mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Johannes Thumshirn](/assets/img/avatar_default.png)
The swap code only adds a single page to a newly created bio. So use __bio_add_page() to add the page which is guaranteed to succeed in this case. This brings us closer to marking bio_add_page() as __must_check. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/5bdafd9de806b2dab92302b30eb7a3a5f10c37d9.1685532726.git.johannes.thumshirn@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
546 lines
13 KiB
C
546 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* linux/mm/page_io.c
|
|
*
|
|
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
|
|
*
|
|
* Swap reorganised 29.12.95,
|
|
* Asynchronous swapping added 30.12.95. Stephen Tweedie
|
|
* Removed race in async swapping. 14.4.1996. Bruno Haible
|
|
* Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
|
|
* Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/frontswap.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/psi.h>
|
|
#include <linux/uio.h>
|
|
#include <linux/sched/task.h>
|
|
#include <linux/delayacct.h>
|
|
#include "swap.h"
|
|
|
|
static void __end_swap_bio_write(struct bio *bio)
|
|
{
|
|
struct page *page = bio_first_page_all(bio);
|
|
|
|
if (bio->bi_status) {
|
|
SetPageError(page);
|
|
/*
|
|
* We failed to write the page out to swap-space.
|
|
* Re-dirty the page in order to avoid it being reclaimed.
|
|
* Also print a dire warning that things will go BAD (tm)
|
|
* very quickly.
|
|
*
|
|
* Also clear PG_reclaim to avoid folio_rotate_reclaimable()
|
|
*/
|
|
set_page_dirty(page);
|
|
pr_alert_ratelimited("Write-error on swap-device (%u:%u:%llu)\n",
|
|
MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
|
|
(unsigned long long)bio->bi_iter.bi_sector);
|
|
ClearPageReclaim(page);
|
|
}
|
|
end_page_writeback(page);
|
|
}
|
|
|
|
static void end_swap_bio_write(struct bio *bio)
|
|
{
|
|
__end_swap_bio_write(bio);
|
|
bio_put(bio);
|
|
}
|
|
|
|
static void __end_swap_bio_read(struct bio *bio)
|
|
{
|
|
struct page *page = bio_first_page_all(bio);
|
|
|
|
if (bio->bi_status) {
|
|
SetPageError(page);
|
|
ClearPageUptodate(page);
|
|
pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
|
|
MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
|
|
(unsigned long long)bio->bi_iter.bi_sector);
|
|
} else {
|
|
SetPageUptodate(page);
|
|
}
|
|
unlock_page(page);
|
|
}
|
|
|
|
static void end_swap_bio_read(struct bio *bio)
|
|
{
|
|
__end_swap_bio_read(bio);
|
|
bio_put(bio);
|
|
}
|
|
|
|
int generic_swapfile_activate(struct swap_info_struct *sis,
|
|
struct file *swap_file,
|
|
sector_t *span)
|
|
{
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
unsigned blocks_per_page;
|
|
unsigned long page_no;
|
|
unsigned blkbits;
|
|
sector_t probe_block;
|
|
sector_t last_block;
|
|
sector_t lowest_block = -1;
|
|
sector_t highest_block = 0;
|
|
int nr_extents = 0;
|
|
int ret;
|
|
|
|
blkbits = inode->i_blkbits;
|
|
blocks_per_page = PAGE_SIZE >> blkbits;
|
|
|
|
/*
|
|
* Map all the blocks into the extent tree. This code doesn't try
|
|
* to be very smart.
|
|
*/
|
|
probe_block = 0;
|
|
page_no = 0;
|
|
last_block = i_size_read(inode) >> blkbits;
|
|
while ((probe_block + blocks_per_page) <= last_block &&
|
|
page_no < sis->max) {
|
|
unsigned block_in_page;
|
|
sector_t first_block;
|
|
|
|
cond_resched();
|
|
|
|
first_block = probe_block;
|
|
ret = bmap(inode, &first_block);
|
|
if (ret || !first_block)
|
|
goto bad_bmap;
|
|
|
|
/*
|
|
* It must be PAGE_SIZE aligned on-disk
|
|
*/
|
|
if (first_block & (blocks_per_page - 1)) {
|
|
probe_block++;
|
|
goto reprobe;
|
|
}
|
|
|
|
for (block_in_page = 1; block_in_page < blocks_per_page;
|
|
block_in_page++) {
|
|
sector_t block;
|
|
|
|
block = probe_block + block_in_page;
|
|
ret = bmap(inode, &block);
|
|
if (ret || !block)
|
|
goto bad_bmap;
|
|
|
|
if (block != first_block + block_in_page) {
|
|
/* Discontiguity */
|
|
probe_block++;
|
|
goto reprobe;
|
|
}
|
|
}
|
|
|
|
first_block >>= (PAGE_SHIFT - blkbits);
|
|
if (page_no) { /* exclude the header page */
|
|
if (first_block < lowest_block)
|
|
lowest_block = first_block;
|
|
if (first_block > highest_block)
|
|
highest_block = first_block;
|
|
}
|
|
|
|
/*
|
|
* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
|
|
*/
|
|
ret = add_swap_extent(sis, page_no, 1, first_block);
|
|
if (ret < 0)
|
|
goto out;
|
|
nr_extents += ret;
|
|
page_no++;
|
|
probe_block += blocks_per_page;
|
|
reprobe:
|
|
continue;
|
|
}
|
|
ret = nr_extents;
|
|
*span = 1 + highest_block - lowest_block;
|
|
if (page_no == 0)
|
|
page_no = 1; /* force Empty message */
|
|
sis->max = page_no;
|
|
sis->pages = page_no - 1;
|
|
sis->highest_bit = page_no - 1;
|
|
out:
|
|
return ret;
|
|
bad_bmap:
|
|
pr_err("swapon: swapfile has holes\n");
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* We may have stale swap cache pages in memory: notice
|
|
* them here and get rid of the unnecessary final write.
