The patch titled
Subject: mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
has been added to the -mm mm-unstable branch. Its filename is
mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Barry Song <v-songbaohua@xxxxxxxx>
Subject: mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
Date: Sat, 3 Aug 2024 00:20:30 +1200
Patch series "mm: Ignite large folios swap-in support", v6.
Currently, we support mTHP swapout but not swapin. This means that once
mTHP is swapped out, it will come back as small folios when swapped in.
This is particularly detrimental for devices like Android, where more than
half of the memory is in swap.
The lack of mTHP swapin functionality makes mTHP a showstopper in
scenarios that heavily rely on swap. This patchset introduces mTHP
swap-in support. It starts with synchronous devices similar to zRAM,
aiming to benefit as many users as possible with minimal changes.
This patch (of 2):
With large folios swap-in, we might need to uncharge multiple entries all
together, add nr argument in mem_cgroup_swapin_uncharge_swap().
For the existing two users, just pass nr=1.
Link: https://lkml.kernel.org/r/20240802122031.117548-1-21cnbao@xxxxxxxxx
Link: https://lkml.kernel.org/r/20240802122031.117548-2-21cnbao@xxxxxxxxx
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Acked-by: Chris Li <chrisl@xxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Chuanhua Han <hanchuanhua@xxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Gao Xiang <xiang@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kairui Song <kasong@xxxxxxxxxxx>
Cc: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 5 +++--
mm/memcontrol.c | 7 ++++---
mm/memory.c | 2 +-
mm/swap_state.c | 2 +-
4 files changed, 9 insertions(+), 7 deletions(-)
--- a/include/linux/memcontrol.h~mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios
+++ a/include/linux/memcontrol.h
@@ -682,7 +682,8 @@ int mem_cgroup_hugetlb_try_charge(struct
int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
gfp_t gfp, swp_entry_t entry);
-void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry);
+
+void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
void __mem_cgroup_uncharge(struct folio *folio);
@@ -1181,7 +1182,7 @@ static inline int mem_cgroup_swapin_char
return 0;
}
-static inline void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
+static inline void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr)
{
}
--- a/mm/memcontrol.c~mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios
+++ a/mm/memcontrol.c
@@ -4590,14 +4590,15 @@ int mem_cgroup_swapin_charge_folio(struc
/*
* mem_cgroup_swapin_uncharge_swap - uncharge swap slot
- * @entry: swap entry for which the page is charged
+ * @entry: the first swap entry for which the pages are charged
+ * @nr_pages: number of pages which will be uncharged
*
* Call this function after successfully adding the charged page to swapcache.
*
* Note: This function assumes the page for which swap slot is being uncharged
* is order 0 page.
*/
-void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
+void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
{
/*
* Cgroup1's unified memory+swap counter has been charged with the
@@ -4617,7 +4618,7 @@ void mem_cgroup_swapin_uncharge_swap(swp
* let's not wait for it. The page already received a
* memory+swap charge, drop the swap entry duplicate.
*/
- mem_cgroup_uncharge_swap(entry, 1);
+ mem_cgroup_uncharge_swap(entry, nr_pages);
}
}
--- a/mm/memory.c~mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios
+++ a/mm/memory.c
@@ -4102,7 +4102,7 @@ vm_fault_t do_swap_page(struct vm_fault
ret = VM_FAULT_OOM;
goto out_page;
}
- mem_cgroup_swapin_uncharge_swap(entry);
+ mem_cgroup_swapin_uncharge_swap(entry, 1);
shadow = get_shadow_from_swap_cache(entry);
if (shadow)
--- a/mm/swap_state.c~mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios
+++ a/mm/swap_state.c
@@ -522,7 +522,7 @@ struct folio *__read_swap_cache_async(sw
if (add_to_swap_cache(new_folio, entry, gfp_mask & GFP_RECLAIM_MASK, &shadow))
goto fail_unlock;
- mem_cgroup_swapin_uncharge_swap(entry);
+ mem_cgroup_swapin_uncharge_swap(entry, 1);
if (shadow)
workingset_refault(new_folio, shadow);
_
Patches currently in -mm which might be from v-songbaohua@xxxxxxxx are
mm-extend-usage-parameter-so-that-cluster_swap_free_nr-can-be-reused.patch
mm-swap-add-nr-argument-in-swapcache_prepare-and-swapcache_clear-to-support-large-folios.patch
vpda-try-to-fix-the-potential-crash-due-to-misusing-__gfp_nofail.patch
mm-document-__gfp_nofail-must-be-blockable.patch
mm-bug_on-to-avoid-null-deference-while-__gfp_nofail-fails.patch
mm-prohibit-null-deference-exposed-for-unsupported-non-blockable-__gfp_nofail.patch
mm-add-nr-argument-in-mem_cgroup_swapin_uncharge_swap-helper-to-support-large-folios.patch
