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641db40f3a
788 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Matthew Wilcox (Oracle)
|
1fec6890bf |
mm: remove references to pagevec
Most of these should just refer to the LRU cache rather than the data structure used to implement the LRU cache. Link: https://lkml.kernel.org/r/20230621164557.3510324-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Ryan Roberts
|
c33c794828 |
mm: ptep_get() conversion
Convert all instances of direct pte_t* dereferencing to instead use ptep_get() helper. This means that by default, the accesses change from a C dereference to a READ_ONCE(). This is technically the correct thing to do since where pgtables are modified by HW (for access/dirty) they are volatile and therefore we should always ensure READ_ONCE() semantics. But more importantly, by always using the helper, it can be overridden by the architecture to fully encapsulate the contents of the pte. Arch code is deliberately not converted, as the arch code knows best. It is intended that arch code (arm64) will override the default with its own implementation that can (e.g.) hide certain bits from the core code, or determine young/dirty status by mixing in state from another source. Conversion was done using Coccinelle: ---- // $ make coccicheck \ // COCCI=ptepget.cocci \ // SPFLAGS="--include-headers" \ // MODE=patch virtual patch @ depends on patch @ pte_t *v; @@ - *v + ptep_get(v) ---- Then reviewed and hand-edited to avoid multiple unnecessary calls to ptep_get(), instead opting to store the result of a single call in a variable, where it is correct to do so. This aims to negate any cost of READ_ONCE() and will benefit arch-overrides that may be more complex. Included is a fix for an issue in an earlier version of this patch that was pointed out by kernel test robot. The issue arose because config MMU=n elides definition of the ptep helper functions, including ptep_get(). HUGETLB_PAGE=n configs still define a simple huge_ptep_clear_flush() for linking purposes, which dereferences the ptep. So when both configs are disabled, this caused a build error because ptep_get() is not defined. Fix by continuing to do a direct dereference when MMU=n. This is safe because for this config the arch code cannot be trying to virtualize the ptes because none of the ptep helpers are defined. Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/ Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Sidhartha Kumar
|
b95826c9aa |
mm: remove set_compound_page_dtor()
All users can use the folio equivalent so this function can be safely removed. Link: https://lkml.kernel.org/r/20230612163405.99345-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tarun Sahu <tsahu@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hugh Dickins
|
c9c1ee20ee |
mm/huge_memory: split huge pmd under one pte_offset_map()
__split_huge_zero_page_pmd() use a single pte_offset_map() to sweep the extent: it's already under pmd_lock(), so this is no worse for latency; and since it's supposed to have full control of the just-withdrawn page table, here choose to VM_BUG_ON if it were to fail. And please don't increment haddr by PAGE_SIZE, that should remain huge aligned: declare a separate addr (not a bugfix, but it was deceptive). __split_huge_pmd_locked() likewise (but it had declared a separate addr); and change its BUG_ON(!pte_none) to VM_BUG_ON, for consistency with zero (those deposited page tables are sometimes victims of random corruption). Link: https://lkml.kernel.org/r/90cbed7f-90d9-b779-4a46-d2485baf9595@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hugh Dickins
|
a5be621ee2 |
mm/mremap: retry if either pte_offset_map_*lock() fails
move_ptes() return -EAGAIN if pte_offset_map_lock() of old fails, or if pte_offset_map_nolock() of new fails: move_page_tables() retry if so. But that does need a pmd_none() check inside, to stop endless loop when huge shmem is truncated (thank you to syzbot); and move_huge_pmd() must tolerate that a page table might have been allocated there just before (of course it would be more satisfying to remove the empty page table, but this is not a path worth optimizing). Link: https://lkml.kernel.org/r/65e5e84a-f04-947-23f2-b97d3462e1e@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yin Fengwei
|
deedad80f6 |
THP: avoid lock when check whether THP is in deferred list
free_transhuge_page() acquires split queue lock then check whether the THP
was added to deferred list or not. It brings high deferred queue lock
contention.
It's safe to check whether the THP is in deferred list or not without
holding the deferred queue lock in free_transhuge_page() because when code
hit free_transhuge_page(), there is no one tries to add the folio to
_deferred_list.
Running page_fault1 of will-it-scale + order 2 folio for anonymous
mapping with 96 processes on an Ice Lake 48C/96T test box, we could
see the 61% split_queue_lock contention:
- 63.02% 0.01% page_fault1_pro [kernel.kallsyms] [k] free_transhuge_page
- 63.01% free_transhuge_page
+ 62.91% _raw_spin_lock_irqsave
With this patch applied, the split_queue_lock contention is less
than 1%.
Link: https://lkml.kernel.org/r/20230429082759.1600796-2-fengwei.yin@intel.com
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
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David Hildenbrand
|
f3ebdf042d |
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
Staring at the comment "Recheck VMA as permissions can change since
migration started" in remove_migration_pte() can result in confusion,
because if the source PTE/PMD indicates write permissions, then there
should be no need to check VMA write permissions when restoring migration
entries or PTE-mapping a PMD.
