mm-shmem-rename-mthp-shmem-counters.patch removed from -mm tree

merged mm-stable Andrew Morton 1 participant 1 message Jul 12, 2024 Stable branch

Share & tools

Andrew Morton

author tree notice Applied

2024-07-12 22:55 UTC #0 lore raw

The quilt patch titled
Subject: mm: shmem: rename mTHP shmem counters
has been removed from the -mm tree. Its filename was
mm-shmem-rename-mthp-shmem-counters.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Ryan Roberts <[email protected]>
Subject: mm: shmem: rename mTHP shmem counters
Date: Wed, 10 Jul 2024 10:55:01 +0100

The legacy PMD-sized THP counters at /proc/vmstat include thp_file_alloc, thp_file_fallback and thp_file_fallback_charge, which rather confusingly refer to shmem THP and do not include any other types of file pages. This is inconsistent since in most other places in the kernel, THP counters are explicitly separated for anon, shmem and file flavours. However, we are stuck with it since it constitutes a user ABI.

Recently, commit 66f44583f9b6 ("mm: shmem: add mTHP counters for anonymous shmem") added equivalent mTHP stats for shmem, keeping the same "file_" prefix in the names. But in future, we may want to add extra stats to cover actual file pages, at which point, it would all become very confusing.

So let's take the opportunity to rename these new counters "shmem_" before the change makes it upstream and the ABI becomes immutable. While we are at it, let's improve the documentation for the legacy counters to make it clear that they count shmem pages only.

Link https://lkml.kernel.org/r/[email protected] open here

Signed-off-by Ryan Roberts <[email protected]>

Reviewed-by Baolin Wang <[email protected]>

Reviewed-by Lance Yang <[email protected]>

Reviewed-by Zi Yan <[email protected]>

Reviewed-by Barry Song <[email protected]>

Acked-by David Hildenbrand <[email protected]>

Cc Daniel Gomez <[email protected]>

Cc Hugh Dickins <[email protected]>

Cc Jonathan Corbet <[email protected]>

Cc Matthew Wilcox (Oracle) <[email protected]>

Cc <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

---

 Documentation/admin-guide/mm/transhuge.rst |   29 ++++++++++---------
 include/linux/huge_mm.h                    |    6 +--
 mm/huge_memory.c                           |   12 +++----
 mm/shmem.c                                 |    8 ++---
 4 files changed, 29 insertions(+), 26 deletions(-)

Documentation/admin-guide/mm/transhuge.rst renamed from Documentation/admin-guide/mm/transhuge.rst~mm-shmem-rename-mthp-shmem-counters +16 ~~-13~~

@@ -412,20 +412,23 @@ thp_collapse_alloc_failed
 	the allocation.
 
 thp_file_alloc
-	is incremented every time a file huge page is successfully
-	allocated.
+	is incremented every time a shmem huge page is successfully
+	allocated (Note that despite being named after "file", the counter
+	measures only shmem).
 
 thp_file_fallback
-	is incremented if a file huge page is attempted to be allocated
-	but fails and instead falls back to using small pages.
+	is incremented if a shmem huge page is attempted to be allocated
+	but fails and instead falls back to using small pages. (Note that
+	despite being named after "file", the counter measures only shmem).
 
 thp_file_fallback_charge
-	is incremented if a file huge page cannot be charged and instead
+	is incremented if a shmem huge page cannot be charged and instead
 	falls back to using small pages even though the allocation was
-	successful.
+	successful. (Note that despite being named after "file", the
+	counter measures only shmem).
 
 thp_file_mapped
-	is incremented every time a file huge page is mapped into
+	is incremented every time a file or shmem huge page is mapped into
 	user address space.
 
 thp_split_page

@@ -496,16 +499,16 @@ swpout_fallback
 	Usually because failed to allocate some continuous swap space
 	for the huge page.
 
-file_alloc
-	is incremented every time a file huge page is successfully
+shmem_alloc
+	is incremented every time a shmem huge page is successfully
 	allocated.
 
-file_fallback
-	is incremented if a file huge page is attempted to be allocated
+shmem_fallback
+	is incremented if a shmem huge page is attempted to be allocated
 	but fails and instead falls back to using small pages.
 
-file_fallback_charge
-	is incremented if a file huge page cannot be charged and instead
+shmem_fallback_charge
+	is incremented if a shmem huge page cannot be charged and instead
 	falls back to using small pages even though the allocation was
 	successful.

include/linux/huge_mm.h renamed from include/linux/huge_mm.h~mm-shmem-rename-mthp-shmem-counters +3 -3

@@ -269,9 +269,9 @@ enum mthp_stat_item {
 	MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,
 	MTHP_STAT_SWPOUT,
 	MTHP_STAT_SWPOUT_FALLBACK,
-	MTHP_STAT_FILE_ALLOC,
-	MTHP_STAT_FILE_FALLBACK,
-	MTHP_STAT_FILE_FALLBACK_CHARGE,
+	MTHP_STAT_SHMEM_ALLOC,
+	MTHP_STAT_SHMEM_FALLBACK,
+	MTHP_STAT_SHMEM_FALLBACK_CHARGE,
 	MTHP_STAT_SPLIT,
 	MTHP_STAT_SPLIT_FAILED,
 	MTHP_STAT_SPLIT_DEFERRED,

mm/huge_memory.c renamed from mm/huge_memory.c~mm-shmem-rename-mthp-shmem-counters +6 -6

@@ -568,9 +568,9 @@ DEFINE_MTHP_STAT_ATTR(anon_fault_fallbac
 DEFINE_MTHP_STAT_ATTR(anon_fault_fallback_charge, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
 DEFINE_MTHP_STAT_ATTR(swpout, MTHP_STAT_SWPOUT);
 DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);
-DEFINE_MTHP_STAT_ATTR(file_alloc, MTHP_STAT_FILE_ALLOC);
-DEFINE_MTHP_STAT_ATTR(file_fallback, MTHP_STAT_FILE_FALLBACK);
-DEFINE_MTHP_STAT_ATTR(file_fallback_charge, MTHP_STAT_FILE_FALLBACK_CHARGE);
+DEFINE_MTHP_STAT_ATTR(shmem_alloc, MTHP_STAT_SHMEM_ALLOC);
+DEFINE_MTHP_STAT_ATTR(shmem_fallback, MTHP_STAT_SHMEM_FALLBACK);
+DEFINE_MTHP_STAT_ATTR(shmem_fallback_charge, MTHP_STAT_SHMEM_FALLBACK_CHARGE);
 DEFINE_MTHP_STAT_ATTR(split, MTHP_STAT_SPLIT);
 DEFINE_MTHP_STAT_ATTR(split_failed, MTHP_STAT_SPLIT_FAILED);
 DEFINE_MTHP_STAT_ATTR(split_deferred, MTHP_STAT_SPLIT_DEFERRED);

@@ -581,9 +581,9 @@ static struct attribute *stats_attrs[] =
 	&anon_fault_fallback_charge_attr.attr,
 	&swpout_attr.attr,
 	&swpout_fallback_attr.attr,
-	&file_alloc_attr.attr,
-	&file_fallback_attr.attr,
-	&file_fallback_charge_attr.attr,
+	&shmem_alloc_attr.attr,
+	&shmem_fallback_attr.attr,
+	&shmem_fallback_charge_attr.attr,
 	&split_attr.attr,
 	&split_failed_attr.attr,
 	&split_deferred_attr.attr,

mm/shmem.c renamed from mm/shmem.c~mm-shmem-rename-mthp-shmem-counters +4 -4

@@ -1777,7 +1777,7 @@ static struct folio *shmem_alloc_and_add
 			if (pages == HPAGE_PMD_NR)
 				count_vm_event(THP_FILE_FALLBACK);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-			count_mthp_stat(order, MTHP_STAT_FILE_FALLBACK);
+			count_mthp_stat(order, MTHP_STAT_SHMEM_FALLBACK);
 #endif
 			order = next_order(&suitable_orders, order);
 		}

@@ -1804,8 +1804,8 @@ allocated:
 				count_vm_event(THP_FILE_FALLBACK_CHARGE);
 			}
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-			count_mthp_stat(folio_order(folio), MTHP_STAT_FILE_FALLBACK);
-			count_mthp_stat(folio_order(folio), MTHP_STAT_FILE_FALLBACK_CHARGE);
+			count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_FALLBACK);
+			count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_FALLBACK_CHARGE);
 #endif
 		}
 		goto unlock;

@@ -2181,7 +2181,7 @@ repeat:
 			if (folio_test_pmd_mappable(folio))
 				count_vm_event(THP_FILE_ALLOC);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-			count_mthp_stat(folio_order(folio), MTHP_STAT_FILE_ALLOC);
+			count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_ALLOC);
 #endif
 			goto alloced;
 		}

Patches currently in -mm which might be from [email protected] are