Kernel for Galaxy S24, rebased on CLO sources (WIP)
Patch series "userfaultfd move option", v6. This patch series introduces UFFDIO_MOVE feature to userfaultfd, which has long been implemented and maintained by Andrea in his local tree [1], but was not upstreamed due to lack of use cases where this approach would be better than allocating a new page and copying the contents. Previous upstraming attempts could be found at [6] and [7]. UFFDIO_COPY performs ~20% better than UFFDIO_MOVE when the application needs pages to be allocated [2]. However, with UFFDIO_MOVE, if pages are available (in userspace) for recycling, as is usually the case in heap compaction algorithms, then we can avoid the page allocation and memcpy (done by UFFDIO_COPY). Also, since the pages are recycled in the userspace, we avoid the need to release (via madvise) the pages back to the kernel [3]. We see over 40% reduction (on a Google pixel 6 device) in the compacting thread's completion time by using UFFDIO_MOVE vs. UFFDIO_COPY. This was measured using a benchmark that emulates a heap compaction implementation using userfaultfd (to allow concurrent accesses by application threads). More details of the usecase are explained in [3]. Furthermore, UFFDIO_MOVE enables moving swapped-out pages without touching them within the same vma. Today, it can only be done by mremap, however it forces splitting the vma. TODOs for follow-up improvements: - cross-mm support. Known differences from single-mm and missing pieces: - memcg recharging (might need to isolate pages in the process) - mm counters - cross-mm deposit table moves - cross-mm test - document the address space where src and dest reside in struct uffdio_move - TLB flush batching. Will require extensive changes to PTL locking in move_pages_pte(). OTOH that might let us reuse parts of mremap code. This patch (of 5): For now, folio_move_anon_rmap() was only used to move a folio to a different anon_vma after fork(), whereby the root anon_vma stayed unchanged. For that, it was sufficient to hold the folio lock when calling folio_move_anon_rmap(). However, we want to make use of folio_move_anon_rmap() to move folios between VMAs that have a different root anon_vma. As folio_referenced() performs an RMAP walk without holding the folio lock but only holding the anon_vma in read mode, holding the folio lock is insufficient. When moving to an anon_vma with a different root anon_vma, we'll have to hold both, the folio lock and the anon_vma lock in write mode. Consequently, whenever we succeeded in folio_lock_anon_vma_read() to read-lock the anon_vma, we have to re-check if the mapping was changed in the meantime. If that was the case, we have to retry. Note that folio_move_anon_rmap() must only be called if the anon page is exclusive to a process, and must not be called on KSM folios. This is a preparation for UFFDIO_MOVE, which will hold the folio lock, the anon_vma lock in write mode, and the mmap_lock in read mode. Link: https://lkml.kernel.org/r/20231206103702.3873743-1-surenb@google.com Link: https://lkml.kernel.org/r/20231206103702.3873743-2-surenb@google.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: kernel-team@android.com Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Nicolas Geoffray <ngeoffray@google.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> (cherry picked from commit 880a99b60d467eefd96322e27b0a8c0b805dfa43) Bug: 274911254 Change-Id: Iad9619c0273e050af26356f66ae9fc88b56d68bd Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> |
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android | ||
arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
rust | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
.rustfmt.toml | ||
BUILD.bazel | ||
build.config.aarch64 | ||
build.config.allmodconfig | ||
build.config.allmodconfig.aarch64 | ||
build.config.allmodconfig.arm | ||
build.config.allmodconfig.x86_64 | ||
build.config.amlogic | ||
build.config.arm | ||
build.config.common | ||
build.config.constants | ||
build.config.crashdump | ||
build.config.crashdump.aarch64 | ||
build.config.crashdump.x86_64 | ||
build.config.db845c | ||
build.config.gki | ||
build.config.gki_kasan | ||
build.config.gki_kasan.aarch64 | ||
build.config.gki_kasan.x86_64 | ||
build.config.gki_kprobes | ||
build.config.gki_kprobes.aarch64 | ||
build.config.gki_kprobes.x86_64 | ||
build.config.gki-debug.aarch64 | ||
build.config.gki-debug.x86_64 | ||
build.config.gki.aarch64 | ||
build.config.gki.aarch64.fips140 | ||
build.config.gki.riscv64 | ||
build.config.gki.x86_64 | ||
build.config.khwasan | ||
build.config.microdroid | ||
build.config.microdroid.aarch64 | ||
build.config.microdroid.x86_64 | ||
build.config.riscv64 | ||
build.config.rockchip | ||
build.config.rockpi4 | ||
build.config.x86_64 | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
Kconfig.ext | ||
MAINTAINERS | ||
Makefile | ||
modules.bzl | ||
OWNERS | ||
README | ||
README.md |
How do I submit patches to Android Common Kernels
-
BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
EXPORT_SYMBOL_GPL()
require an in-tree modular driver that uses the symbol -- so include the new driver or changes to an existing driver in the same patchset as the export. - When sending patches upstream, the commit message must contain a clear case for why the patch is needed and beneficial to the community. Enabling out-of-tree drivers or functionality is not not a persuasive case.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
-
LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.
Common Kernel patch requirements
- All patches must conform to the Linux kernel coding standards and pass
scripts/checkpatch.pl
- Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
- If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch:
UPSTREAM:
,BACKPORT:
,FROMGIT:
,FROMLIST:
, orANDROID:
. - All patches must have a
Change-Id:
tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html) - If an Android bug has been assigned, there must be a
Bug:
tag. - All patches must have a
Signed-off-by:
tag by the author and the submitter
Additional requirements are listed below based on patch type
Requirements for backports from mainline Linux: UPSTREAM:
, BACKPORT:
- If the patch is a cherry-pick from Linux mainline with no changes at all
- tag the patch subject with
UPSTREAM:
. - add upstream commit information with a
(cherry picked from commit ...)
line - Example:
- if the upstream commit message is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
UPSTREAM: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch requires any changes from the upstream version, tag the patch with
BACKPORT:
instead ofUPSTREAM:
.- use the same tags as
UPSTREAM:
- add comments about the changes under the
(cherry picked from commit ...)
line - Example:
- use the same tags as
BACKPORT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
[joe: Resolved minor conflict in drivers/foo/bar.c ]
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for other backports: FROMGIT:
, FROMLIST:
,
- If the patch has been merged into an upstream maintainer tree, but has not yet
been merged into Linux mainline
- tag the patch subject with
FROMGIT:
- add info on where the patch came from as
(cherry picked from commit <sha1> <repo> <branch>)
. This must be a stable maintainer branch (not rebased, so don't uselinux-next
for example). - if changes were required, use
BACKPORT: FROMGIT:
- Example:
- if the commit message in the maintainer tree is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
FROMGIT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
(cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch has been submitted to LKML, but not accepted into any maintainer tree
- tag the patch subject with
FROMLIST:
- add a
Link:
tag with a link to the submittal on lore.kernel.org - add a
Bug:
tag with the Android bug (required for patches not accepted into a maintainer tree) - if changes were required, use
BACKPORT: FROMLIST:
- Example:
- tag the patch subject with
FROMLIST: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for Android-specific patches: ANDROID:
- If the patch is fixing a bug to Android-specific code
- tag the patch subject with
ANDROID:
- add a
Fixes:
tag that cites the patch with the bug - Example:
- tag the patch subject with
ANDROID: fix android-specific bug in foobar.c
This is the detailed description of the important fix
Fixes: 1234abcd2468 ("foobar: add cool feature")
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch is a new feature
- tag the patch subject with
ANDROID:
- add a
Bug:
tag with the Android bug (required for android-specific features)
- tag the patch subject with