Commit
|
||
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David Hildenbrand
|
1462c52e9f |
mm/huge_memory: conditionally call maybe_mkwrite() and drop pte_wrprotect() in __split_huge_pmd_locked()
No need to call maybe_mkwrite() to then wrprotect if the source PMD was not writable. It's worth nothing that this now allows for PTEs to be writable even if the source PMD was not writable: if vma->vm_page_prot includes write permissions. As documented in commit |
||
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David Hildenbrand
|
5436d65569 |
mm/huge_memory: revert "Partly revert "mm/thp: carry over dirty bit when thp splits on pmd""
This reverts commit |
||
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David Hildenbrand
|
3c811f7883 |
mm/migrate: revert "mm/migrate: fix wrongly apply write bit after mkdirty on sparc64"
This reverts commit |
||
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David Hildenbrand
|
27da93d8e6 |
mm/userfaultfd: don't consider uffd-wp bit of writable migration entries
If we end up with a writable migration entry that has the uffd-wp bit set,
we already messed up: the source PTE/PMD was writable, which means we
could have modified the page without notifying uffd first. Setting the
uffd-wp bit always implies converting migration entries to !writable
migration entries.
Commit
|
||
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Andrew Morton
|
e492cd61b9 | sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes | ||
|
Naoya Horiguchi
|
4737edbbdd |
mm/huge_memory.c: warn with pr_warn_ratelimited instead of VM_WARN_ON_ONCE_FOLIO
split_huge_page_to_list() WARNs when called for huge zero pages, which
sounds to me too harsh because it does not imply a kernel bug, but just
notifies the event to admins. On the other hand, this is considered as
critical by syzkaller and makes its testing less efficient, which seems to
me harmful.
So replace the VM_WARN_ON_ONCE_FOLIO with pr_warn_ratelimited.
Link: https://lkml.kernel.org/r/20230406082004.2185420-1-naoya.horiguchi@linux.dev
Fixes:
|
||
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David Hildenbrand
|
24bf08c437 |
mm/userfaultfd: fix uffd-wp handling for THP migration entries
Looks like what we fixed for hugetlb in commit |
||
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Lorenzo Stoakes
|
7b806d229e |
mm: remove vmf_insert_pfn_xxx_prot() for huge page-table entries
This functionality's sole user, the drm ttm module, removed support for it
in commit
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||
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Kirill A. Shutemov
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23baf831a3 |
mm, treewide: redefine MAX_ORDER sanely
MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Christoph Hellwig
|
66dabbb65d |
mm: return an ERR_PTR from __filemap_get_folio
Instead of returning NULL for all errors, distinguish between: - no entry found and not asked to allocated (-ENOENT) - failed to allocate memory (-ENOMEM) - would block (-EAGAIN) so that callers don't have to guess the error based on the passed in flags. Also pass through the error through the direct callers: filemap_get_folio, filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio. [hch@lst.de: fix null-pointer deref] Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004 Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nilfs2] Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Christoph Hellwig
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1fb130b226 |
mm: don't look at xarray value entries in split_huge_pages_in_file
Patch series "return an ERR_PTR from __filemap_get_folio", v3. __filemap_get_folio and its wrappers can return NULL for three different conditions, which in some cases requires the caller to reverse engineer the decision making. This is fixed by returning an ERR_PTR instead of NULL and thus transporting the reason for the failure. But to make that work we first need to ensure that no xa_value special case is returned and thus return the FGP_ENTRY flag. It turns out that flag is barely used and can usually be deal with in a better way. This patch (of 7): split_huge_pages_in_file never wants to do anything with the special value enties. Switch to using filemap_get_folio to not even see them. Link: https://lkml.kernel.org/r/20230307143410.28031-1-hch@lst.de Link: https://lkml.kernel.org/r/20230307143410.28031-2-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Peter Xu
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3c556d2425 |
mm/thp: rename TRANSPARENT_HUGEPAGE_NEVER_DAX to _UNSUPPORTED
TRANSPARENT_HUGEPAGE_NEVER_DAX has nothing to do with DAX. It's set when has_transparent_hugepage() returns false, checked in hugepage_vma_check() and will disable THP completely if false. Rename it to TRANSPARENT_HUGEPAGE_UNSUPPORTED to reflect its real purpose. [peterx@redhat.com: fix comment, per David] Link: https://lkml.kernel.org/r/ZBMzQW674oHQJV7F@x1n Link: https://lkml.kernel.org/r/20230315171642.1244625-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Kefeng Wang
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cfe3236d32 |
mm: huge_memory: convert __do_huge_pmd_anonymous_page() to use a folio
Patch series "mm: remove cgroup_throttle_swaprate() completely", v2. Convert all the caller functions of cgroup_throttle_swaprate() to use folios, and use folio_throttle_swaprate(), which allows us to remove cgroup_throttle_swaprate() completely. This patch (of 7): Convert from page to folio within __do_huge_pmd_anonymous_page(), as we need the precise page which is to be stored at this PTE in the folio, the function still keep a page as the parameter. Link: https://lkml.kernel.org/r/20230302115835.105364-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20230302115835.105364-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
42b2af2c9b |
mm/userfaultfd: propagate uffd-wp bit when PTE-mapping the huge zeropage
Currently, we'd lose the userfaultfd-wp marker when PTE-mapping a huge
zeropage, resulting in the next write faults in the PMD range not
triggering uffd-wp events.
Various actions (partial MADV_DONTNEED, partial mremap, partial munmap,
partial mprotect) could trigger this. However, most importantly,
un-protecting a single sub-page from the userfaultfd-wp handler when
processing a uffd-wp event will PTE-map the shared huge zeropage and lose
the uffd-wp bit for the remainder of the PMD.
Let's properly propagate the uffd-wp bit to the PMDs.
