.
|
|
*
|
|
* TODO: this could cause a theoretical memory reclaim
|
|
* deadlock in the swap out path.
|
|
*/
|
|
/*
|
|
* Add it to the swap cache and mark it dirty
|
|
*/
|
|
err = add_to_swap_cache(page, entry,
|
|
__GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN);
|
|
|
|
if (!err) { /* Success */
|
|
SetPageDirty(page);
|
|
return 1;
|
|
} else { /* -ENOMEM radix-tree allocation failure */
|
|
/*
|
|
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
|
|
* clear SWAP_HAS_CACHE flag.
|
|
*/
|
|
swapcache_free(entry, NULL);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This must be called only on pages that have
|
|
* been verified to be in the swap cache and locked.
|
|
* It will never put the page into the free list,
|
|
* the caller has a reference on the page.
|
|
*/
|
|
void delete_from_swap_cache(struct page *page)
|
|
{
|
|
swp_entry_t entry;
|
|
|
|
entry.val = page_private(page);
|
|
|
|
spin_lock_irq(&swapper_space.tree_lock);
|
|
__delete_from_swap_cache(page);
|
|
spin_unlock_irq(&swapper_space.tree_lock);
|
|
|
|
swapcache_free(entry, page);
|
|
page_cache_release(page);
|
|
}
|
|
|
|
/*
|
|
* If we are the only user, then try to free up the swap cache.
|
|
*
|
|
* Its ok to check for PageSwapCache without the page lock
|
|
* here because we are going to recheck again inside
|
|
* try_to_free_swap() _with_ the lock.
|
|
* - Marcelo
|
|
*/
|
|
static inline void free_swap_cache(struct page *page)
|
|
{
|
|
if (PageSwapCache(page) && !page_mapped(page) && trylock_page(page)) {
|
|
try_to_free_swap(page);
|
|
unlock_page(page);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Perform a free_page(), also freeing any swap cache associated with
|
|
* this page if it is the last user of the page.
|
|
*/
|
|
void free_page_and_swap_cache(struct page *page)
|
|
{
|
|
free_swap_cache(page);
|
|
page_cache_release(page);
|
|
}
|
|
|
|
/*
|
|
* Passed an array of pages, drop them all from swapcache and then release
|
|
* them. They are removed from the LRU and freed if this is their last use.
|
|
*/
|
|
void free_pages_and_swap_cache(struct page **pages, int nr)
|
|
{
|
|
struct page **pagep = pages;
|
|
|
|
lru_add_drain();
|
|
while (nr) {
|
|
int todo = min(nr, PAGEVEC_SIZE);
|
|
int i;
|
|
|
|
for (i = 0; i < todo; i++)
|
|
free_swap_cache(pagep[i]);
|
|
release_pages(pagep, todo, 0);
|
|
pagep += todo;
|
|
nr -= todo;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Lookup a swap entry in the swap cache. A found page will be returned
|
|
* unlocked and with its refcount incremented - we rely on the kernel
|
|
* lock getting page table operations atomic even if we drop the page
|
|
* lock before returning.
|
|
*/
|
|
struct page * lookup_swap_cache(swp_entry_t entry)
|
|
{
|
|
struct page *page;
|
|
|
|
page = find_get_page(&swapper_space, entry.val);
|
|
|
|
if (page)
|
|
INC_CACHE_INFO(find_success);
|
|
|
|
INC_CACHE_INFO(find_total);
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* Locate a page of swap in physical memory, reserving swap cache space
|
|
* and reading the disk if it is not already cached.
|
|
* A failure return means that either the page allocation failed or that
|
|
* the swap entry is no longer in use.
|
|
*/
|
|
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
|
|
struct vm_area_struct *vma, unsigned long addr)
|
|
{
|
|
struct page *found_page, *new_page = NULL;
|
|
int err;
|
|
|
|
do {
|
|
/*
|
|
* First check the swap cache. Since this is normally
|
|
* called after lookup_swap_cache() failed, re-calling
|
|
* that would confuse statistics.