|
|
*/
|
|
int swap_writepage(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
struct folio *folio = page_folio(page);
|
|
int ret;
|
|
|
|
if (folio_free_swap(folio)) {
|
|
folio_unlock(folio);
|
|
return 0;
|
|
}
|
|
/*
|
|
* Arch code may have to preserve more data than just the page
|
|
* contents, e.g. memory tags.
|
|
*/
|
|
ret = arch_prepare_to_swap(&folio->page);
|
|
if (ret) {
|
|
folio_mark_dirty(folio);
|
|
folio_unlock(folio);
|
|
return ret;
|
|
}
|
|
if (frontswap_store(&folio->page) == 0) {
|
|
folio_start_writeback(folio);
|
|
folio_unlock(folio);
|
|
folio_end_writeback(folio);
|
|
return 0;
|
|
}
|
|
__swap_writepage(&folio->page, wbc);
|
|
return 0;
|
|
}
|
|
|
|
static inline void count_swpout_vm_event(struct page *page)
|
|
{
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
if (unlikely(PageTransHuge(page)))
|
|
count_vm_event(THP_SWPOUT);
|
|
#endif
|
|
count_vm_events(PSWPOUT, thp_nr_pages(page));
|
|
}
|
|
|
|
#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
|
|
static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
struct mem_cgroup *memcg;
|
|
|
|
memcg = page_memcg(page);
|
|
if (!memcg)
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys);
|
|
bio_associate_blkg_from_css(bio, css);
|
|
rcu_read_unlock();
|
|
}
|
|
#else
|
|
#define bio_associate_blkg_from_page(bio, page) do { } while (0)
|
|
#endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */
|
|
|
|
struct swap_iocb {
|
|
struct kiocb iocb;
|
|
struct bio_vec bvec[SWAP_CLUSTER_MAX];
|
|
int pages;
|
|
int len;
|
|
};
|
|
static mempool_t *sio_pool;
|
|
|
|
int sio_pool_init(void)
|
|
{
|
|
if (!sio_pool) {
|
|
mempool_t *pool = mempool_create_kmalloc_pool(
|
|
SWAP_CLUSTER_MAX, sizeof(struct swap_iocb));
|
|
if (cmpxchg(&sio_pool, NULL, pool))
|
|
mempool_destroy(pool);
|
|
}
|
|
if (!sio_pool)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
static void sio_write_complete(struct kiocb *iocb, long ret)
|
|
{
|
|
struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
|
|
struct page *page = sio->bvec[0].bv_page;
|
|
int p;
|
|
|
|
if (ret != sio->len) {
|
|
/*
|
|
* In the case of swap-over-nfs, this can be a
|
|
* temporary failure if the system has limited
|
|
* memory for allocating transmit buffers.
|
|
* Mark the page dirty and avoid
|
|
* folio_rotate_reclaimable but rate-limit the
|
|
* messages but do not flag PageError like
|
|
* the normal direct-to-bio case as it could
|
|
* be temporary.