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <inttypes.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <poll.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <linux/userfaultfd.h>
static size_t pagesize;
static int uffd;
static volatile bool uffd_triggered;
#define barrier() __asm__ __volatile__("": : :"memory")
static void uffd_wp_range(char *start, size_t size, bool wp)
{
struct uffdio_writeprotect uffd_writeprotect;
uffd_writeprotect.range.start = (unsigned long) start;
uffd_writeprotect.range.len = size;
if (wp) {
uffd_writeprotect.mode = UFFDIO_WRITEPROTECT_MODE_WP;
} else {
uffd_writeprotect.mode = 0;
}
if (ioctl(uffd, UFFDIO_WRITEPROTECT, &uffd_writeprotect)) {
fprintf(stderr, "UFFDIO_WRITEPROTECT failed: %d\n", errno);
exit(1);
}
}
static void *uffd_thread_fn(void *arg)
{
static struct uffd_msg msg;
ssize_t nread;
while (1) {
struct pollfd pollfd;
int nready;
pollfd.fd = uffd;
pollfd.events = POLLIN;
nready = poll(&pollfd, 1, -1);
if (nready == -1) {
fprintf(stderr, "poll() failed: %d\n", errno);
exit(1);
}
nread = read(uffd, &msg, sizeof(msg));
if (nread <= 0)
continue;
if (msg.event != UFFD_EVENT_PAGEFAULT ||
!(msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP)) {
printf("FAIL: wrong uffd-wp event fired\n");
exit(1);
}
/* un-protect the single page. */
uffd_triggered = true;
uffd_wp_range((char *)(uintptr_t)msg.arg.pagefault.address,
pagesize, false);
}
return arg;
}
static int setup_uffd(char *map, size_t size)
{
struct uffdio_api uffdio_api;
struct uffdio_register uffdio_register;
pthread_t thread;
uffd = syscall(__NR_userfaultfd,
O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY);
if (uffd < 0) {
fprintf(stderr, "syscall() failed: %d\n", errno);
return -errno;
}
uffdio_api.api = UFFD_API;
uffdio_api.features = UFFD_FEATURE_PAGEFAULT_FLAG_WP;
if (ioctl(uffd, UFFDIO_API, &uffdio_api) < 0) {
fprintf(stderr, "UFFDIO_API failed: %d\n", errno);
return -errno;
}
if (!(uffdio_api.features & UFFD_FEATURE_PAGEFAULT_FLAG_WP)) {
fprintf(stderr, "UFFD_FEATURE_WRITEPROTECT missing\n");
return -ENOSYS;
}
uffdio_register.range.start = (unsigned long) map;
uffdio_register.range.len = size;
uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) < 0) {
fprintf(stderr, "UFFDIO_REGISTER failed: %d\n", errno);
return -errno;
}
pthread_create(&thread, NULL, uffd_thread_fn, NULL);
return 0;
}
int main(void)
{
const size_t size = 4 * 1024 * 1024ull;
char *map, *cur;
pagesize = getpagesize();
map = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "mmap() failed\n");
return -errno;
}
if (madvise(map, size, MADV_HUGEPAGE)) {
fprintf(stderr, "MADV_HUGEPAGE failed\n");
return -errno;
}
if (setup_uffd(map, size))
return 1;
/* Read the whole range, populating zeropages. */
madvise(map, size, MADV_POPULATE_READ);
/* Write-protect the whole range. */
uffd_wp_range(map, size, true);
/* Make sure uffd-wp triggers on each page. */
for (cur = map; cur < map + size; cur += pagesize) {
uffd_triggered = false;
barrier();
/* Trigger a write fault. */
*cur = 1;
barrier();
if (!uffd_triggered) {
printf("FAIL: uffd-wp did not trigger\n");
return 1;
}
}
printf("PASS: uffd-wp triggered\n");
return 0;
}
Link: https://lkml.kernel.org/r/20230302175423.589164-1-david@redhat.com
Fixes:
|
||
|
Linus Torvalds
|
3822a7c409 |
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter". These filters provide users
with finer-grained control over DAMOS's actions. SeongJae has also done
some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series "mm:
support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with his
series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings. The previous BPF-based approach had
shortcomings. See "mm: In-kernel support for memory-deny-write-execute
(MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a per-node
basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage during
compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in ths
series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's series
"mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
"fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest of
the kernel in the series "Simplify the external interface for GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the series
"mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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jlvpAPsFECUBBl20qSue2zCYWnHC7Yk4q9ytTkPB/MMDrFEN9wD/SNKEm2UoK6/K
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
|
||
|
Peter Xu
|
96a9c287e2 |
mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
Nick Bowler reported another sparc64 breakage after the young/dirty
persistent work for page migration (per "Link:" below). That's after a
similar report [2].
It turns out page migration was overlooked, and it wasn't failing before
because page migration was not enabled in the initial report test
environment.
David proposed another way [2] to fix this from sparc64 side, but that
patch didn't land somehow. Neither did I check whether there's any other
arch that has similar issues.
Let's fix it for now as simple as moving the write bit handling to be
after dirty, like what we did before.
Note: this is based on mm-unstable, because the breakage was since 6.1 and
we're at a very late stage of 6.2 (-rc8), so I assume for this specific
case we should target this at 6.3.