|
|
*/
|
|
found_page = find_get_page(&swapper_space, entry.val);
|
|
if (found_page)
|
|
break;
|
|
|
|
/*
|
|
* Get a new page to read into from swap.
|
|
*/
|
|
if (!new_page) {
|
|
new_page = alloc_page_vma(gfp_mask, vma, addr);
|
|
if (!new_page)
|
|
break; /* Out of memory */
|
|
}
|
|
|
|
/*
|
|
* call radix_tree_preload() while we can wait.
|
|
*/
|
|
err = radix_tree_preload(gfp_mask & GFP_KERNEL);
|
|
if (err)
|
|
break;
|
|
|
|
/*
|
|
* Swap entry may have been freed since our caller observed it.
|
|
*/
|
|
err = swapcache_prepare(entry);
|
|
if (err == -EEXIST) { /* seems racy */
|
|
radix_tree_preload_end();
|
|
continue;
|
|
}
|
|
if (err) { /* swp entry is obsolete ? */
|
|
radix_tree_preload_end();
|
|
break;
|
|
}
|
|
|
|
/* May fail (-ENOMEM) if radix-tree node allocation failed. */
|
|
__set_page_locked(new_page);
|
|
SetPageSwapBacked(new_page);
|
|
err = __add_to_swap_cache(new_page, entry);
|
|
if (likely(!err)) {
|
|
radix_tree_preload_end();
|
|
/*
|
|
* Initiate read into locked page and return.
|
|
*/
|
|
lru_cache_add_anon(new_page);
|
|
swap_readpage(new_page);
|
|
return new_page;
|
|
}
|
|
radix_tree_preload_end();
|
|
ClearPageSwapBacked(new_page);
|
|
__clear_page_locked(new_page);
|
|
/*
|
|
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
|
|
* clear SWAP_HAS_CACHE flag.
|
|
*/
|
|
swapcache_free(entry, NULL);
|
|
} while (err != -ENOMEM);
|
|
|
|
if (new_page)
|
|
page_cache_release(new_page);
|
|
return found_page;
|
|
}
|
|
|
|
/**
|
|
* swapin_readahead - swap in pages in hope we need them soon
|
|
* @entry: swap entry of this memory
|
|
* @gfp_mask: memory allocation flags
|
|
* @vma: user vma this address belongs to
|
|
* @addr: target address for mempolicy
|
|
*
|
|
* Returns the struct page for entry and addr, after queueing swapin.
|
|
*
|
|
* Primitive swap readahead code. We simply read an aligned block of
|
|
* (1 << page_cluster) entries in the swap area. This method is chosen
|
|
* because it doesn't cost us any seek time. We also make sure to queue
|
|
* the 'original' request together with the readahead ones...
|
|
*
|
|
* This has been extended to use the NUMA policies from the mm triggering
|
|
* the readahead.
|
|
*
|
|
* Caller must hold down_read on the vma->vm_mm if vma is not NULL.
|
|
*/
|
|
struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
|
|
struct vm_area_struct *vma, unsigned long addr)
|
|
{
|
|
int nr_pages;
|
|
struct page *page;
|
|
unsigned long offset;
|
|
unsigned long end_offset;
|
|
|
|
/*
|
|
* Get starting offset for readaround, and number of pages to read.
|
|
* Adjust starting address by readbehind (for NUMA interleave case)?
|
|
* No, it's very unlikely that swap layout would follow vma layout,
|
|
* more likely that neighbouring swap pages came from the same node:
|
|
* so use the same "addr" to choose the same node for each swap read.
|
|
*/
|
|
nr_pages = valid_swaphandles(entry, &offset);
|
|
for (end_offset = offset + nr_pages; offset < end_offset; offset++) {
|
|
/* Ok, do the async read-ahead now */
|
|
page = read_swap_cache_async(swp_entry(swp_type(entry), offset),
|
|
gfp_mask, vma, addr);
|
|
if (!page)
|
|
break;
|
|
page_cache_release(page);
|
|
}
|
|
lru_add_drain(); /* Push any new pages onto the LRU now */
|
|
return read_swap_cache_async(entry, gfp_mask, vma, addr);
|
|
}
|