|
|
*/
|
|
pr_err_ratelimited("Write error %ld on dio swapfile (%llu)\n",
|
|
ret, page_file_offset(page));
|
|
for (p = 0; p < sio->pages; p++) {
|
|
page = sio->bvec[p].bv_page;
|
|
set_page_dirty(page);
|
|
ClearPageReclaim(page);
|
|
}
|
|
} else {
|
|
for (p = 0; p < sio->pages; p++)
|
|
count_swpout_vm_event(sio->bvec[p].bv_page);
|
|
}
|
|
|
|
for (p = 0; p < sio->pages; p++)
|
|
end_page_writeback(sio->bvec[p].bv_page);
|
|
|
|
mempool_free(sio, sio_pool);
|
|
}
|
|
|
|
static void swap_writepage_fs(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
struct swap_iocb *sio = NULL;
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
struct file *swap_file = sis->swap_file;
|
|
loff_t pos = page_file_offset(page);
|
|
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
if (wbc->swap_plug)
|
|
sio = *wbc->swap_plug;
|
|
if (sio) {
|
|
if (sio->iocb.ki_filp != swap_file ||
|
|
sio->iocb.ki_pos + sio->len != pos) {
|
|
swap_write_unplug(sio);
|
|
sio = NULL;
|
|
}
|
|
}
|
|
if (!sio) {
|
|
sio = mempool_alloc(sio_pool, GFP_NOIO);
|
|
init_sync_kiocb(&sio->iocb, swap_file);
|
|
sio->iocb.ki_complete = sio_write_complete;
|
|
sio->iocb.ki_pos = pos;
|
|
sio->pages = 0;
|
|
sio->len = 0;
|
|
}
|
|
bvec_set_page(&sio->bvec[sio->pages], page, thp_size(page), 0);
|
|
sio->len += thp_size(page);
|
|
sio->pages += 1;
|
|
if (sio->pages == ARRAY_SIZE(sio->bvec) || !wbc->swap_plug) {
|
|
swap_write_unplug(sio);
|
|
sio = NULL;
|
|
}
|
|
if (wbc->swap_plug)
|
|
*wbc->swap_plug = sio;
|
|
}
|
|
|
|
static void swap_writepage_bdev_sync(struct page *page,
|
|
struct writeback_control *wbc, struct swap_info_struct *sis)
|
|
{
|
|
struct bio_vec bv;
|
|
struct bio bio;
|
|
|
|
bio_init(&bio, sis->bdev, &bv, 1,
|
|
REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc));
|
|
bio.bi_iter.bi_sector = swap_page_sector(page);
|
|
__bio_add_page(&bio, page, thp_size(page), 0);
|
|
|
|
bio_associate_blkg_from_page(&bio, page);
|
|
count_swpout_vm_event(page);
|
|
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
|
|
submit_bio_wait(&bio);
|
|
__end_swap_bio_write(&bio);
|
|
}
|
|
|
|
static void swap_writepage_bdev_async(struct page *page,
|
|
struct writeback_control *wbc, struct swap_info_struct *sis)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc(sis->bdev, 1,
|
|
REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
|
|
GFP_NOIO);
|
|
bio->bi_iter.bi_sector = swap_page_sector(page);
|
|
bio->bi_end_io = end_swap_bio_write;
|
|
__bio_add_page(bio, page, thp_size(page), 0);
|
|
|
|
bio_associate_blkg_from_page(bio, page);
|
|
count_swpout_vm_event(page);
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
submit_bio(bio);
|
|
}
|
|
|
|
void __swap_writepage(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
VM_BUG_ON_PAGE(!PageSwapCache(page), page);
|
|
/*
|
|
* ->flags can be updated non-atomicially (scan_swap_map_slots),
|
|
* but that will never affect SWP_FS_OPS, so the data_race
|
|
* is safe.
|
|
*/
|
|
if (data_race(sis->flags & SWP_FS_OPS))
|
|
swap_writepage_fs(page, wbc);
|
|
else if (sis->flags & SWP_SYNCHRONOUS_IO)
|
|
swap_writepage_bdev_sync(page, wbc, sis);
|
|
else
|
|
swap_writepage_bdev_async(page, wbc, sis);
|
|
}
|
|
|
|
void swap_write_unplug(struct swap_iocb *sio)
|
|
{
|
|
struct iov_iter from;
|
|
struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
|
|
int ret;
|
|
|
|
iov_iter_bvec(&from, ITER_SOURCE, sio->bvec, sio->pages, sio->len);
|
|
ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
|
|
if (ret != -EIOCBQUEUED)
|
|
sio_write_complete(&sio->iocb, ret);
|
|
}
|
|
|
|
static void sio_read_complete(struct kiocb *iocb, long ret)
|
|
{
|
|
struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
|
|
int p;
|
|
|
|
if (ret == sio->len) {
|
|
for (p = 0; p < sio->pages; p++) {
|
|
struct page *page = sio->bvec[p].bv_page;