[1] https://lore.kernel.org/all/20221021160603.GA23307@u164.east.ru/
[2] https://lore.kernel.org/all/20221212130213.136267-1-david@redhat.com/
Link: https://lkml.kernel.org/r/20230216153059.256739-1-peterx@redhat.com
Fixes:
|
||
|
Jason Gunthorpe
|
d64e2dbc33 |
mm/gup: simplify the external interface functions and consolidate invariants
The GUP family of functions have a complex, but fairly well defined, set of invariants for their arguments. Currently these are sprinkled about, sometimes in duplicate through many functions. Internally we don't follow all the invariants that the external interface has to follow, so place these checks directly at the exported interface. This ensures the internal functions never reach a violated invariant. Remove the duplicated invariant checks. The end result is to make these functions fully internal: __get_user_pages_locked() internal_get_user_pages_fast() __gup_longterm_locked() And all the other functions call directly into one of these. Link: https://lkml.kernel.org/r/5-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Stevens
|
2cf1338454 |
mm: fix khugepaged with shmem_enabled=advise
Pass vm_flags as a parameter to shmem_is_huge, rather than reading the flags from the vm_area_struct in question. This allows the updated flags from hugepage_madvise to be passed to the check, which is necessary because madvise does not update the vm_area_struct's flags until after hugepage_madvise returns. This fixes an issue when shmem_enabled=madvise, where MADV_HUGEPAGE on shmem was not able to register the mm_struct with khugepaged. Prior to |
||
|
Matthew Wilcox (Oracle)
|
f158ed6195 |
mm: convert deferred_split_huge_page() to deferred_split_folio()
Now that both callers use a folio, pass the folio in and save a call to compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-28-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
f8baa6be03 |
mm/huge_memory: convert get_deferred_split_queue() to take a folio
Removes a few calls to compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-27-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
8991de90e9 |
mm/huge_memory: remove page_deferred_list()
Use folio->_deferred_list directly. Link: https://lkml.kernel.org/r/20230111142915.1001531-26-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
4375a553f4 |
mm: move page->deferred_list to folio->_deferred_list
Remove the entire block of definitions for the second tail page, and add the deferred list to the struct folio. This actually moves _deferred_list to a different offset in struct folio because I don't see a need to include the padding. This lets us use list_for_each_entry_safe() in deferred_split_scan() and avoid a number of calls to compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-25-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
f04029f34e |
mm: convert is_transparent_hugepage() to use a folio
Replace a use of page->compound_dtor with its folio equivalent. Link: https://lkml.kernel.org/r/20230111142915.1001531-20-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
94688e8eb4 |
mm: remove folio_pincount_ptr() and head_compound_pincount()
We can use folio->_pincount directly, since all users are guarded by tests of compound/large. Link: https://lkml.kernel.org/r/20230111142915.1001531-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Alistair Popple
|
7d4a8be0c4 |
mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export
mmu_notifier_range_update_to_read_only() was originally introduced in
commit
|
||
|
Kefeng Wang
|
630e7c5ee3 |
mm: huge_memory: convert split_huge_pages_all() to use a folio
Straightforwardly convert split_huge_pages_all() to use a folio. Link: https://lkml.kernel.org/r/20221229122503.149083-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yin Fengwei
|
81e506bec9 |
mm/thp: check and bail out if page in deferred queue already
Kernel build regression with LLVM was reported here: https://lore.kernel.org/all/Y1GCYXGtEVZbcv%2F5@dev-arch.thelio-3990X/ with commit |
||
|
Kefeng Wang
|
6a6fe9ebd5 |
mm: swap: convert mark_page_lazyfree() to folio_mark_lazyfree()
mark_page_lazyfree() and the callers are converted to use folio, this rename and make it to take in a folio argument instead of calling page_folio(). Link: https://lkml.kernel.org/r/20221209020618.190306-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
fc986a38b6 |
mm: huge_memory: convert madvise_free_huge_pmd to use a folio
Using folios instead of pages removes several calls to compound_head(), Link: https://lkml.kernel.org/r/20221207023431.151008-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
f1eb1bacfb |
mm/uffd: always wr-protect pte in pte|pmd_mkuffd_wp()
This patch is a cleanup to always wr-protect pte/pmd in mkuffd_wp paths.
The reasons I still think this patch is worthwhile, are:
(1) It is a cleanup already; diffstat tells.
(2) It just feels natural after I thought about this, if the pte is uffd
protected, let's remove the write bit no matter what it was.
(2) Since x86 is the only arch that supports uffd-wp, it also redefines
pte|pmd_mkuffd_wp() in that it should always contain removals of
write bits. It means any future arch that want to implement uffd-wp
should naturally follow this rule too. It's good to make it a
default, even if with vm_page_prot changes on VM_UFFD_WP.
(3) It covers more than vm_page_prot. So no chance of any potential
future "accident" (like pte_mkdirty() sparc64 or loongarch, even
though it just got its pte_mkdirty fixed <1 month ago). It'll be
fairly clear when reading the code too that we don't worry anything
before a pte_mkuffd_wp() on uncertainty of the write bit.
We may call pte_wrprotect() one more time in some paths (e.g. thp split),
but that should be fully local bitop instruction so the overhead should be
negligible.
Although this patch should logically also fix all the known issues on
uffd-wp too recently on page migration (not for numa hint recovery - that
may need another explcit pte_wrprotect), but this is not the plan for that
fix. So no fixes, and stable doesn't need this.
Link: https://lkml.kernel.org/r/20221214201533.1774616-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ives van Hoorne <ives@codesandbox.io>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Linus Torvalds
|
8fa590bf34 |
ARM64:
* Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. * Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. * Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on (see merge commit |
||
|
Linus Torvalds
|
e2ca6ba6ba |
MM patches for 6.2-rc1.
