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Message-ID: <20250725162258.1043176-3-usamaarif642@gmail.com>
Date: Fri, 25 Jul 2025 17:22:41 +0100
From: Usama Arif <usamaarif642@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
david@...hat.com,
linux-mm@...ck.org
Cc: linux-fsdevel@...r.kernel.org,
corbet@....net,
rppt@...nel.org,
surenb@...gle.com,
mhocko@...e.com,
hannes@...xchg.org,
baohua@...nel.org,
shakeel.butt@...ux.dev,
riel@...riel.com,
ziy@...dia.com,
laoar.shao@...il.com,
dev.jain@....com,
baolin.wang@...ux.alibaba.com,
npache@...hat.com,
lorenzo.stoakes@...cle.com,
Liam.Howlett@...cle.com,
ryan.roberts@....com,
vbabka@...e.cz,
jannh@...gle.com,
Arnd Bergmann <arnd@...db.de>,
sj@...nel.org,
linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org,
kernel-team@...a.com,
Usama Arif <usamaarif642@...il.com>
Subject: [PATCH 2/5] mm/huge_memory: convert "tva_flags" to "enum tva_type" for thp_vma_allowable_order*()
From: David Hildenbrand <david@...hat.com>
Describing the context through a type is much clearer, and good enough
for our case.
We have:
* smaps handling for showing "THPeligible"
* Pagefault handling
* khugepaged handling
* Forced collapse handling: primarily MADV_COLLAPSE, but one other odd case
Really, we want to ignore sysfs only when we are forcing a collapse
through MADV_COLLAPSE, otherwise we want to enforce.
With this change, we immediately know if we are in the forced collapse
case, which will be valuable next.
Signed-off-by: David Hildenbrand <david@...hat.com>
Acked-by: Usama Arif <usamaarif642@...il.com>
---
fs/proc/task_mmu.c | 4 ++--
include/linux/huge_mm.h | 30 ++++++++++++++++++------------
mm/huge_memory.c | 8 ++++----
mm/khugepaged.c | 18 +++++++++---------
mm/memory.c | 14 ++++++--------
5 files changed, 39 insertions(+), 35 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3d6d8a9f13fc..d440df7b3d59 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1293,8 +1293,8 @@ static int show_smap(struct seq_file *m, void *v)
__show_smap(m, &mss, false);
seq_printf(m, "THPeligible: %8u\n",
- !!thp_vma_allowable_orders(vma, vma->vm_flags,
- TVA_SMAPS | TVA_ENFORCE_SYSFS, THP_ORDERS_ALL));
+ !!thp_vma_allowable_orders(vma, vma->vm_flags, TVA_SMAPS,
+ THP_ORDERS_ALL));
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 71db243a002e..b0ff54eee81c 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -94,12 +94,15 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
#define THP_ORDERS_ALL \
(THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_SPECIAL | THP_ORDERS_ALL_FILE_DEFAULT)
-#define TVA_SMAPS (1 << 0) /* Will be used for procfs */
-#define TVA_IN_PF (1 << 1) /* Page fault handler */
-#define TVA_ENFORCE_SYSFS (1 << 2) /* Obey sysfs configuration */
+enum tva_type {
+ TVA_SMAPS, /* Exposing "THPeligible:" in smaps. */
+ TVA_PAGEFAULT, /* Serving a page fault. */
+ TVA_KHUGEPAGED, /* Khugepaged collapse. */
+ TVA_FORCED_COLLAPSE, /* Forced collapse (i.e., MADV_COLLAPSE). */
+};
-#define thp_vma_allowable_order(vma, vm_flags, tva_flags, order) \
- (!!thp_vma_allowable_orders(vma, vm_flags, tva_flags, BIT(order)))
+#define thp_vma_allowable_order(vma, vm_flags, type, order) \
+ (!!thp_vma_allowable_orders(vma, vm_flags, type, BIT(order)))
#define split_folio(f) split_folio_to_list(f, NULL)
@@ -264,14 +267,14 @@ static inline unsigned long thp_vma_suitable_orders(struct vm_area_struct *vma,
unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
vm_flags_t vm_flags,
- unsigned long tva_flags,
+ enum tva_type type,
unsigned long orders);
/**
* thp_vma_allowable_orders - determine hugepage orders that are allowed for vma
* @vma: the vm area to check
* @vm_flags: use these vm_flags instead of vma->vm_flags
- * @tva_flags: Which TVA flags to honour
+ * @type: TVA type
* @orders: bitfield of all orders to consider
*
* Calculates the intersection of the requested hugepage orders and the allowed
@@ -285,11 +288,14 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
static inline
unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma,
vm_flags_t vm_flags,
- unsigned long tva_flags,
+ enum tva_type type,
unsigned long orders)
{
- /* Optimization to check if required orders are enabled early. */
- if ((tva_flags & TVA_ENFORCE_SYSFS) && vma_is_anonymous(vma)) {
+ /*
+ * Optimization to check if required orders are enabled early. Only
+ * forced collapse ignores sysfs configs.
