kevin/linux
1
Fork 0
Code

swap: turn get_swap_page() into folio_alloc_swap()

Browse Source 
This removes an assumption that a large folio is HPAGE_PMD_NR pages
in size.

Link: https://lkml.kernel.org/r/20220504182857.4013401-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-05-12 20:23:02 -07:00 committed by Andrew Morton
parent d33e4e1412
commit e2e3fdc7d4
6 changed files with 35 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
include/linux/swap.h
View File

@ -470,7 +470,7 @@ static inline long get_nr_swap_pages(void)
}
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(struct page *page);
swp_entry_t folio_alloc_swap(struct folio *folio);
extern void put_swap_page(struct page *page, swp_entry_t entry);
extern swp_entry_t get_swap_page_of_type(int);
extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
@ -583,7 +583,7 @@ static inline int try_to_free_swap(struct page *page)
return 0;
}
static inline swp_entry_t get_swap_page(struct page *page)
static inline swp_entry_t folio_alloc_swap(struct folio *folio)
{
swp_entry_t entry;
entry.val = 0;
@ -643,12 +643,13 @@ static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
#ifdef CONFIG_MEMCG_SWAP
void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry);
extern int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
static inline int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
static inline int mem_cgroup_try_charge_swap(struct folio *folio,
swp_entry_t entry)
{
if (mem_cgroup_disabled())
return 0;
return __mem_cgroup_try_charge_swap(page, entry);
return __mem_cgroup_try_charge_swap(folio, entry);
}
extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
@ -666,7 +667,7 @@ static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
{
}
static inline int mem_cgroup_try_charge_swap(struct page *page,
static inline int mem_cgroup_try_charge_swap(struct folio *folio,
swp_entry_t entry)
{
return 0;

16
mm/memcontrol.c
View File

@ -7162,17 +7162,17 @@ void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
}
/**
* __mem_cgroup_try_charge_swap - try charging swap space for a page
* @page: page being added to swap
* __mem_cgroup_try_charge_swap - try charging swap space for a folio
* @folio: folio being added to swap
* @entry: swap entry to charge
*
* Try to charge @page's memcg for the swap space at @entry.
* Try to charge @folio's memcg for the swap space at @entry.
*
* Returns 0 on success, -ENOMEM on failure.
*/
int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry)
{
unsigned int nr_pages = thp_nr_pages(page);
unsigned int nr_pages = folio_nr_pages(folio);
struct page_counter *counter;
struct mem_cgroup *memcg;
unsigned short oldid;
@ -7180,9 +7180,9 @@ int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return 0;
memcg = page_memcg(page);
memcg = folio_memcg(folio);
VM_WARN_ON_ONCE_PAGE(!memcg, page);
VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
if (!memcg)
return 0;
@ -7205,7 +7205,7 @@ int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
if (nr_pages > 1)
mem_cgroup_id_get_many(memcg, nr_pages - 1);
oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
VM_BUG_ON_PAGE(oldid, page);
VM_BUG_ON_FOLIO(oldid, folio);
mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
return 0;

3
mm/shmem.c
View File

@ -1313,6 +1313,7 @@ int shmem_unuse(unsigned int type)
*/
static int shmem_writepage(struct page *page, struct writeback_control *wbc)
{
struct folio *folio = page_folio(page);
struct shmem_inode_info *info;
struct address_space *mapping;
struct inode *inode;
@ -1386,7 +1387,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
SetPageUptodate(page);
}
swap = get_swap_page(page);
swap = folio_alloc_swap(folio);
if (!swap.val)
goto redirty;