- More userfaultfs work from Peter Xu. - Several convert-to-folios series from Sidhartha Kumar and Huang Ying. - Some filemap cleanups from Vishal Moola. - David Hildenbrand added the ability to selftest anon memory COW handling. - Some cpuset simplifications from Liu Shixin. - Addition of vmalloc tracing support by Uladzislau Rezki. - Some pagecache folioifications and simplifications from Matthew Wilcox. - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use it. - Miguel Ojeda contributed some cleanups for our use of the __no_sanitize_thread__ gcc keyword. This series shold have been in the non-MM tree, my bad. - Naoya Horiguchi improved the interaction between memory poisoning and memory section removal for huge pages. - DAMON cleanups and tuneups from SeongJae Park - Tony Luck fixed the handling of COW faults against poisoned pages. - Peter Xu utilized the PTE marker code for handling swapin errors. - Hugh Dickins reworked compound page mapcount handling, simplifying it and making it more efficient. - Removal of the autonuma savedwrite infrastructure from Nadav Amit and David Hildenbrand. - zram support for multiple compression streams from Sergey Senozhatsky. - David Hildenbrand reworked the GUP code's R/O long-term pinning so that drivers no longer need to use the FOLL_FORCE workaround which didn't work very well anyway. - Mel Gorman altered the page allocator so that local IRQs can remnain enabled during per-cpu page allocations. - Vishal Moola removed the try_to_release_page() wrapper. - Stefan Roesch added some per-BDI sysfs tunables which are used to prevent network block devices from dirtying excessive amounts of pagecache. - David Hildenbrand did some cleanup and repair work on KSM COW breaking. - Nhat Pham and Johannes Weiner have implemented writeback in zswap's zsmalloc backend. - Brian Foster has fixed a longstanding corner-case oddity in file[map]_write_and_wait_range(). - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang Chen. - Shiyang Ruan has done some work on fsdax, to make its reflink mode work better under xfstests. Better, but still not perfect. - Christoph Hellwig has removed the .writepage() method from several filesystems. They only need .writepages(). - Yosry Ahmed wrote a series which fixes the memcg reclaim target beancounting. - David Hildenbrand has fixed some of our MM selftests for 32-bit machines. - Many singleton patches, as usual. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY5j6ZwAKCRDdBJ7gKXxA jkDYAP9qNeVqp9iuHjZNTqzMXkfmJPsw2kmy2P+VdzYVuQRcJgEAgoV9d7oMq4ml CodAgiA51qwzId3GRytIo/tfWZSezgA= =d19R -----END PGP SIGNATURE----- Merge tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - More userfaultfs work from Peter Xu - Several convert-to-folios series from Sidhartha Kumar and Huang Ying - Some filemap cleanups from Vishal Moola - David Hildenbrand added the ability to selftest anon memory COW handling - Some cpuset simplifications from Liu Shixin - Addition of vmalloc tracing support by Uladzislau Rezki - Some pagecache folioifications and simplifications from Matthew Wilcox - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use it - Miguel Ojeda contributed some cleanups for our use of the __no_sanitize_thread__ gcc keyword. This series should have been in the non-MM tree, my bad - Naoya Horiguchi improved the interaction between memory poisoning and memory section removal for huge pages - DAMON cleanups and tuneups from SeongJae Park - Tony Luck fixed the handling of COW faults against poisoned pages - Peter Xu utilized the PTE marker code for handling swapin errors - Hugh Dickins reworked compound page mapcount handling, simplifying it and making it more efficient - Removal of the autonuma savedwrite infrastructure from Nadav Amit and David Hildenbrand - zram support for multiple compression streams from Sergey Senozhatsky - David Hildenbrand reworked the GUP code's R/O long-term pinning so that drivers no longer need to use the FOLL_FORCE workaround which didn't work very well anyway - Mel Gorman altered the page allocator so that local IRQs can remnain enabled during per-cpu page allocations - Vishal Moola removed the try_to_release_page() wrapper - Stefan Roesch added some per-BDI sysfs tunables which are used to prevent network block devices from dirtying excessive amounts of pagecache - David Hildenbrand did some cleanup and repair work on KSM COW breaking - Nhat Pham and Johannes Weiner have implemented writeback in zswap's zsmalloc backend - Brian Foster has fixed a longstanding corner-case oddity in file[map]_write_and_wait_range() - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang Chen - Shiyang Ruan has done some work on fsdax, to make its reflink mode work better under xfstests. Better, but still not perfect - Christoph Hellwig has removed the .writepage() method from several filesystems. They only need .writepages() - Yosry Ahmed wrote a series which fixes the memcg reclaim target beancounting - David Hildenbrand has fixed some of our MM selftests for 32-bit machines - Many singleton patches, as usual * tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (313 commits) mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio mm: mmu_gather: allow more than one batch of delayed rmaps mm: fix typo in struct pglist_data code comment kmsan: fix memcpy tests mm: add cond_resched() in swapin_walk_pmd_entry() mm: do not show fs mm pc for VM_LOCKONFAULT pages selftests/vm: ksm_functional_tests: fixes for 32bit selftests/vm: cow: fix compile warning on 32bit selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions mm/gup_test: fix PIN_LONGTERM_TEST_READ with highmem mm,thp,rmap: fix races between updates of subpages_mapcount mm: memcg: fix swapcached stat accounting mm: add nodes= arg to memory.reclaim mm: disable top-tier fallback to reclaim on proactive reclaim selftests: cgroup: make sure reclaim target memcg is unprotected selftests: cgroup: refactor proactive reclaim code to reclaim_until() mm: memcg: fix stale protection of reclaim target memcg mm/mmap: properly unaccount memory on mas_preallocate() failure omfs: remove ->writepage jfs: remove ->writepage ... |
