- 04 Sep, 2024 3 commits
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Chris Li authored
Previously the SSD and HDD share the same swap_map scan loop in scan_swap_map_slots(). This function is complex and hard to flow the execution flow. scan_swap_map_try_ssd_cluster() can already do most of the heavy lifting to locate the candidate swap range in the cluster. However it needs to go back to scan_swap_map_slots() to check conflict and then perform the allocation. When scan_swap_map_try_ssd_cluster() failed, it still depended on the scan_swap_map_slots() to do brute force scanning of the swap_map. When the swapfile is large and almost full, it will take some CPU time to go through the swap_map array. Get rid of the cluster allocation dependency on the swap_map scan loop in scan_swap_map_slots(). Streamline the cluster allocation code path. No more conflict checks. For order 0 swap entry, when run out of free and nonfull list. It will allocate from the higher order nonfull cluster list. Users should see less CPU time spent on searching the free swap slot when swapfile is almost full. [ryncsn@gmail.com: fix array-bounds error with CONFIG_THP_SWAP=n] Link: https://lkml.kernel.org/r/CAMgjq7Bz0DY+rY0XgCoH7-Q=uHLdo3omi8kUr4ePDweNyofsbQ@mail.gmail.com Link: https://lkml.kernel.org/r/20240730-swap-allocator-v5-3-cb9c148b9297@kernel.orgSigned-off-by:
Chris Li <chrisl@kernel.org> Signed-off-by:
Kairui Song <kasong@tencent.com> Reported-by:
Barry Song <21cnbao@gmail.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Chris Li authored
Track the nonfull cluster as well as the empty cluster on lists. Each order has one nonfull cluster list. The cluster will remember which order it was used during new cluster allocation. When the cluster has free entry, add to the nonfull[order] list. When the free cluster list is empty, also allocate from the nonempty list of that order. This improves the mTHP swap allocation success rate. There are limitations if the distribution of numbers of different orders of mTHP changes a lot. e.g. there are a lot of nonfull cluster assign to order A while later time there are a lot of order B allocation while very little allocation in order A. Currently the cluster used by order A will not reused by order B unless the cluster is 100% empty. Link: https://lkml.kernel.org/r/20240730-swap-allocator-v5-2-cb9c148b9297@kernel.orgSigned-off-by:
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Chris Li authored
Patch series "mm: swap: mTHP swap allocator base on swap cluster order", v5. This is the short term solutions "swap cluster order" listed in my "Swap Abstraction" discussion slice 8 in the recent LSF/MM conference. When commit 845982eb "mm: swap: allow storage of all mTHP orders" is introduced, it only allocates the mTHP swap entries from the new empty cluster list. It has a fragmentation issue reported by Barry. https://lore.kernel.org/all/CAGsJ_4zAcJkuW016Cfi6wicRr8N9X+GJJhgMQdSMp+Ah+NSgNQ@mail.gmail.com/ The reason is that all the empty clusters have been exhausted while there are plenty of free swap entries in the cluster that are not 100% free. Remember the swap allocation order in the cluster. Keep track of the per order non full cluster list for later allocation. This series gives the swap SSD allocation a new separate code path from the HDD allocation. The new allocator use cluster list only and do not global scan swap_map[] without lock any more. This streamline the swap allocation for SSD. The code matches the execution flow much better. User impact: For users that allocate and free mix order mTHP swapping, It greatly improves the success rate of the mTHP swap allocation after the initial phase. It also performs faster when the swapfile is close to full, because the allocator can get the non full cluster from a list rather than scanning a lot of swap_map entries. With Barry's mthp test program V2: Without: $ ./thp_swap_allocator_test -a Iteration 1: swpout inc: 32, swpout fallback inc: 192, Fallback percentage: 85.71% Iteration 2: swpout inc: 0, swpout fallback inc: 231, Fallback percentage: 100.00% Iteration 3: swpout inc: 0, swpout fallback inc: 227, Fallback percentage: 100.00% ... Iteration 98: swpout inc: 0, swpout fallback inc: 224, Fallback percentage: 100.00% Iteration 99: swpout inc: 0, swpout fallback inc: 215, Fallback percentage: 100.00% Iteration 100: swpout inc: 0, swpout fallback inc: 222, Fallback percentage: 100.00% $ ./thp_swap_allocator_test -a -s Iteration 1: swpout inc: 0, swpout fallback inc: 224, Fallback percentage: 100.00% Iteration 2: swpout inc: 0, swpout fallback inc: 218, Fallback percentage: 100.00% Iteration 3: swpout inc: 0, swpout fallback inc: 222, Fallback percentage: 100.00% .. Iteration 98: swpout inc: 0, swpout fallback inc: 228, Fallback percentage: 100.00% Iteration 99: swpout inc: 0, swpout fallback inc: 230, Fallback percentage: 100.00% Iteration 100: swpout inc: 0, swpout fallback inc: 229, Fallback percentage: 100.00% $ ./thp_swap_allocator_test -s Iteration 1: swpout inc: 0, swpout fallback inc: 224, Fallback percentage: 100.00% Iteration 2: swpout inc: 0, swpout fallback inc: 218, Fallback percentage: 100.00% Iteration 3: swpout inc: 0, swpout fallback inc: 222, Fallback percentage: 100.00% .. Iteration 98: swpout inc: 0, swpout fallback inc: 228, Fallback percentage: 100.00% Iteration 99: swpout inc: 0, swpout fallback inc: 230, Fallback percentage: 100.00% Iteration 100: swpout inc: 0, swpout fallback inc: 229, Fallback