- 04 Sep, 2024 40 commits
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Liam R. Howlett authored
Instead of zeroing the vma tree and then overwriting the area, let the area be overwritten and then clean up the gathered vmas using vms_complete_munmap_vmas(). To ensure locking is downgraded correctly, the mm is set regardless of MAP_FIXED or not (NULL vma). If a driver is mapping over an existing vma, then clear the ptes before the call_mmap() invocation. This is done using the vms_clean_up_area() helper. If there is a close vm_ops, that must also be called to ensure any cleanup is done before mapping over the area. This also means that calling open has been added to the abort of an unmap operation, for now. Since vm_ops->open() and vm_ops->close() are not always undo each other (state cleanup may exist in ->close() that is lost forever), the code cannot be left in this way, but that change has been isolated to another commit to make this point very obvious for traceability. Temporarily keep track of the number of pages that will be removed and reduce the charged amount. This also drops the validate_mm() call in the vma_expand() function. It is necessary to drop the validate as it would fail since the mm map_count would be incorrect during a vma expansion, prior to the cleanup from vms_complete_munmap_vmas(). Clean up the error handing of the vms_gather_munmap_vmas() by calling the verification within the function. Link: https://lkml.kernel.org/r/20240830040101.822209-15-Liam.Howlett@oracle.comSigned-off-by:
Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by:
Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Liam R. Howlett authored
With the only caller to unmap_region() being the error path of mmap_region(), the argument list can be significantly reduced. Link: https://lkml.kernel.org/r/20240830040101.822209-14-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Set the start and end address for munmap when the prev and next are gathered. This is needed to avoid incorrect addresses being used during the vms_complete_munmap_vmas() function if the prev/next vma are expanded. Add a new helper vms_complete_pte_clear(), which is needed later and will avoid growing the argument list to unmap_region() beyond the 9 it already has. Link: https://lkml.kernel.org/r/20240830040101.822209-13-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Instead of moving (or leaving) the vma iterator pointing at the previous vma, leave it pointing at the insert location. Pointing the vma iterator at the insert location allows for a cleaner walk of the vma tree for MAP_FIXED and the no expansion cases. The vma_prev() call in the case of merging the previous vma is equivalent to vma_iter_prev_range(), since the vma iterator will be pointing to the location just before the previous vma. This change needs to export abort_munmap_vmas() from mm/vma. Link: https://lkml.kernel.org/r/20240830040101.822209-12-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Adding support for a NULL vma means the init_vma_munmap() can be initialized for a less error-prone process when calling vms_complete_munmap_vmas() later on. Link: https://lkml.kernel.org/r/20240830040101.822209-11-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Open code the do_vmi_align_munmap() call so that it can be broken up later in the series. This requires exposing a few more vma operations. Link: https://lkml.kernel.org/r/20240830040101.822209-10-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
mmap_region is already passed sanitized addr and len, so change the call to do_vmi_munmap() to do_vmi_align_munmap() and inline the other checks. The inlining of the function and checks is an intermediate step in the series so future patches are easier to follow. Link: https://lkml.kernel.org/r/20240830040101.822209-9-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
vma_complete() will need to be called during an unsafe time to call validate_mm(). Extract the call in all places now so that only one location can be modified in the next change. Link: https://lkml.kernel.org/r/20240830040101.822209-8-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Clean up the code by changing the munmap operation to use a structure for the accounting and munmap variables. Since remove_mt() is only called in one location and the contents will be reduced to almost nothing. The remains of the function can be added to vms_complete_munmap_vmas(). Link: https://lkml.kernel.org/r/20240830040101.822209-7-Liam.Howlett@oracle.comSigned-off-by:
Suren Baghdasaryan <surenb@google.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
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Liam R. Howlett authored
Use a structure to pass along all the necessary information and counters involved in removing vmas from the mm_struct. Update vmi_ function names to vms_ to indicate the first argument type change. Link: https://lkml.kernel.org/r/20240830040101.822209-6-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Create vmi_gather_munmap_vmas() to handle the gathering of vmas into a detached maple tree for removal later. Part of the gathering is the splitting of vmas that span the boundary. Link: https://lkml.kernel.org/r/20240830040101.822209-5-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Extract all necessary operations that need to be completed after the vma maple tree is updated from a munmap() operation. Extracting this makes the later patch in the series easier to understand. Link: https://lkml.kernel.org/r/20240830040101.822209-4-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Extract clean up of failed munmap() operations from do_vmi_align_munmap(). This simplifies later patches in the series. It is worth noting that the mas_for_each() loop now has a different upper limit. This should not change the number of vmas visited for reattaching to the main vma tree (mm_mt), as all vmas are reattached in both scenarios. Link: https://lkml.kernel.org/r/20240830040101.822209-3-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
Patch series "Avoid MAP_FIXED gap exposure", v8. It is now possible to walk the vma tree using the rcu read locks and is beneficial to do so to reduce lock contention. Doing so while a MAP_FIXED mapping is executing means that a reader may see a gap in the vma tree that should never logically exist - and does not when using the mmap lock in read mode. The temporal gap exists because mmap_region() calls munmap() prior to installing the new mapping. This patch set stops rcu readers from seeing the temporal gap by splitting up the munmap() function into two parts. The first part prepares the vma tree for modifications by doing the necessary splits and tracks the vmas marked for removal in a side tree. The second part completes the munmapping of the vmas after the vma tree has been overwritten (either by a MAP_FIXED replacement vma or by a NULL in the munmap() case). Please note that rcu walkers will still be able to see a temporary state of split vmas that may be in the process of being removed, but the temporal gap will not be exposed. vma_start_write() are called on both parts of the split vma, so this state is detectable. If existing vmas have a vm_ops->close(), then they will be called prior to mapping the new vmas (and ptes are cleared out). Without calling ->close(), hugetlbfs tests fail (hugemmap06 specifically) due to resources still being marked as 'busy'. Unfortunately, calling the corresponding ->open() may not restore the state of the vmas, so it is safer to keep the existing failure scenario where a gap is inserted and never replaced. The failure scenario is in its own patch (0015) for traceability. This patch (of 21): The vma iterator may be left pointing to the newly created vma. This happens when inserting the new vma at the end of the old vma (!new_below). The incorrect position in the vma iterator is not exposed currently since the vma iterator is repositioned in the munmap path and is not reused in any of the other paths. This has limited impact in the current code, but is required for future changes. Link: https://lkml.kernel.org/r/20240830040101.822209-2-Liam.Howlett@oracle.com Fixes: b2b3b886 ("mm: don't use __vma_adjust() in __split_vma()") Signed-off-by:
Lorenzo Stoakes <lstoakes@gmail.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mark Brown <broonie@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Signed-off-by:
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Mike Yuan authored
As discussed in [1], zswap-related settings natually lose their effect when zswap is disabled, specifically zswap.writeback here. Be explicit about this behavior. [1] https://lore.kernel.org/linux-kernel/CAKEwX=Mhbwhh-=xxCU-RjMXS_n=RpV3Gtznb2m_3JgL+jzz++g@mail.gmail.com/ [akpm@linux-foundation.org: fix/simplify text] Link: https://lkml.kernel.org/r/20240823162506.12117-3-me@yhndnzj.comSigned-off-by:
Mike Yuan <me@yhndnzj.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by:
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Mike Yuan authored
Ensure that zswap.writeback check goes up the cgroup tree, i.e. is hierarchical. Create a subcgroup which has zswap.writeback set to 1, and the upper hierarchy's restrictions shall apply. Link: https://lkml.kernel.org/r/20240823162506.12117-2-me@yhndnzj.comSigned-off-by:
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Usama Arif authored
With an earlier commit to handle zero-filled pages in swap directly, and with only 1% of the same-filled pages being non-zero, zswap no longer needs to handle same-filled pages and can just work on compressed pages. Link: https://lkml.kernel.org/r/20240823190545.979059-3-usamaarif642@gmail.comSigned-off-by:
Usama Arif <usamaarif642@gmail.com> Reviewed-by:
Chengming Zhou <chengming.zhou@linux.dev> Acked-by:
Yosry Ahmed <yosryahmed@google.com> Reviewed-by:
Nhat Pham <nphamcs@gmail.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by:
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Usama Arif authored