||
|
Linus Torvalds
|
ce8a79d560 |
for-6.2/block-2022-12-08
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Merge tag 'for-6.2/block-2022-12-08' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull requests via Christoph:
- Support some passthrough commands without CAP_SYS_ADMIN (Kanchan
Joshi)
- Refactor PCIe probing and reset (Christoph Hellwig)
- Various fabrics authentication fixes and improvements (Sagi
Grimberg)
- Avoid fallback to sequential scan due to transient issues (Uday
Shankar)
- Implement support for the DEAC bit in Write Zeroes (Christoph
Hellwig)
- Allow overriding the IEEE OUI and firmware revision in configfs
for nvmet (Aleksandr Miloserdov)
- Force reconnect when number of queue changes in nvmet (Daniel
Wagner)
- Minor fixes and improvements (Uros Bizjak, Joel Granados, Sagi
Grimberg, Christoph Hellwig, Christophe JAILLET)
- Fix and cleanup nvme-fc req allocation (Chaitanya Kulkarni)
- Use the common tagset helpers in nvme-pci driver (Christoph
Hellwig)
- Cleanup the nvme-pci removal path (Christoph Hellwig)
- Use kstrtobool() instead of strtobool (Christophe JAILLET)
- Allow unprivileged passthrough of Identify Controller (Joel
Granados)
- Support io stats on the mpath device (Sagi Grimberg)
- Minor nvmet cleanup (Sagi Grimberg)
- MD pull requests via Song:
- Code cleanups (Christoph)
- Various fixes
- Floppy pull request from Denis:
- Fix a memory leak in the init error path (Yuan)
- Series fixing some batch wakeup issues with sbitmap (Gabriel)
- Removal of the pktcdvd driver that was deprecated more than 5 years
ago, and subsequent removal of the devnode callback in struct
block_device_operations as no users are now left (Greg)
- Fix for partition read on an exclusively opened bdev (Jan)
- Series of elevator API cleanups (Jinlong, Christoph)
- Series of fixes and cleanups for blk-iocost (Kemeng)
- Series of fixes and cleanups for blk-throttle (Kemeng)
- Series adding concurrent support for sync queues in BFQ (Yu)
- Series bringing drbd a bit closer to the out-of-tree maintained
version (Christian, Joel, Lars, Philipp)
- Misc drbd fixes (Wang)
- blk-wbt fixes and tweaks for enable/disable (Yu)
- Fixes for mq-deadline for zoned devices (Damien)
- Add support for read-only and offline zones for null_blk
(Shin'ichiro)
- Series fixing the delayed holder tracking, as used by DM (Yu,
Christoph)
- Series enabling bio alloc caching for IRQ based IO (Pavel)
- Series enabling userspace peer-to-peer DMA (Logan)
- BFQ waker fixes (Khazhismel)
- Series fixing elevator refcount issues (Christoph, Jinlong)
- Series cleaning up references around queue destruction (Christoph)
- Series doing quiesce by tagset, enabling cleanups in drivers
(Christoph, Chao)
- Series untangling the queue kobject and queue references (Christoph)
- Misc fixes and cleanups (Bart, David, Dawei, Jinlong, Kemeng, Ye,
Yang, Waiman, Shin'ichiro, Randy, Pankaj, Christoph)
* tag 'for-6.2/block-2022-12-08' of git://git.kernel.dk/linux: (247 commits)
blktrace: Fix output non-blktrace event when blk_classic option enabled
block: sed-opal: Don't include <linux/kernel.h>
sed-opal: allow using IOC_OPAL_SAVE for locking too
blk-cgroup: Fix typo in comment
block: remove bio_set_op_attrs
nvmet: don't open-code NVME_NS_ATTR_RO enumeration
nvme-pci: use the tagset alloc/free helpers
nvme: add the Apple shared tag workaround to nvme_alloc_io_tag_set
nvme: only set reserved_tags in nvme_alloc_io_tag_set for fabrics controllers
nvme: consolidate setting the tagset flags
nvme: pass nr_maps explicitly to nvme_alloc_io_tag_set
block: bio_copy_data_iter
nvme-pci: split out a nvme_pci_ctrl_is_dead helper
nvme-pci: return early on ctrl state mismatch in nvme_reset_work
nvme-pci: rename nvme_disable_io_queues
nvme-pci: cleanup nvme_suspend_queue
nvme-pci: remove nvme_pci_disable
nvme-pci: remove nvme_disable_admin_queue
nvme: merge nvme_shutdown_ctrl into nvme_disable_ctrl
nvme: use nvme_wait_ready in nvme_shutdown_ctrl
...
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||
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David Hildenbrand
|
cb8d863313 |
mm: remove VM_FAULT_WRITE
All users -- GUP and KSM -- are gone, let's just remove it. Link: https://lkml.kernel.org/r/20221021101141.84170-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Peter Xu
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e833bc5034 |
mm/thp: re-apply mkdirty for small pages after split
We used to have |
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David Hildenbrand
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84209e87c6 |
mm/gup: reliable R/O long-term pinning in COW mappings
We already support reliable R/O pinning of anonymous memory. However,
assume we end up pinning (R/O long-term) a pagecache page or the shared
zeropage inside a writable private ("COW") mapping. The next write access
will trigger a write-fault and replace the pinned page by an exclusive
anonymous page in the process page tables to break COW: the pinned page no
longer corresponds to the page mapped into the process' page table.