percentage: 100.00% $ ./thp_swap_allocator_test Iteration 1: swpout inc: 0, swpout fallback inc: 224, Fallback percentage: 100.00% Iteration 2: swpout inc: 0, swpout fallback inc: 218, Fallback percentage: 100.00% Iteration 3: swpout inc: 0, swpout fallback inc: 222, Fallback percentage: 100.00% .. Iteration 98: swpout inc: 0, swpout fallback inc: 228, Fallback percentage: 100.00% Iteration 99: swpout inc: 0, swpout fallback inc: 230, Fallback percentage: 100.00% Iteration 100: swpout inc: 0, swpout fallback inc: 229, Fallback percentage: 100.00% With: # with all 0.00% filter out $ ./thp_swap_allocator_test -a | grep -v "0.00%" $ # all result are 0.00% $ ./thp_swap_allocator_test -a -s | grep -v "0.00%" ./thp_swap_allocator_test -a -s | grep -v "0.00%" Iteration 14: swpout inc: 223, swpout fallback inc: 3, Fallback percentage: 1.33% Iteration 19: swpout inc: 219, swpout fallback inc: 7, Fallback percentage: 3.10% Iteration 28: swpout inc: 225, swpout fallback inc: 1, Fallback percentage: 0.44% Iteration 29: swpout inc: 227, swpout fallback inc: 1, Fallback percentage: 0.44% Iteration 34: swpout inc: 220, swpout fallback inc: 8, Fallback percentage: 3.51% Iteration 35: swpout inc: 222, swpout fallback inc: 11, Fallback percentage: 4.72% Iteration 38: swpout inc: 217, swpout fallback inc: 4, Fallback percentage: 1.81% Iteration 40: swpout inc: 222, swpout fallback inc: 6, Fallback percentage: 2.63% Iteration 42: swpout inc: 221, swpout fallback inc: 2, Fallback percentage: 0.90% Iteration 43: swpout inc: 215, swpout fallback inc: 7, Fallback percentage: 3.15% Iteration 47: swpout inc: 226, swpout fallback inc: 2, Fallback percentage: 0.88% Iteration 49: swpout inc: 217, swpout fallback inc: 1, Fallback percentage: 0.46% Iteration 52: swpout inc: 221, swpout fallback inc: 8, Fallback percentage: 3.49% Iteration 56: swpout inc: 224, swpout fallback inc: 4, Fallback percentage: 1.75% Iteration 58: swpout inc: 214, swpout fallback inc: 5, Fallback percentage: 2.28% Iteration 62: swpout inc: 220, swpout fallback inc: 3, Fallback percentage: 1.35% Iteration 64: swpout inc: 224, swpout fallback inc: 1, Fallback percentage: 0.44% Iteration 67: swpout inc: 221, swpout fallback inc: 1, Fallback percentage: 0.45% Iteration 75: swpout inc: 220, swpout fallback inc: 9, Fallback percentage: 3.93% Iteration 82: swpout inc: 227, swpout fallback inc: 1, Fallback percentage: 0.44% Iteration 86: swpout inc: 211, swpout fallback inc: 12, Fallback percentage: 5.38% Iteration 89: swpout inc: 226, swpout fallback inc: 2, Fallback percentage: 0.88% Iteration 93: swpout inc: 220, swpout fallback inc: 1, Fallback percentage: 0.45% Iteration 94: swpout inc: 224, swpout fallback inc: 1, Fallback percentage: 0.44% Iteration 96: swpout inc: 221, swpout fallback inc: 6, Fallback percentage: 2.64% Iteration 98: swpout inc: 227, swpout fallback inc: 1, Fallback percentage: 0.44% Iteration 99: swpout inc: 227, swpout fallback inc: 3, Fallback percentage: 1.30% $ ./thp_swap_allocator_test ./thp_swap_allocator_test Iteration 1: swpout inc: 233, swpout fallback inc: 0, Fallback percentage: 0.00% Iteration 2: swpout inc: 131, swpout fallback inc: 101, Fallback percentage: 43.53% Iteration 3: swpout inc: 71, swpout fallback inc: 155, Fallback percentage: 68.58% Iteration 4: swpout inc: 55, swpout fallback inc: 168, Fallback percentage: 75.34% Iteration 5: swpout inc: 35, swpout fallback inc: 191, Fallback percentage: 84.51% Iteration 6: swpout inc: 25, swpout fallback inc: 199, Fallback percentage: 88.84% Iteration 7: swpout inc: 23, swpout fallback inc: 205, Fallback percentage: 89.91% Iteration 8: swpout inc: 9, swpout fallback inc: 219, Fallback percentage: 96.05% Iteration 9: swpout inc: 13, swpout fallback inc: 213, Fallback percentage: 94.25% Iteration 10: swpout inc: 12, swpout fallback inc: 216, Fallback percentage: 94.74% Iteration 11: swpout inc: 16, swpout fallback inc: 213, Fallback percentage: 93.01% Iteration 12: swpout inc: 10, swpout fallback inc: 210, Fallback percentage: 95.45% Iteration 13: swpout inc: 16, swpout fallback inc: 212, Fallback percentage: 92.98% Iteration 14: swpout inc: 12, swpout fallback inc: 212, Fallback percentage: 94.64% Iteration 15: swpout inc: 15, swpout fallback inc: 211, Fallback percentage: 93.36% Iteration 16: swpout inc: 15, swpout fallback inc: 200, Fallback percentage: 93.02% Iteration 17: swpout inc: 9, swpout fallback inc: 220, Fallback percentage: 96.07% $ ./thp_swap_allocator_test -s ./thp_swap_allocator_test -s Iteration 1: swpout inc: 233, swpout fallback inc: 0, Fallback percentage: 0.00% Iteration 2: swpout inc: 97, swpout fallback inc: 135, Fallback percentage: 58.19% Iteration 3: swpout inc: 42, swpout fallback inc: 192, Fallback percentage: 82.05% Iteration 4: swpout inc: 19, swpout fallback inc: 214, Fallback percentage: 91.85% Iteration 5: swpout inc: 12, swpout fallback inc: 213, Fallback percentage: 94.67% Iteration 6: swpout inc: 11, swpout fallback inc: 217, Fallback percentage: 95.18% Iteration 7: swpout inc: 9, swpout fallback inc: 214, Fallback percentage: 95.96% Iteration 8: swpout inc: 8, swpout fallback inc: 213, Fallback percentage: 96.38% Iteration 9: swpout inc: 2, swpout fallback inc: 223, Fallback percentage: 99.11% Iteration 10: swpout inc: 2, swpout fallback inc: 228, Fallback percentage: 99.13% Iteration 11: swpout inc: 4, swpout fallback inc: 214, Fallback percentage: 98.17% Iteration 12: swpout inc: 5, swpout fallback inc: 226, Fallback percentage: 97.84% Iteration 