|
|
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
}
|
|
count_vm_events(PSWPIN, sio->pages);
|
|
} else {
|
|
for (p = 0; p < sio->pages; p++) {
|
|
struct page *page = sio->bvec[p].bv_page;
|
|
|
|
SetPageError(page);
|
|
ClearPageUptodate(page);
|
|
unlock_page(page);
|
|
}
|
|
pr_alert_ratelimited("Read-error on swap-device\n");
|
|
}
|
|
mempool_free(sio, sio_pool);
|
|
}
|
|
|
|
static void swap_readpage_fs(struct page *page,
|
|
struct swap_iocb **plug)
|
|
{
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
struct swap_iocb *sio = NULL;
|
|
loff_t pos = page_file_offset(page);
|
|
|
|
if (plug)
|
|
sio = *plug;
|
|
if (sio) {
|
|
if (sio->iocb.ki_filp != sis->swap_file ||
|
|
sio->iocb.ki_pos + sio->len != pos) {
|
|
swap_read_unplug(sio);
|
|
sio = NULL;
|
|
}
|
|
}
|
|
if (!sio) {
|
|
sio = mempool_alloc(sio_pool, GFP_KERNEL);
|
|
init_sync_kiocb(&sio->iocb, sis->swap_file);
|
|
sio->iocb.ki_pos = pos;
|
|
sio->iocb.ki_complete = sio_read_complete;
|
|
sio->pages = 0;
|
|
sio->len = 0;
|
|
}
|
|
bvec_set_page(&sio->bvec[sio->pages], page, thp_size(page), 0);
|
|
sio->len += thp_size(page);
|
|
sio->pages += 1;
|
|
if (sio->pages == ARRAY_SIZE(sio->bvec) || !plug) {
|
|
swap_read_unplug(sio);
|
|
sio = NULL;
|
|
}
|
|
if (plug)
|
|
*plug = sio;
|
|
}
|
|
|
|
static void swap_readpage_bdev_sync(struct page *page,
|
|
struct swap_info_struct *sis)
|
|
{
|
|
struct bio_vec bv;
|
|
struct bio bio;
|
|
|
|
bio_init(&bio, sis->bdev, &bv, 1, REQ_OP_READ);
|
|
bio.bi_iter.bi_sector = swap_page_sector(page);
|
|
__bio_add_page(&bio, page, thp_size(page), 0);
|
|
/*
|
|
* Keep this task valid during swap readpage because the oom killer may
|
|
* attempt to access it in the page fault retry time check.
|
|
*/
|
|
get_task_struct(current);
|
|
count_vm_event(PSWPIN);
|
|
submit_bio_wait(&bio);
|
|
__end_swap_bio_read(&bio);
|
|
put_task_struct(current);
|
|
}
|
|
|
|
static void swap_readpage_bdev_async(struct page *page,
|
|
struct swap_info_struct *sis)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
|
|
bio->bi_iter.bi_sector = swap_page_sector(page);
|
|
bio->bi_end_io = end_swap_bio_read;
|
|
__bio_add_page(bio, page, thp_size(page), 0);
|
|
count_vm_event(PSWPIN);
|
|
submit_bio(bio);
|
|
}
|
|
|
|
void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
|
|
{
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
bool workingset = PageWorkingset(page);
|
|
unsigned long pflags;
|
|
bool in_thrashing;
|
|
|
|
VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
|
|
VM_BUG_ON_PAGE(!PageLocked(page), page);
|
|
VM_BUG_ON_PAGE(PageUptodate(page), page);
|
|
|
|
/*
|
|
* Count submission time as memory stall and delay. When the device
|
|
* is congested, or the submitting cgroup IO-throttled, submission
|
|
* can be a significant part of overall IO time.
|
|
*/
|
|
if (workingset) {
|
|
delayacct_thrashing_start(&in_thrashing);
|
|
psi_memstall_enter(&pflags);
|
|
}
|
|
delayacct_swapin_start();
|
|
|
|
if (frontswap_load(page) == 0) {
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
} else if (data_race(sis->flags & SWP_FS_OPS)) {
|
|
swap_readpage_fs(page, plug);
|
|
} else if (synchronous || (sis->flags & SWP_SYNCHRONOUS_IO)) {
|
|
swap_readpage_bdev_sync(page, sis);
|
|
} else {
|
|
swap_readpage_bdev_async(page, sis);
|
|
}
|
|
|
|
if (workingset) {
|
|
delayacct_thrashing_end(&in_thrashing);
|
|
psi_memstall_leave(&pflags);
|
|
}
|
|
delayacct_swapin_end();
|
|
}
|
|
|
|
void __swap_read_unplug(struct swap_iocb *sio)
|
|
{
|
|
struct iov_iter from;
|
|
struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
|
|
int ret;
|
|
|
|
iov_iter_bvec(&from, ITER_DEST, sio->bvec, sio->pages, sio->len);
|
|
ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
|
|
if (ret != -EIOCBQUEUED)
|
|
sio_read_complete(&sio->iocb, ret);
|
|
}
|