Now that FAULT_FLAG_UNSHARE can break COW on anything mapped into a
COW mapping, let's properly break COW first before R/O long-term
pinning something that's not an exclusive anon page inside a COW
mapping. FAULT_FLAG_UNSHARE will break COW and map an exclusive anon page
instead that can get pinned safely.
With this change, we can stop using FOLL_FORCE|FOLL_WRITE for reliable
R/O long-term pinning in COW mappings.
With this change, the new R/O long-term pinning tests for non-anonymous
memory succeed:
# [RUN] R/O longterm GUP pin ... with shared zeropage
ok 151 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd
ok 152 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with tmpfile
ok 153 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with huge zeropage
ok 154 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd hugetlb (2048 kB)
ok 155 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd hugetlb (1048576 kB)
ok 156 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with shared zeropage
ok 157 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd
ok 158 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with tmpfile
ok 159 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with huge zeropage
ok 160 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (2048 kB)
ok 161 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (1048576 kB)
ok 162 Longterm R/O pin is reliable
Note 1: We don't care about short-term R/O-pinning, because they have
snapshot semantics: they are not supposed to observe modifications that
happen after pinning.
As one example, assume we start direct I/O to read from a page and store
page content into a file: modifications to page content after starting
direct I/O are not guaranteed to end up in the file. So even if we'd pin
the shared zeropage, the end result would be as expected -- getting zeroes
stored to the file.
Note 2: For shared mappings we'll now always fallback to the slow path to
lookup the VMA when R/O long-term pining. While that's the necessary price
we have to pay right now, it's actually not that bad in practice: most
FOLL_LONGTERM users already specify FOLL_WRITE, for example, along with
FOLL_FORCE because they tried dealing with COW mappings correctly ...
Note 3: For users that use FOLL_LONGTERM right now without FOLL_WRITE,
such as VFIO, we'd now no longer pin the shared zeropage. Instead, we'd
populate exclusive anon pages that we can pin. There was a concern that
this could affect the memlock limit of existing setups.
For example, a VM running with VFIO could run into the memlock limit and
fail to run. However, we essentially had the same behavior already in
commit
|
||
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David Hildenbrand
|
cdc5021cda |
mm: add early FAULT_FLAG_UNSHARE consistency checks
For now, FAULT_FLAG_UNSHARE only applies to anonymous pages, which implies a COW mapping. Let's hide FAULT_FLAG_UNSHARE early if we're not dealing with a COW mapping, such that we treat it like a read fault as documented and don't have to worry about the flag throughout all fault handlers. While at it, centralize the check for mutual exclusion of FAULT_FLAG_UNSHARE and FAULT_FLAG_WRITE and just drop the check that either flag is set in the WP handler. Link: https://lkml.kernel.org/r/20221116102659.70287-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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David Hildenbrand
|
6a56ccbcf6 |
mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite
commit |
||
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David Hildenbrand
|
c27f479ef5 |
mm/huge_memory: try avoiding write faults when changing PMD protection
Let's replicate what we have for PTEs in can_change_pte_writable() also for PMDs. While this might look like a pure performance improvement, we'll us this to get rid of savedwrite handling in do_huge_pmd_numa_page() next. Place do_huge_pmd_numa_page() strategically good for that purpose. Note that MM_CP_TRY_CHANGE_WRITABLE is currently only set when we come via mprotect_fixup(). Link: https://lkml.kernel.org/r/20221108174652.198904-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Hugh Dickins <hughd@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Hugh Dickins
|
96d82deb74 |
mm,thp,rmap: clean up the end of __split_huge_pmd_locked()
It's hard to add a page_add_anon_rmap() into __split_huge_pmd_locked()'s HPAGE_PMD_NR set_pte_at() loop, without wincing at the "freeze" case's HPAGE_PMD_NR page_remove_rmap() loop below it. It's just a mistake to add rmaps in the "freeze" (insert migration entries prior to splitting huge page) case: the pmd_migration case already avoids doing that, so just follow its lead. page_add_ref() versus put_page() likewise. But why is one more put_page() needed in the "freeze" case? Because it's removing the pmd rmap, already removed when pmd_migration (and freeze and pmd_migration are mutually exclusive cases). Link: https://lkml.kernel.org/r/d43748aa-fece-e0b9-c4ab-f23c9ebc9011@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Carpenter <error27@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hugh Dickins
|
be5ef2d9b0 |
mm,thp,rmap: subpages_mapcount of PTE-mapped subpages
Patch series "mm,thp,rmap: rework the use of subpages_mapcount", v2. This patch (of 3): Following suggestion from Linus, instead of counting every PTE map of a compound page in subpages_mapcount, just count how many of its subpages are PTE-mapped: this yields the exact number needed for NR_ANON_MAPPED and NR_FILE_MAPPED stats, without any need for a locked scan of subpages; and requires updating the count less often. This does then revert total_mapcount() and folio_mapcount() to needing a scan of subpages; but they are inherently racy, and need no locking, so Linus is right that the scans are much better done there. Plus (unlike in 6.1 and previous) subpages_mapcount lets us avoid the scan in the common case of no PTE maps. And page_mapped() and folio_mapped() remain scanless and just as efficient with the new meaning of subpages_mapcount: those are the functions which I most wanted to remove the scan from. The updated page_dup_compound_rmap() is no longer suitable for use by anon THP's __split_huge_pmd_locked(); but page_add_anon_rmap() can be used for that, so long as its VM_BUG_ON_PAGE(!PageLocked) is deleted. Evidence is that this way goes slightly faster than the previous implementation for most cases; but significantly faster in the (now scanless) pmds after ptes case, which started out at 870ms and was brought down to 495ms by the previous series, now takes around 105ms. Link: https://lkml.kernel.org/r/a5849eca-22f1-3517-bf29-95d982242742@google.com Link: https://lkml.kernel.org/r/eec17e16-4e1-7c59-f1bc-5bca90dac919@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Carpenter <error27@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hugh Dickins
|
9bd3155ed8 |
mm,thp,rmap: lock_compound_mapcounts() on THP mapcounts
Fix the races in maintaining compound_mapcount, subpages_mapcount and
subpage _mapcount by using PG_locked in the first tail of any compound
page for a bit_spin_lock() on such modifications; skipping the usual
atomic operations on those fields in this case.