14
mm/swap_slots.c
View File

@ -117,7 +117,7 @@ static int alloc_swap_slot_cache(unsigned int cpu)
/*
* Do allocation outside swap_slots_cache_mutex
* as kvzalloc could trigger reclaim and get_swap_page,
* as kvzalloc could trigger reclaim and folio_alloc_swap,
* which can lock swap_slots_cache_mutex.
*/
slots = kvcalloc(SWAP_SLOTS_CACHE_SIZE, sizeof(swp_entry_t),
@ -213,7 +213,7 @@ static void __drain_swap_slots_cache(unsigned int type)
* this function can be invoked in the cpu
* hot plug path:
* cpu_up -> lock cpu_hotplug -> cpu hotplug state callback
* -> memory allocation -> direct reclaim -> get_swap_page
* -> memory allocation -> direct reclaim -> folio_alloc_swap
* -> drain_swap_slots_cache
*
* Hence the loop over current online cpu below could miss cpu that
@ -301,16 +301,16 @@ direct_free:
return 0;
}
swp_entry_t get_swap_page(struct page *page)
swp_entry_t folio_alloc_swap(struct folio *folio)
{
swp_entry_t entry;
struct swap_slots_cache *cache;
entry.val = 0;
if (PageTransHuge(page)) {
if (folio_test_large(folio)) {
if (IS_ENABLED(CONFIG_THP_SWAP))
get_swap_pages(1, &entry, HPAGE_PMD_NR);
get_swap_pages(1, &entry, folio_nr_pages(folio));
goto out;
}
@ -344,8 +344,8 @@ repeat:
get_swap_pages(1, &entry, 1);
out:
if (mem_cgroup_try_charge_swap(page, entry)) {
put_swap_page(page, entry);
if (mem_cgroup_try_charge_swap(folio, entry)) {
put_swap_page(&folio->page, entry);
entry.val = 0;
}
return entry;

3
mm/swap_state.c
View File

@ -184,13 +184,14 @@ void __delete_from_swap_cache(struct page *page,
*/
int add_to_swap(struct page *page)
{
struct folio *folio = page_folio(page);
swp_entry_t entry;
int err;
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(!PageUptodate(page), page);
entry = get_swap_page(page);
entry = folio_alloc_swap(folio);
if (!entry.val)
return 0;

17
mm/swapfile.c
View File

@ -77,9 +77,9 @@ static PLIST_HEAD(swap_active_head);
/*
* all available (active, not full) swap_info_structs
* protected with swap_avail_lock, ordered by priority.
* This is used by get_swap_page() instead of swap_active_head
* This is used by folio_alloc_swap() instead of swap_active_head
* because swap_active_head includes all swap_info_structs,
* but get_swap_page() doesn't need to look at full ones.
* but folio_alloc_swap() doesn't need to look at full ones.
* This uses its own lock instead of swap_lock because when a
* swap_info_struct changes between not-full/full, it needs to
* add/remove itself to/from this list, but the swap_info_struct->lock
@ -2109,11 +2109,12 @@ retry:
* Under global memory pressure, swap entries can be reinserted back
* into process space after the mmlist loop above passes over them.
*
* Limit the number of retries? No: when mmget_not_zero() above fails,
* that mm is likely to be freeing swap from exit_mmap(), which proceeds
* at its own independent pace; and even shmem_writepage() could have
* been preempted after get_swap_page(), temporarily hiding that swap.
* It's easy and robust (though cpu-intensive) just to keep retrying.
* Limit the number of retries? No: when mmget_not_zero()
* above fails, that mm is likely to be freeing swap from
* exit_mmap(), which proceeds at its own independent pace;
* and even shmem_writepage() could have been preempted after
* folio_alloc_swap(), temporarily hiding that swap. It's easy
* and robust (though cpu-intensive) just to keep retrying.
*/
if (READ_ONCE(si->inuse_pages)) {
if (!signal_pending(current))
@ -2327,7 +2328,7 @@ static void _enable_swap_info(struct swap_info_struct *p)
* which on removal of any swap_info_struct with an auto-assigned
* (i.e. negative) priority increments the auto-assigned priority
* of any lower-priority swap_info_structs.
* swap_avail_head needs to be priority ordered for get_swap_page(),
* swap_avail_head needs to be priority ordered for folio_alloc_swap(),
* which allocates swap pages from the highest available priority
* swap_info_struct.
*/