13: swpout inc: 3, swpout fallback inc: 212, Fallback percentage: 98.60% Iteration 14: swpout inc: 0, swpout fallback inc: 222, Fallback percentage: 100.00% Iteration 15: swpout inc: 3, swpout fallback inc: 222, Fallback percentage: 98.67% Iteration 16: swpout inc: 4, swpout fallback inc: 223, Fallback percentage: 98.24% ========= Kernel compile under tmpfs with cgroup memory.max = 470M. 12 core 24 hyperthreading, 32 jobs. 10 Run each group SSD swap 10 runs average, 20G swap partition: With: user 2929.064 system 1479.381 : 1376.89 1398.22 1444.64 1477.39 1479.04 1497.27 1504.47 1531.4 1532.92 1551.57 real 1441.324 Without: user 2910.872 system 1482.732 : 1440.01 1451.4 1462.01 1467.47 1467.51 1469.3 1470.19 1496.32 1544.1 1559.01 real 1580.822 Two zram swap: zram0 3.0G zram1 20G. The idea is forcing the zram0 almost full then overflow to zram1: With: user 4320.301 system 4272.403 : 4236.24 4262.81 4264.75 4269.13 4269.44 4273.06 4279.85 4285.98 4289.64 4293.13 real 431.759 Without user 4301.393 system 4387.672 : 4374.47 4378.3 4380.95 4382.84 4383.06 4388.05 4389.76 4397.16 4398.23 4403.9 real 433.979 ------ more test result from Kaiui ---------- Test with build linux kernel using a 4G ZRAM, 1G memory.max limit on top of shmem: System info: 32 Core AMD Zen2, 64G total memory. Test 3 times using only 4K pages: ================================= With: ----- 1838.74user 2411.21system 2:37.86elapsed 2692%CPU (0avgtext+0avgdata 847060maxresident)k 1839.86user 2465.77system 2:39.35elapsed 2701%CPU (0avgtext+0avgdata 847060maxresident)k 1840.26user 2454.68system 2:39.43elapsed 2693%CPU (0avgtext+0avgdata 847060maxresident)k Summary (~4.6% improment of system time): User: 1839.62 System: 2443.89: 2465.77 2454.68 2411.21 Real: 158.88 Without: -------- 1837.99user 2575.95system 2:43.09elapsed 2706%CPU (0avgtext+0avgdata 846520maxresident)k 1838.32user 2555.15system 2:42.52elapsed 2709%CPU (0avgtext+0avgdata 846520maxresident)k 1843.02user 2561.55system 2:43.35elapsed 2702%CPU (0avgtext+0avgdata 846520maxresident)k Summary: User: 1839.78 System: 2564.22: 2575.95 2555.15 2561.55 Real: 162.99 Test 5 times using enabled all mTHP pages: ========================================== With: ----- 1796.44user 2937.33system 2:59.09elapsed 2643%CPU (0avgtext+0avgdata 846936maxresident)k 1802.55user 3002.32system 2:54.68elapsed 2750%CPU (0avgtext+0avgdata 847072maxresident)k 1806.59user 2986.53system 2:55.17elapsed 2736%CPU (0avgtext+0avgdata 847092maxresident)k 1803.27user 2982.40system 2:54.49elapsed 2742%CPU (0avgtext+0avgdata 846796maxresident)k 1807.43user 3036.08system 2:56.06elapsed 2751%CPU (0avgtext+0avgdata 846488maxresident)k Summary (~8.4% improvement of system time): User: 1803.25 System: 2988.93: 2937.33 3002.32 2986.53 2982.40 3036.08 Real: 175.90 mTHP swapout status: /sys/kernel/mm/transparent_hugepage/hugepages-32kB/stats/swpout:347721 /sys/kernel/mm/transparent_hugepage/hugepages-32kB/stats/swpout_fallback:3110 /sys/kernel/mm/transparent_hugepage/hugepages-512kB/stats/swpout:3365 /sys/kernel/mm/transparent_hugepage/hugepages-512kB/stats/swpout_fallback:8269 /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/stats/swpout:24 /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/stats/swpout_fallback:3341 /sys/kernel/mm/transparent_hugepage/hugepages-1024kB/stats/swpout:145 /sys/kernel/mm/transparent_hugepage/hugepages-1024kB/stats/swpout_fallback:5038 /sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpout:322737 /sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpout_fallback:36808 /sys/kernel/mm/transparent_hugepage/hugepages-16kB/stats/swpout:380455 /sys/kernel/mm/transparent_hugepage/hugepages-16kB/stats/swpout_fallback:1010 /sys/kernel/mm/transparent_hugepage/hugepages-256kB/stats/swpout:24973 /sys/kernel/mm/transparent_hugepage/hugepages-256kB/stats/swpout_fallback:13223 /sys/kernel/mm/transparent_hugepage/hugepages-128kB/stats/swpout:197348 /sys/kernel/mm/transparent_hugepage/hugepages-128kB/stats/swpout_fallback:80541 Without: -------- 1794.41user 3151.29system 3:05.97elapsed 2659%CPU (0avgtext+0avgdata 846704maxresident)k 1810.27user 3304.48system 3:05.38elapsed 2759%CPU (0avgtext+0avgdata 846636maxresident)k 1809.84user 3254.85system 3:03.83elapsed 2755%CPU (0avgtext+0avgdata 846952maxresident)k 1813.54user 3259.56system 3:04.28elapsed 2752%CPU (0avgtext+0avgdata 846848maxresident)k 1829.97user 3338.40system 3:07.32elapsed 2759%CPU (0avgtext+0avgdata 847024maxresident)k Summary: User: 1811.61 System: 3261.72 : 3151.29 3304.48 3254.85 3259.56 3338.40 Real: 185.356 mTHP swapout status: hugepages-32kB/stats/swpout:35630 hugepages-32kB/stats/swpout_fallback:1809908 hugepages-512kB/stats/swpout:523 hugepages-512kB/stats/swpout_fallback:55235 hugepages-2048kB/stats/swpout:53 hugepages-2048kB/stats/swpout_fallback:17264 hugepages-1024kB/stats/swpout:85 hugepages-1024kB/stats/swpout_fallback:24979 hugepages-64kB/stats/swpout:30117 hugepages-64kB/stats/swpout_fallback:1825399 hugepages-16kB/stats/swpout:42775 hugepages-16kB/stats/swpout_fallback:1951123 hugepages-256kB/stats/swpout:2326 hugepages-256kB/stats/swpout_fallback:170165 hugepages-128kB/stats/swpout:17925 hugepages-128kB/stats/swpout_fallback:1309757 This patch (of 9): Previously, the swap cluster used a cluster index as a pointer to construct a custom single link list type "swap_cluster_list". The next cluster pointer is shared with the cluster->count. It prevents puting the non free cluster into a list. Change the cluster to use the standard double link list instead. This allows tracing the nonfull cluster in the follow up patch. That way, it is faster to get to the nonfull cluster of that order. Remove the cluster getter/setter for accessing the cluster struct member. The list operation is protected by the swap_info_struct->lock. Change cluster code to use "struct swap_cluster_info *" to reference the cluster rather than by using index. That is more consistent with the list manipulation. It avoids the repeat adding index to the cluser_info. The code is easier to understand. Remove the cluster next pointer is NULL flag, the double link list can handle the empty list pretty well. The "swap_cluster_info" struct is two pointer bigger, because 512 swap entries share one swap_cluster_info struct, it has very little impact on the average memory usage per swap entry. For 1TB swapfile, the swap cluster data structure increases from 8MB to 24MB. Other than the list conversion, there is no real function change in this patch. Link: https://lkml.kernel.org/r/20240730-swap-allocator-v5-0-cb9c148b9297@kernel.org Link: https://lkml.kernel.org/r/20240730-swap-allocator-v5-1-cb9c148b9297@kernel.orgSigned-off-by:
"Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by:
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- 02 Sep, 2024 37 commits
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Shakeel Butt authored
The pressure_level in memcg v1 provides memory pressure notifications to the user space. At the moment it provides notifications for three levels of memory pressure i.e. low, medium and critical, which are defined based on internal memory reclaim implementation details. More specifically the ratio of scanned and reclaimed pages during a memory reclaim. However this is not robust as there are workloads with mostly unreclaimable user memory or kernel memory. For v2, the users can use PSI for memory pressure status of the system or the cgroup. Let's start the deprecation process for pressure_level and add warnings to gather the info on how the current users are using this interface and how they can be used to PSI. Link: https://lkml.kernel.org/r/20240814220021.3208384-5-shakeel.butt@linux.devSigned-off-by:
Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by:
T.J. Mercier <tjmercier@google.com> Acked-by:
Michal Hocko <mhocko@suse.com> Acked-by:
Roman Gushchin <roman.gushchin@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by:
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Shakeel Butt authored
The oom_control provides functionality to disable memcg oom-killer, notifications on oom-kill and reading the stats regarding oom-kills. This interface was mainly introduced to provide functionality for userspace oom-killers. However it is not robust enough and only supports OOM handling in the page fault path. For v2, the users can use the combination of memory.events notifications, memory.high and PSI to provide userspace OOM-killing functionality. Actually LMKD in Android and OOMd in systemd and Meta infrastructure already use PSI in combination with other stats to implement userspace OOM-killing. Let's start the deprecation process for v1 and gather the info on how the current users are using this interface and work on providing a more robust functionality in v2. Link: https://lkml.kernel.org/r/20240814220021.3208384-4-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
Memcg v1 provides soft limit functionality for the best effort memory sharing between multiple workloads on a system. It is usually triggered through kswapd and at the moment does not reclaim kernel memory. Memcg v2 provides more straightforward best effort (memory.low) and hard protection (memory.min) functionalities. Let's initiate the deprecation of soft limit from v1 and gather if v2 needs something more to move the existing v1 users to v2 regarding soft limit. Link: https://lkml.kernel.org/r/20240814220021.3208384-3-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
Patch series "memcg: initiate deprecation of v1 features", v2. Start the deprecation process of the memcg v1 features which we discussed during LSFMMBPF 2024 [1]. For now add the warnings to collect the information on how the current users are using these features. Next we will work on providing better alternatives in v2 (if needed) and fully deprecate these features. Link: https://lwn.net/Articles/974575 [1] This patch (of 4): Memcg v1 provides opt-in TCP memory accounting feature. However it is mostly unused due to its performance impact on the network traffic. In v2, the TCP memory is accounted in the regular memory usage and is transparent to the users but they can observe the TCP memory usage through memcg stats. Let's initiate the deprecation process of memcg v1's tcp accounting functionality and add warnings to gather if there are any users and if there are, collect how they are using it and plan to provide them better alternative in v2. Link: https://lkml.kernel.org/r/20240814220021.3208384-1-shakeel.butt@linux.dev Link: https://lkml.kernel.org/r/20240814220021.3208384-2-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
Currently PGPGIN and PGPGOUT are used and exposed in the memcg v1 only code. So, let's put them under CONFIG_MEMCG_V1. Link: https://lkml.kernel.org/r/20240815050453.1298138-8-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
Currently memcg->events_percpu gets allocated on v2 deployments. Let's move the allocation to v1 only codebase. This is not needed in v2. Link: https://lkml.kernel.org/r/20240815050453.1298138-7-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
The functions memcg1_charge_statistics() and memcg1_check_events() are never used outside of v1 source file. So, make them static. Link: https://lkml.kernel.org/r/20240815050453.1298138-6-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
Currently the common code path for charge commit, swapout and batched uncharge are executing v1 only code which is completely useless for the v2 deployments where CONFIG_MEMCG_V1 is disabled. In addition, it is mucking with IRQs which might be slow on some architectures. Let's move all of this code to v1 only code and remove them from v2 only deployments. Link: https://lkml.kernel.org/r/20240815050453.1298138-5-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
There are no callers of mem_cgroup_charge_statistics() in the v2 code base, so move it to the v1 only code and rename it to memcg1_charge_statistics(). Link: https://lkml.kernel.org/r/20240815050453.1298138-4-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
There are no callers of mem_cgroup_event_ratelimit() in the v2 code. Move it to v1 only code and rename it to memcg1_event_ratelimit(). Link: https://lkml.kernel.org/r/20240815050453.1298138-3-shakeel.butt@linux.devSigned-off-by:
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Shakeel Butt authored
Patch series "memcg: further decouple v1 code from v2". Some of the v1 code is still in v2 code base due to v1 fields in the struct memcg_vmstats_percpu. This field decouples those fileds from v2 struct and move all the related code into v1 only code base. This patch (of 7): At the moment struct memcg_vmstats_percpu contains two v1 only fields which consumes memory even when CONFIG_MEMCG_V1 is not enabled. In addition there are v1 only functions accessing them and are in the main memcontrol source file and can not be moved to v1 only source file due to these fields. Let's move these fields into their own struct. Later patches will move the functions accessing them to v1 source file and only allocate these fields when CONFIG_MEMCG_V1 is enabled. Link: https://lkml.kernel.org/r/20240815050453.1298138-1-shakeel.butt@linux.dev Link: https://lkml.kernel.org/r/20240815050453.1298138-2-shakeel.butt@linux.devSigned-off-by:
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Ryan Roberts authored
Add thp_anon= cmdline parameter to allow specifying the default enablement of each supported anon THP size. The parameter accepts the following format and can be provided multiple times to configure each size: thp_anon=<size>,<size>[KMG]:<value>;<size>-<size>[KMG]:<value> An example: thp_anon=16K-64K:always;128K,512K:inherit;256K:madvise;1M-2M:never See Documentation/admin-guide/mm/transhuge.rst for more details. Configuring the defaults at boot time is useful to allow early user space to take advantage of mTHP before its been configured through sysfs. [v-songbaohua@oppo.com: use get_oder() and check size is is_power_of_2] Link: https://lkml.kernel.org/r/20240814224635.43272-1-21cnbao@gmail.com [ryan.roberts@arm.com: some minor cleanup according to David's comments] Link: https://lkml.kernel.org/r/20240820105244.62703-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240814020247.67297-1-21cnbao@gmail.comSigned-off-by:
Ryan Roberts <ryan.roberts@arm.com> Co-developed-by:
Barry Song <v-songbaohua@oppo.com> Signed-off-by:
Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by:
David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lance Yang <ioworker0@gmail.com> Signed-off-by:
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Sidhartha Kumar authored
The return value of various write helper functions are not checked. We can safely change the return type of these functions to be void. Link: https://lkml.kernel.org/r/20240814161944.55347-18-sidhartha.kumar@oracle.comSigned-off-by:
Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by:
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Sidhartha Kumar authored
Users of mas_store_prealloc() enter this function with nodes already preallocated. This means the store type must be already set. We can then remove the call to mas_wr_store_type() and initialize the write state to continue the partial walk that was done when determining the store type. Link: https://lkml.kernel.org/r/20240814161944.55347-17-sidhartha.kumar@oracle.comReviewed-by:
Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by:
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Sidhartha Kumar authored
These sanity checks are now redundant as they are already checked in mas_wr_store_type(). We can remove them from mas_wr_append() and mas_wr_node_store(). Link: https://lkml.kernel.org/r/20240814161944.55347-16-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
These write helper functions are all called from store paths which preallocate enough nodes that will be needed for the write. There is no more need to allocate within the functions themselves. Link: https://lkml.kernel.org/r/20240814161944.55347-15-sidhartha.kumar@oracle.comReviewed-by:
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Sidhartha Kumar authored
Not all users of mas_store() enter with nodes already preallocated. Check for the MA_STATE_PREALLOC flag to decide whether to preallocate nodes within mas_store() rather than relying on future write helper functions to perform the allocations. This allows the write helper functions to be simplified as they do not have to do checks to make sure there are enough allocated nodes to perform the write. Link: https://lkml.kernel.org/r/20240814161944.55347-14-sidhartha.kumar@oracle.comReviewed-by:
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Sidhartha Kumar authored
There are no more users of the function, safely remove it. Link: https://lkml.kernel.org/r/20240814161944.55347-13-sidhartha.kumar@oracle.comReviewed-by:
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Sidhartha Kumar authored
The only callers of mas_commit_b_node() are those with store type of wr_rebalance and wr_split_store. Use mas->store_type to dispatch to the correct helper function. This allows the removal of mas_reuse_node() as it is no longer used. Link: https://lkml.kernel.org/r/20240814161944.55347-12-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
By setting the store type in mas_insert(), we no longer need to use mas_wr_modify() to determine the correct store function to use. Instead, set the store type and call mas_wr_store_entry(). Also, pass in the requested gfp flags to mas_insert() so they can be passed to the call to mas_wr_preallocate(). Link: https://lkml.kernel.org/r/20240814161944.55347-11-sidhartha.kumar@oracle.comReviewed-by:
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Sidhartha Kumar authored
When storing an entry, we can read the store type that was set from a previous partial walk of the tree. Now that the type of store is known, select the correct write helper function to use to complete the store. Also noinline mas_wr_spanning_store() to limit stack frame usage in mas_wr_store_entry() as it allocates a maple_big_node on the stack. Link: https://lkml.kernel.org/r/20240814161944.55347-10-sidhartha.kumar@oracle.comReviewed-by:
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Sidhartha Kumar authored
Knowing the store type of the maple state could be helpful for debugging. Have mas_dump() print mas->store_type. Link: https://lkml.kernel.org/r/20240814161944.55347-9-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Refactor mtree_store_range() to use mas_store_gfp() which will abstract the store, memory allocation, and error handling. Link: https://lkml.kernel.org/r/20240814161944.55347-8-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Use mas_wr_preallocate() in mas_erase() to preallocate enough nodes to complete the erase. Add error handling by skipping the store if the preallocation lead to some error besides no memory. Link: https://lkml.kernel.org/r/20240814161944.55347-7-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Separate call to mas_destroy() from mas_nomem() so we can check for no memory errors without destroying the current maple state in mas_store_gfp(). We then add calls to mas_destroy() to callers of mas_nomem(). Link: https://lkml.kernel.org/r/20240814161944.55347-6-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Introduce mas_wr_store_type() which will set the correct store type based on a walk of the tree. In mas_wr_node_store() the <= min_slots condition is changed to < as if new_end is = to mt_min_slots then there is not enough room. mas_prealloc_calc() is also introduced to abstract the calculation used to determine the number of nodes needed for a store operation. In this change a call to mas_reset() is removed in the error case of mas_prealloc(). This is only needed in the MA_STATE_REBALANCE case of mas_destroy(). We can move the call to mas_reset() directly to mas_destroy(). Also, add a test case to validate the order that we check the store type in is correct. This test models a vma expanding and then shrinking which is part of the boot process. Link: https://lkml.kernel.org/r/20240814161944.55347-5-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Subsequent patches require these definitions to be higher, no functional changes intended. Link: https://lkml.kernel.org/r/20240814161944.55347-4-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Introduce a helper function, mas_wr_prealoc_setup(), that will set up a maple write state in order to start a walk of a maple tree. Link: https://lkml.kernel.org/r/20240814161944.55347-3-sidhartha.kumar@oracle.comSigned-off-by:
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Sidhartha Kumar authored
Patch series "Introduce a store type enum for the Maple tree", v4. ================================ OVERVIEW ================================ This series implements two work items[3]: "aligning mas_store_gfp() with mas_preallocate()" and "enum for store type". mas_store_gfp() is modified to preallocate nodes. This simplies many of the write helper functions by allowing them to use mas_store_gfp() rather than open coding node allocation and error handling. The enum defines the following store types: enum store_type { wr_invalid, wr_new_root, wr_store_root, wr_exact_fit, wr_spanning_store, wr_split_store, wr_rebalance, wr_append, wr_node_store, wr_slot_store, }; In the current maple tree code, a walk down the tree is done in mas_preallocate() to determine the number of nodes needed for this write. After node allocation, mas_wr_store_entry() will perform another walk to determine which write helper function to use to complete the write. Rather than performing the second walk, we can store the type of write in the maple write state during node allocation and read this field to complete the write. Patches 1-16 implement this store type feature. Patch 17 is a cleanup patch to change functions that have unused