Bring page_remove_file_rmap() and page_remove_anon_compound_rmap() back
into page_remove_rmap() itself. Rearrange page_add_anon_rmap() and
page_add_file_rmap() and page_remove_rmap() to follow the same "if
(compound) {lock} else if (PageCompound) {lock} else {atomic}" pattern
(with a PageTransHuge in the compound test, like before, to avoid BUG_ONs
and optimize away that block when THP is not configured). Move all the
stats updates outside, after the bit_spin_locked section, so that it is
sure to be a leaf lock.
Add page_dup_compound_rmap() to manage compound locking versus atomics in
sync with the rest. In particular, hugetlb pages are still using the
atomics: to avoid unnecessary interference there, and because they never
have subpage mappings; but this exception can easily be changed.
Conveniently, page_dup_compound_rmap() turns out to suit an anon THP's
__split_huge_pmd_locked() too.
bit_spin_lock() is not popular with PREEMPT_RT folks: but PREEMPT_RT
sensibly excludes TRANSPARENT_HUGEPAGE already, so its only exposure is to
the non-hugetlb non-THP pte-mapped compound pages (with large folios being
currently dependent on TRANSPARENT_HUGEPAGE). There is never any scan of
subpages in this case; but we have chosen to use PageCompound tests rather
than PageTransCompound tests to gate the use of lock_compound_mapcounts(),
so that page_mapped() is correct on all compound pages, whether or not
TRANSPARENT_HUGEPAGE is enabled: could that be a problem for PREEMPT_RT,
when there is contention on the lock - under heavy concurrent forking for
example? If so, then it can be turned into a sleeping lock (like
folio_lock()) when PREEMPT_RT.
A simple 100 X munmap(mmap(2GB, MAP_SHARED|MAP_POPULATE, tmpfs), 2GB) took
18 seconds on small pages, and used to take 1 second on huge pages, but
now takes 115 milliseconds on huge pages. Mapping by pmds a second time
used to take 860ms and now takes 86ms; mapping by pmds after mapping by
ptes (when the scan is needed) used to take 870ms and now takes 495ms.
Mapping huge pages by ptes is largely unaffected but variable: between 5%
faster and 5% slower in what I've recorded. Contention on the lock is
likely to behave worse than contention on the atomics behaved.
Link: https://lkml.kernel.org/r/1b42bd1a-8223-e827-602f-d466c2db7d3c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
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Hugh Dickins
|
cb67f4282b |
mm,thp,rmap: simplify compound page mapcount handling
Compound page (folio) mapcount calculations have been different for anon and file (or shmem) THPs, and involved the obscure PageDoubleMap flag. And each huge mapping and unmapping of a file (or shmem) THP involved atomically incrementing and decrementing the mapcount of every subpage of that huge page, dirtying many struct page cachelines. Add subpages_mapcount field to the struct folio and first tail page, so that the total of subpage mapcounts is available in one place near the head: then page_mapcount() and total_mapcount() and page_mapped(), and their folio equivalents, are so quick that anon and file and hugetlb don't need to be optimized differently. Delete the unloved PageDoubleMap. page_add and page_remove rmap functions must now maintain the subpages_mapcount as well as the subpage _mapcount, when dealing with pte mappings of huge pages; and correct maintenance of NR_ANON_MAPPED and NR_FILE_MAPPED statistics still needs reading through the subpages, using nr_subpages_unmapped() - but only when first or last pmd mapping finds subpages_mapcount raised (double-map case, not the common case). But are those counts (used to decide when to split an anon THP, and in vmscan's pagecache_reclaimable heuristic) correctly maintained? Not quite: since page_remove_rmap() (and also split_huge_pmd()) is often called without page lock, there can be races when a subpage pte mapcount 0<->1 while compound pmd mapcount 0<->1 is scanning - races which the previous implementation had prevented. The statistics might become inaccurate, and even drift down until they underflow through 0. That is not good enough, but is better dealt with in a followup patch. Update a few comments on first and second tail page overlaid fields. hugepage_add_new_anon_rmap() has to "increment" compound_mapcount, but subpages_mapcount and compound_pincount are already correctly at 0, so delete its reinitialization of compound_pincount. A simple 100 X munmap(mmap(2GB, MAP_SHARED|MAP_POPULATE, tmpfs), 2GB) took 18 seconds on small pages, and used to take 1 second on huge pages, but now takes 119 milliseconds on huge pages. Mapping by pmds a second time used to take 860ms and now takes 92ms; mapping by pmds after mapping by ptes (when the scan is needed) used to take 870ms and now takes 495ms. But there might be some benchmarks which would show a slowdown, because tail struct pages now fall out of cache until final freeing checks them. Link: https://lkml.kernel.org/r/47ad693-717-79c8-e1ba-46c3a6602e48@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |