The patch titled
Subject: mm: introduce generic_mmap_hint()
has been added to the -mm mm-unstable branch. Its filename is
mm-introduce-generic_mmap_hint.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-introduce-generic_mmap_hint.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: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Subject: mm: introduce generic_mmap_hint()
Date: Wed, 11 Dec 2024 15:27:39 -0800
Patch series "mm: Introduce arch_mmap_hint()", v2.
This series introduces arch_mmap_hint() to handle allocating VA space
for the hint address.
Patches 1-16 introduce this new helper and Patch 17 uses it to fix the
issue of mmap hint being ignored in some cases due to THP alignment [1]
[1] https://lore.kernel.org/r/20241118214650.3667577-1-kaleshsingh@xxxxxxxxxx/
This patch (of 16):
Consolidate the hint searches from both directions (topdown and bottomup)
into generic_mmap_hint().
No functional change is introduced.
Link: https://lkml.kernel.org/r/20241211232754.1583023-1-kaleshsingh@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20241211232754.1583023-2-kaleshsingh@xxxxxxxxxx
Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Breno Leitao <leitao@xxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jason Andryuk <jason.andryuk@xxxxxxx>
Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/sched/mm.h | 4 +
mm/mmap.c | 76 ++++++++++++++++++++++---------------
2 files changed, 50 insertions(+), 30 deletions(-)
--- a/include/linux/sched/mm.h~mm-introduce-generic_mmap_hint
+++ a/include/linux/sched/mm.h
@@ -201,6 +201,10 @@ unsigned long mm_get_unmapped_area_vmfla
unsigned long flags,
vm_flags_t vm_flags);
+unsigned long generic_mmap_hint(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags);
+
unsigned long
generic_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff,
--- a/mm/mmap.c~mm-introduce-generic_mmap_hint
+++ a/mm/mmap.c
@@ -620,6 +620,47 @@ unsigned long vm_unmapped_area(struct vm
return addr;
}
+/*
+ * Look up unmapped area at the requested hint addr
+ *
+ * NOTE: MAP_FIXED is also handled here since it's a special case of
+ * enforcing the hint address.
+ *
+ * Returns:
+ * ERR_VALUE: If the requested mapping is not valid
+ * 0: If there isn't a sufficiently large hole at the hint addr.
+ * addr: If sufficient VA space is available at the hint address;
+ * or MAP_FIXED was specified.
+ */
+unsigned long generic_mmap_hint(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma, *prev;
+ const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
+
+ /* requested length too big for entire address space */
+ if (len > mmap_end - mmap_min_addr)
+ return -ENOMEM;
+
+ if (flags & MAP_FIXED)
+ return addr;
+
+ if (!addr)
+ return 0;
+
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma_prev(mm, addr, &prev);
+ if (mmap_end - len >= addr && addr >= mmap_min_addr &&
+ (!vma || addr + len <= vm_start_gap(vma)) &&
+ (!prev || addr >= vm_end_gap(prev)))
+ return addr;
+
+ /* Fallback to VA space search */
+ return 0;
+}
+
/* Get an address range which is currently unmapped.
* For shmat() with addr=0.
*
@@ -637,25 +678,13 @@ generic_get_unmapped_area(struct file *f
unsigned long flags, vm_flags_t vm_flags)
{
struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma, *prev;
struct vm_unmapped_area_info info = {};
const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
- if (len > mmap_end - mmap_min_addr)
- return -ENOMEM;
-
- if (flags & MAP_FIXED)
+ addr = generic_mmap_hint(filp, addr, len, pgoff, flags);
+ if (addr)
return addr;
- if (addr) {
- addr = PAGE_ALIGN(addr);
- vma = find_vma_prev(mm, addr, &prev);
- if (mmap_end - len >= addr && addr >= mmap_min_addr &&
- (!vma || addr + len <= vm_start_gap(vma)) &&
- (!prev || addr >= vm_end_gap(prev)))
- return addr;
- }
-
info.length = len;
info.low_limit = mm->mmap_base;
info.high_limit = mmap_end;
@@ -685,27 +714,14 @@ generic_get_unmapped_area_topdown(struct
unsigned long len, unsigned long pgoff,
unsigned long flags, vm_flags_t vm_flags)
{
- struct vm_area_struct *vma, *prev;
struct mm_struct *mm = current->mm;
struct vm_unmapped_area_info info = {};
const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
- /* requested length too big for entire address space */
- if (len > mmap_end - mmap_min_addr)
- return -ENOMEM;
-
- if (flags & MAP_FIXED)
- return addr;
-
/* requesting a specific address */
- if (addr) {
- addr = PAGE_ALIGN(addr);
- vma = find_vma_prev(mm, addr, &prev);
- if (mmap_end - len >= addr && addr >= mmap_min_addr &&
- (!vma || addr + len <= vm_start_gap(vma)) &&
- (!prev || addr >= vm_end_gap(prev)))
- return addr;
- }
+ addr = generic_mmap_hint(filp, addr, len, pgoff, flags);
+ if (addr)
+ return addr;
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
_
Patches currently in -mm which might be from kaleshsingh@xxxxxxxxxx are
mm-introduce-generic_mmap_hint.patch
mm-x86-introduce-arch_mmap_hint.patch
mm-arm-introduce-arch_mmap_hint.patch
mm-alpha-introduce-arch_mmap_hint.patch
mm-arc-use-generic_mmap_hint.patch
mm-csky-introduce-arch_mmap_hint.patch
mm-loongarch-introduce-arch_mmap_hint.patch
mm-mips-introduce-arch_align_mmap_hint.patch
mm-parisc-introduce-arch_align_mmap_hint.patch
mm-s390-use-generic_mmap_hint.patch
mm-sh-introduce-arch_mmap_hint.patch
mm-sparc32-introduce-arch_mmap_hint.patch
mm-sparc64-introduce-arch_mmap_hint.patch
mm-xtensa-introduce-arch_mmap_hint.patch
mm-powerpc-introduce-arch_mmap_hint.patch
mm-respect-mmap-hint-before-thp-alignment-if-allocation-is-possible.patch