return types to be void. ================================ RESULTS ================================= Phoronix t-test-1 (Seconds < Lower Is Better) v6.10-rc6 Threads: 1 33.15 Threads: 2 10.81 v6.10-rc6 + this series Threads: 1 32.69 Threads: 2 10.45 Stress-ng mmap 6.10_base store_type_v4 Duration User 2744.65 2769.40 Duration System 10862.69 10817.59 Duration Elapsed 1477.58 1478.35 ================================ TESTING ================================= Testing was done with the maple tree test suite. A new test case is also added to validate the order in which we test for and assign the store type. [1]: https://lore.kernel.org/linux-mm/80926b22-a8d2-9992-eb5e-27e2c99cf460@google.com/T/#m81044feb66765265f8ca7f21e4b4b3725b18780a [2]: https://lore.kernel.org/linux-mm/80926b22-a8d2-9992-eb5e-27e2c99cf460@google.com/T/#mb36c6526486638e82518c0f37a428fb279c84d8a [3]: https://lists.infradead.org/pipermail/maple-tree/2023-December/003098.html This patch (of 17): Add a store_type enum that is stored in ma_state. This will be used to keep track of partial walks of the tree so that subsequent walks can pick up where a previous walk left off. Link: https://lkml.kernel.org/r/20240814161944.55347-1-sidhartha.kumar@oracle.com Link: https://lkml.kernel.org/r/20240814161944.55347-2-sidhartha.kumar@oracle.comSigned-off-by: -
Muchun Song authored
obj_cgroup_memcg() is supposed to safe to prevent the returned memory cgroup from being freed only when the caller is holding the rcu read lock or objcg_lock or cgroup_mutex. It is very easy to ignore thoes conditions when users call some upper APIs which call obj_cgroup_memcg() internally like mem_cgroup_from_slab_obj() (See the link below). So it is better to add lockdep assertion to obj_cgroup_memcg() to find those issues ASAP. Because there is no user of obj_cgroup_memcg() holding objcg_lock to make the returned memory cgroup safe, do not add objcg_lock assertion (We should export objcg_lock if we really want to do). Additionally, this is some internal implementation detail of memcg and should not be accessible outside memcg code. Some users like __mem_cgroup_uncharge() do not care the lifetime of the returned memory cgroup, which just want to know if the folio is charged to a memory cgroup, therefore, they do not need to hold the needed locks. In which case, introduce a new helper folio_memcg_charged() to do this. Compare it to folio_memcg(), it could eliminate a memory access of objcg->memcg for kmem, actually, a really small gain. [songmuchun@bytedance.com: fix split_page_memcg()] Link: https://lkml.kernel.org/r/20240819080415.44964-1-songmuchun@bytedance.com Link: https://lore.kernel.org/all/20240718083607.42068-1-songmuchun@bytedance.com/ Link: https://lkml.kernel.org/r/20240814093415.17634-1-songmuchun@bytedance.comSigned-off-by:
Muchun Song <songmuchun@bytedance.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by:
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Shakeel Butt authored
The Meta prod is seeing large amount of stalls in memcg stats flush from the memcg reclaim code path. At the moment, this specific callsite is doing a synchronous memcg stats flush. The rstat flush is an expensive and time consuming operation, so concurrent relaimers will busywait on the lock potentially for a long time. Actually this issue is not unique to Meta and has been observed by Cloudflare [1] as well. For the Cloudflare case, the stalls were due to contention between kswapd threads running on their 8 numa node machines which does not make sense as rstat flush is global and flush from one kswapd thread should be sufficient for all. Simply replace the synchronous flush with the ratelimited one. One may raise a concern on potentially using 2 sec stale (at worst) stats for heuristics like desirable inactive:active ratio and preferring inactive file pages over anon pages but these specific heuristics do not require very precise stats and also are ignored under severe memory pressure. More specifically for this code path, the stats are needed for two specific heuristics: 1. Deactivate LRUs 2. Cache trim mode The deactivate LRUs heuristic is to maintain a desirable inactive:active ratio of the LRUs. The specific stats needed are WORKINGSET_ACTIVATE* and the hierarchical LRU size. The WORKINGSET_ACTIVATE* is needed to check if there is a refault since last snapshot and the LRU size are needed for the desirable ratio between inactive and active LRUs. See the table below on how the desirable ratio is calculated. /* total target max * memory ratio inactive * ------------------------------------- * 10MB 1 5MB * 100MB 1 50MB * 1GB 3 250MB * 10GB 10 0.9GB * 100GB 31 3GB * 1TB 101 10GB * 10TB 320 32GB */ The desirable ratio only changes at the boundary of 1 GiB, 10 GiB, 100 GiB, 1 TiB and 10 TiB. There is no need for the precise and accurate LRU size information to calculate this ratio. In addition, if deactivation is skipped for some LRU, the kernel will force deactive on the severe memory pressure situation. For the cache trim mode, inactive file LRU size is read and the kernel scales it down based on the reclaim iteration (file >> sc->priority) and only checks if it is zero or not. Again precise information is not needed. This patch has been running on Meta fleet for several months and we have not observed any issues. Please note that MGLRU is not impacted by this issue at all as it avoids rstat flushing completely. Link: https://lore.kernel.org/all/6ee2518b-81dd-4082-bdf5-322883895ffc@kernel.org [1] Link: https://lkml.kernel.org/r/20240813215358.2259750-1-shakeel.butt@linux.devSigned-off-by:
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Linus Torvalds authored
All relevant architectures had already been converted to the new interface (which just has an underscore in front of the name - not very imaginative naming), this just force-converts the stragglers. The modern interface is almost identical to the old one, except instead of the page pointer it takes a "struct vm_special_mapping" that describes the mapping (and contains the page pointer as one member), and it returns the resulting 'vma' instead of just the error code. Getting rid of the old interface also gets rid of some special casing, which had caused problems with the mremap extensions to "struct vm_special_mapping". [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/CAHk-=whvR+z=0=0gzgdfUiK70JTa-=+9vxD-4T=3BagXR6dciA@mail.gmail.comTested-by: Rob Landley <rob@landley.net> # arch/sh/ Link: https://lore.kernel.org/all/20240819195120.GA1113263@thelio-3990X/Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Brian Cain <bcain@quicinc.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Guo Ren <guoren@kernel.org> Cc: Jeff Xu <jeffxu@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Pedro Falcato <pedro.falcato@gmail.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Rob Landley <rob@landley.net> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by:
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Michael Ellerman authored
Linus noticed that the error handling in __arch_setup_additional_pages() fails to clear the mm VDSO pointer if _install_special_mapping() fails. In practice there should be no actual bug, because if there's an error the VDSO pointer is cleared later in arch_setup_additional_pages(). However it's no longer necessary to set the pointer before installing the mapping. Commit c1bab643 ("powerpc/vdso: Move to _install_special_mapping() and remove arch_vma_name()") reworked the code so that the VMA name comes from the vm_special_mapping.name, rather than relying on arch_vma_name(). So rework the code to only set the VDSO pointer once the mappings have been installed correctly, and remove the stale comment. Link: https://lkml.kernel.org/r/20240812082605.743814-4-mpe@ellerman.id.auSigned-off-by:
Michael Ellerman <mpe@ellerman.id.au> Reviewed-by:
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Michael Ellerman authored
Now that powerpc no longer uses arch_unmap() to handle VDSO unmapping, there are no meaningful implementions left. Drop support for it entirely, and update comments which refer to it. Link: https://lkml.kernel.org/r/20240812082605.743814-3-mpe@ellerman.id.auSigned-off-by:
Thomas Gleixner <tglx@linutronix.de> Reviewed-by:
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Michael Ellerman authored
Add a close() callback to the VDSO special mapping to handle unmapping of the VDSO. That will make it possible to remove the arch_unmap() hook entirely in a subsequent patch. Link: https://lkml.kernel.org/r/20240812082605.743814-2-mpe@ellerman.id.auSigned-off-by:
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Michael Ellerman authored
Add an optional close() callback to struct vm_special_mapping. It will be used, by powerpc at least, to handle unmapping of the VDSO. Although support for unmapping the VDSO was initially added for CRIU[1], it is not desirable to guard that support behind CONFIG_CHECKPOINT_RESTORE. There are other known users of unmapping the VDSO which are not related to CRIU, eg. Valgrind [2] and void-ship [3]. The powerpc arch_unmap() hook has been in place for ~9 years, with no ifdef, so there may be other unknown users that have come to rely on unmapping the VDSO. Even if the code was behind an ifdef, major distros enable CHECKPOINT_RESTORE so users may not realise unmapping the VDSO depends on that configuration option. It's also undesirable to have such core mm behaviour behind a relatively obscure CONFIG option. Longer term the unmap behaviour should be standardised across architectures, however that is complicated by the fact the VDSO pointer is stored differently across architectures. There was a previous attempt to unify that handling [4], which could be revived. See [5] for further discussion. [1]: commit 83d3f0e9 ("powerpc/mm: tracking vDSO remap") [2]: https://sourceware.org/git/?p=valgrind.git;a=commit;h=3a004915a2cbdcdebafc1612427576bf3321eef5 [3]: https://github.com/insanitybit/void-ship [4]: https://lore.kernel.org/lkml/20210611180242.711399-17-dima@arista.com/ [5]: https://lore.kernel.org/linuxppc-dev/shiq5v3jrmyi6ncwke7wgl76ojysgbhrchsk32q4lbx2hadqqc@kzyy2igem256 Link: https://lkml.kernel.org/r/20240812082605.743814-1-mpe@ellerman.id.auSigned-off-by:
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Tianchen Ding authored
For kmem_cache with SLAB_TYPESAFE_BY_RCU, the freeing trace stack at calling kmem_cache_free() is more useful. While the following stack is meaningless and provides no help: freed by task 46 on cpu 0 at 656.840729s: rcu_do_batch+0x1ab/0x540 nocb_cb_wait+0x8f/0x260 rcu_nocb_cb_kthread+0x25/0x80 kthread+0xd2/0x100 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1a/0x30 Link: https://lkml.kernel.org/r/20240812095517.2357-1-dtcccc@linux.alibaba.comSigned-off-by:
Tianchen Ding <dtcccc@linux.alibaba.com> Reviewed-by:
Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
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