Patch series "mm: store zero pages to be swapped out in a bitmap", v8. As shown in the patch series that introduced the zswap same-filled optimization [1], 10-20% of the pages stored in zswap are same-filled. This is also observed across Meta's server fleet. By using VM counters in swap_writepage (not included in this patchseries) it was found that less than 1% of the same-filled pages to be swapped out are non-zero pages. For conventional swap setup (without zswap), rather than reading/writing these pages to flash resulting in increased I/O and flash wear, a bitmap can be used to mark these pages as zero at write time, and the pages can be filled at read time if the bit corresponding to the page is set. When using zswap with swap, this also means that a zswap_entry does not need to be allocated for zero filled pages resulting in memory savings which would offset the memory used for the bitmap. A similar attempt was made earlier in [2] where zswap would only track zero-filled pages instead of same-filled. This patchseries adds zero-filled pages optimization to swap (hence it can be used even if zswap is disabled) and removes the same-filled code from zswap (as only 1% of the same-filled pages are non-zero), simplifying code. [1] https://lore.kernel.org/all/20171018104832epcms5p1b2232e2236258de3d03d1344dde9fce0@epcms5p1/ [2] https://lore.kernel.org/lkml/20240325235018.2028408-1-yosryahmed@google.com/ This patch (of 2): Approximately 10-20% of pages to be swapped out are zero pages [1]. Rather than reading/writing these pages to flash resulting in increased I/O and flash wear, a bitmap can be used to mark these pages as zero at write time, and the pages can be filled at read time if the bit corresponding to the page is set. With this patch, NVMe writes in Meta server fleet decreased by almost 10% with conventional swap setup (zswap disabled). [1] https://lore.kernel.org/all/20171018104832epcms5p1b2232e2236258de3d03d1344dde9fce0@epcms5p1/ Link: https://lkml.kernel.org/r/20240823190545.979059-1-usamaarif642@gmail.com Link: https://lkml.kernel.org/r/20240823190545.979059-2-usamaarif642@gmail.comSigned-off-by:
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Zhongkun He authored
should_reclaim_retry() is not ALLOC_CPUSET aware and that means that it considers reclaimability of NUMA nodes which are outside of the cpuset. If other nodes have a lot of reclaimable memory then should_reclaim_retry would instruct page allocator to retry even though there is no memory reclaimable on the cpuset nodemask. This is not really a huge problem because the number of retries without any reclaim progress is bound but it could be certainly improved. This is a cold path so this shouldn't really have a measurable impact on performance on most workloads. 1.Test step and the machines. ------------ root@vm:/sys/fs/cgroup/test# numactl -H | grep size node 0 size: 9477 MB node 1 size: 10079 MB node 2 size: 10079 MB node 3 size: 10078 MB root@vm:/sys/fs/cgroup/test# cat cpuset.mems 2 root@vm:/sys/fs/cgroup/test# stress --vm 1 --vm-bytes 12g --vm-keep stress: info: [33430] dispatching hogs: 0 cpu, 0 io, 1 vm, 0 hdd stress: FAIL: [33430] (425) <-- worker 33431 got signal 9 stress: WARN: [33430] (427) now reaping child worker processes stress: FAIL: [33430] (461) failed run completed in 2s 2. reclaim_retry_zone info: We can only alloc pages from node=2, but the reclaim_retry_zone is node=0 and return true. root@vm:/sys/kernel/debug/tracing# cat trace stress-33431 [001] ..... 13223.617311: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=1 wmark_check=1 stress-33431 [001] ..... 13223.617682: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=2 wmark_check=1 stress-33431 [001] ..... 13223.618103: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=3 wmark_check=1 stress-33431 [001] ..... 13223.618454: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=4 wmark_check=1 stress-33431 [001] ..... 13223.618770: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=5 wmark_check=1 stress-33431 [001] ..... 13223.619150: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=6 wmark_check=1 stress-33431 [001] ..... 13223.619510: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=7 wmark_check=1 stress-33431 [001] ..... 13223.619850: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=8 wmark_check=1 stress-33431 [001] ..... 13223.620171: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=9 wmark_check=1 stress-33431 [001] ..... 13223.620533: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=10 wmark_check=1 stress-33431 [001] ..... 13223.620894: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=11 wmark_check=1 stress-33431 [001] ..... 13223.621224: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=12 wmark_check=1 stress-33431 [001] ..... 13223.621551: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=13 wmark_check=1 stress-33431 [001] ..... 13223.621847: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=14 wmark_check=1 stress-33431 [001] ..... 13223.622200: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=15 wmark_check=1 stress-33431 [001] ..... 13223.622580: reclaim_retry_zone: node=0 zone=Normal order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=16 wmark_check=1 With this patch, we can check the right node and get less retry in __alloc_pages_slowpath() because there is nothing to do. Link: https://lkml.kernel.org/r/20240822092612.3209286-1-hezhongkun.hzk@bytedance.comSigned-off-by:Zhongkun He <hezhongkun.hzk@bytedance.com> Suggested-by:
Michal Hocko <mhocko@suse.com> Acked-by:
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Johannes Weiner authored
We've been noticing a trend of significant lock contention in the swap subsystem as core counts have been increasing in our fleet. It turns out that our swapfiles on btrfs on flash were in fact using the old swap code for rotational storage. This turns out to be a detection issue in the swapon sequence: btrfs sets si->bdev during swap activation, which currently happens *after* swapon's SSD detection and cluster setup. Thus, none of the SSD optimizations and cluster lock splitting are enabled for btrfs swap. Rearrange the swapon sequence so that filesystem activation happens *before* determining swap behavior based on the backing device. Afterwards, the nonrotational drive is detected correctly: - Adding 2097148k swap on /mnt/swapfile. Priority:-3 extents:1 across:2097148k + Adding 2097148k swap on /mnt/swapfile. Priority:-3 extents:1 across:2097148k SS Link: https://lkml.kernel.org/r/20240822112707.351844-1-hannes@cmpxchg.orgSigned-off-by:
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Yuesong Li authored
Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using the existing helper folio_next_index(). Link: https://lkml.kernel.org/r/20240821063112.4053157-1-liyuesong@vivo.comSigned-off-by:
Yuesong Li <liyuesong@vivo.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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David Hildenbrand authored
Currently, running the charge_reserved_hugetlb.sh selftest we can sometimes observe something like: $ ./charge_reserved_hugetlb.sh -cgroup-v2 ... write_result is 0 After write: hugetlb_usage=0 reserved_usage=10485760 killing write_to_hugetlbfs Received 2. Deleting the memory Detach failure: Invalid argument umount: /mnt/huge: target is busy. Both cases are issues in the test. While the unmount error seems to be racy, it will make the test fail: $ ./run_vmtests.sh -t hugetlb ... # [FAIL] not ok 10 charge_reserved_hugetlb.sh -cgroup-v2 # exit=32 The issue is that we are not waiting for the write_to_hugetlbfs process to quit. So it might still have a hugetlbfs file open, about which umount is not happy. Fix that by making "killall" wait for the process to quit. The other error ("Detach failure: Invalid argument") does not seem to result in a test error, but is misleading. Turns out write_to_hugetlbfs.c unconditionally tries to cleanup using shmdt(), even when we only mmap()'ed a hugetlb file. Even worse, shmaddr is never even set for the SHM case. Fix that as well. With this change it seems to work as expected. Link: https://lkml.kernel.org/r/20240821123115.2068812-1-david@redhat.com Fixes: 29750f71 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests") Signed-off-by:David Hildenbrand <david@redhat.com> Reported-by:
Mario Casquero <mcasquer@redhat.com> Reviewed-by:
Mina Almasry <almasrymina@google.com> Tested-by:
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Matthew Wilcox (Oracle) authored
Convert x86 to use PG_arch_2 instead of PG_uncached and remove PG_uncached. Link: https://lkml.kernel.org/r/20240821193445.2294269-11-willy@infradead.orgSigned-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
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Matthew Wilcox (Oracle) authored
This flag has similar constraints to PG_owner_priv_1 -- it is ignored by core code, and is entirely for the use of the code which allocated the folio. Since the pagecache does not use it, individual filesystems can use it. The bufferhead code does use it, so filesystems which use the buffer cache must not use it for another purpose. Link: https://lkml.kernel.org/r/20240821193445.2294269-10-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
This function has no more callers, except folio_has_private(). Combine the two functions. Link: https://lkml.kernel.org/r/20240821193445.2294269-9-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
While there are many aliases for this flag, nobody actually uses the *PageOwnerPriv1() nor folio_*_owner_priv_1() accessors. Remove them. Link: https://lkml.kernel.org/r/20240821193445.2294269-8-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
This flag is now only used on folios, so we can remove all the page accessors. Link: https://lkml.kernel.org/r/20240821193445.2294269-7-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
There is only one caller of PageUnevictable() left; convert it to call folio_test_unevictable() and remove all the page accessors. Link: https://lkml.kernel.org/r/20240821193445.2294269-6-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
This flag is now only used on folios, so we can remove all the page accessors and reword the comments that refer to them. Link: https://lkml.kernel.org/r/20240821193445.2294269-5-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
This flag is now only used on folios, so we can remove all the page accessors. Link: https://lkml.kernel.org/r/20240821193445.2294269-4-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
This flag is now only used on folios, so we can remove all the page accessors. Link: https://lkml.kernel.org/r/20240821193445.2294269-3-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Patch series "Simplify the page flags a little". In the course of our folio conversions, we have made many page flags only used on folios, so we can now remove the page-based accessors. This should cut down compile time a little, and prevent new users from cropping up. There is more that could be done in this area, but it would produce merge conflicts, so I'll sit on those patches until next merge window. We now have line of sight to removing PG_private_2 and PG_private. This patch (of 10): This flag is now only used on folios, so we can remove all the page accessors. [akpm@linux-foundation.org: fix arch/powerpc/mm/pgtable-frag.c] Link: https://lkml.kernel.org/r/20240821193445.2294269-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240821193445.2294269-2-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Now that we have an extra 8 bits, we don't need to limit ourselves to supporting a 64KiB page size. I'm sure both Hexagon users are grateful, but it does reduce complexity a little. We can also remove reset_first_obj_offset() as calling __ClearPageZsmalloc() will now reset all 32 bits of page_type. Link: https://lkml.kernel.org/r/20240821173914.2270383-5-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
By using a few values in the top byte, users of page_type can store up to 24 bits of additional data in page_type. It also reduces the code size as (with replacement of READ_ONCE() with data_race()), the kernel can check just a single byte. eg: ffffffff811e3a79: 8b 47 30 mov 0x30(%rdi),%eax ffffffff811e3a7c: 55 push %rbp ffffffff811e3a7d: 48 89 e5 mov %rsp,%rbp ffffffff811e3a80: 25 00 00 00 82 and $0x82000000,%eax ffffffff811e3a85: 3d 00 00 00 80 cmp $0x80000000,%eax ffffffff811e3a8a: 74 4d je ffffffff811e3ad9 <folio_mapping+0x69> becomes: ffffffff811e3a69: 80 7f 33 f5 cmpb $0xf5,0x33(%rdi) ffffffff811e3a6d: 55 push %rbp ffffffff811e3a6e: 48 89 e5 mov %rsp,%rbp ffffffff811e3a71: 74 4d je ffffffff811e3ac0 <folio_mapping+0x60> replacing three instructions with one. [wangkefeng.wang@huawei.com: fix ubsan warnings] Link: https://lkml.kernel.org/r/2d19c48a-c550-4345-bf36-d05cd303c5de@huawei.com Link: https://lkml.kernel.org/r/20240821173914.2270383-4-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Resolve the awkward "and add one to this opaque constant" test into a self-documenting inline function. Link: https://lkml.kernel.org/r/20240821173914.2270383-3-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Patch series "Increase the number of bits available in page_type". Kent wants more than 16 bits in page_type, so I resurrected this old patch and expanded it a bit. It's a bit more efficient than our current scheme (1 4-byte insn vs 3 insns of 13 bytes total) to test a single page type. This patch (of 4): An upcoming patch will convert page type from being a bitfield to a single byte, so we will not be able to use %pG to print the page type any more. The printing of the symbolic name will be restored in that patch. Link: https://lkml.kernel.org/r/20240821173914.2270383-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240821173914.2270383-2-willy@infradead.orgSigned-off-by:
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Pedro Falcato authored
Add more mseal traversal tests across VMAs, where we could possibly screw up sealing checks. These test more across-vma traversal for mprotect, munmap and madvise. Particularly, we test for the case where a regular VMA is followed by a sealed VMA. [akpm@linux-foundation.org: remove incorrect comment, per review] [akpm@linux-foundation.org: remove the correct comment, per Pedro] [pedro.falcato@gmail.com: fix mseal's length] Link: https://lkml.kernel.org/r/vc4czyuemmu3kylqb4ctaga6y5yvondlyabimx6jvljlw2fkea@djawlllf45xa Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-7-d8d2e037df30@gmail.comSigned-off-by:
Pedro Falcato <pedro.falcato@gmail.com> Reviewed-by:
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Pedro Falcato authored
With no more users in the tree, we can finally remove can_modify_mm(). Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-6-d8d2e037df30@gmail.comSigned-off-by:
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Pedro Falcato authored
Replace can_modify_mm_madv() with a single vma variant, and associated checks in madvise. While we're at it, also invert the order of checks in: if (unlikely(is_ro_anon(vma) && !can_modify_vma(vma)) Checking if we can modify the vma itself (through vm_flags) is certainly cheaper than is_ro_anon() due to arch_vma_access_permitted() looking at e.g pkeys registers (with extra branches) in some architectures. This patch allows for partial madvise success when finding a sealed VMA, which historically has been allowed in Linux. Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-5-d8d2e037df30@gmail.comSigned-off-by:
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Pedro Falcato authored
Delegate all can_modify checks to the proper places. Unmap checks are done in do_unmap (et al). The source VMA check is done purposefully before unmapping, to keep the original mseal semantics. Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-4-d8d2e037df30@gmail.comSigned-off-by:
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