+ */
+ if (type != TVA_FORCED_COLLAPSE && vma_is_anonymous(vma)) {
unsigned long mask = READ_ONCE(huge_anon_orders_always);
if (vm_flags & VM_HUGEPAGE)
@@ -303,7 +309,7 @@ unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma,
return 0;
}
- return __thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders);
+ return __thp_vma_allowable_orders(vma, vm_flags, type, orders);
}
struct thpsize {
@@ -536,7 +542,7 @@ static inline unsigned long thp_vma_suitable_orders(struct vm_area_struct *vma,
static inline unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma,
vm_flags_t vm_flags,
- unsigned long tva_flags,
+ enum tva_type type,
unsigned long orders)
{
return 0;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2b4ea5a2ce7d..85252b468f80 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -99,12 +99,12 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
vm_flags_t vm_flags,
- unsigned long tva_flags,
+ enum tva_type type,
unsigned long orders)
{
- bool smaps = tva_flags & TVA_SMAPS;
- bool in_pf = tva_flags & TVA_IN_PF;
- bool enforce_sysfs = tva_flags & TVA_ENFORCE_SYSFS;
+ const bool smaps = type == TVA_SMAPS;
+ const bool in_pf = type == TVA_PAGEFAULT;
+ const bool enforce_sysfs = type != TVA_FORCED_COLLAPSE;
unsigned long supported_orders;
/* Check the intersection of requested and supported orders. */
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 2c9008246785..7a54b6f2a346 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -474,8 +474,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
{
if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
hugepage_pmd_enabled()) {
- if (thp_vma_allowable_order(vma, vm_flags, TVA_ENFORCE_SYSFS,
- PMD_ORDER))
+ if (thp_vma_allowable_order(vma, vm_flags, TVA_KHUGEPAGED, PMD_ORDER))
__khugepaged_enter(vma->vm_mm);
}
}
@@ -921,7 +920,8 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
struct collapse_control *cc)
{
struct vm_area_struct *vma;
- unsigned long tva_flags = cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0;
+ enum tva_type tva_type = cc->is_khugepaged ? TVA_KHUGEPAGED :
+ TVA_FORCED_COLLAPSE;
if (unlikely(hpage_collapse_test_exit_or_disable(mm)))
return SCAN_ANY_PROCESS;
@@ -932,7 +932,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
if (!thp_vma_suitable_order(vma, address, PMD_ORDER))
return SCAN_ADDRESS_RANGE;
- if (!thp_vma_allowable_order(vma, vma->vm_flags, tva_flags, PMD_ORDER))
+ if (!thp_vma_allowable_order(vma, vma->vm_flags, tva_type, PMD_ORDER))
return SCAN_VMA_CHECK;
/*
* Anon VMA expected, the address may be unmapped then
@@ -1532,9 +1532,10 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
* in the page cache with a single hugepage. If a mm were to fault-in
* this memory (mapped by a suitably aligned VMA), we'd get the hugepage
* and map it by a PMD, regardless of sysfs THP settings. As such, let's
- * analogously elide sysfs THP settings here.
+ * analogously elide sysfs THP settings here and pretend we are
+ * collapsing.
*/
- if (!thp_vma_allowable_order(vma, vma->vm_flags, 0, PMD_ORDER))
+ if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_FORCED_COLLAPSE, PMD_ORDER))
return SCAN_VMA_CHECK;
/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
@@ -2431,8 +2432,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
progress++;
break;
}
- if (!thp_vma_allowable_order(vma, vma->vm_flags,
- TVA_ENFORCE_SYSFS, PMD_ORDER)) {
+ if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) {
skip:
progress++;
continue;
@@ -2766,7 +2766,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start,
BUG_ON(vma->vm_start > start);
BUG_ON(vma->vm_end < end);
- if (!thp_vma_allowable_order(vma, vma->vm_flags, 0, PMD_ORDER))
+ if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_FORCED_COLLAPSE, PMD_ORDER))
return -EINVAL;
cc = kmalloc(sizeof(*cc), GFP_KERNEL);
diff --git a/mm/memory.c b/mm/memory.c
index 92fd18a5d8d1..be761753f240 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4369,8 +4369,8 @@ static struct folio *alloc_swap_folio(struct vm_fault *vmf)
* Get a list of all the (large) orders below PMD_ORDER that are enabled
* and suitable for swapping THP.
*/
- orders = thp_vma_allowable_orders(vma, vma->vm_flags,
- TVA_IN_PF | TVA_ENFORCE_SYSFS, BIT(PMD_ORDER) - 1);
+ orders = thp_vma_allowable_orders(vma, vma->vm_flags, TVA_PAGEFAULT,
+ BIT(PMD_ORDER) - 1);
orders = thp_vma_suitable_orders(vma, vmf->address, orders);
orders = thp_swap_suitable_orders(swp_offset(entry),
vmf->address, orders);
@@ -4917,8 +4917,8 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
* for this vma. Then filter out the orders that can't be allocated over
* the faulting address and still be fully contained in the vma.
*/
- orders = thp_vma_allowable_orders(vma, vma->vm_flags,
- TVA_IN_PF | TVA_ENFORCE_SYSFS, BIT(PMD_ORDER) - 1);
+ orders = thp_vma_allowable_orders(vma, vma->vm_flags, TVA_PAGEFAULT,
+ BIT(PMD_ORDER) - 1);
orders = thp_vma_suitable_orders(vma, vmf->address, orders);
if (!orders)
@@ -6108,8 +6108,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
return VM_FAULT_OOM;
retry_pud:
if (pud_none(*vmf.pud) &&
- thp_vma_allowable_order(vma, vm_flags,
- TVA_IN_PF | TVA_ENFORCE_SYSFS, PUD_ORDER)) {
+ thp_vma_allowable_order(vma, vm_flags, TVA_PAGEFAULT, PUD_ORDER)) {
ret = create_huge_pud(&vmf);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
@@ -6143,8 +6142,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
goto retry_pud;
if (pmd_none(*vmf.pmd) &&
- thp_vma_allowable_order(vma, vm_flags,
- TVA_IN_PF | TVA_ENFORCE_SYSFS, PMD_ORDER)) {
+ thp_vma_allowable_order(vma, vm_flags, TVA_PAGEFAULT, PMD_ORDER)) {
ret = create_huge_pmd(&vmf);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
--
2.47.3
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