From 12a5d3955227b0d7e04fb793ccceeb2a1dd275c5 Mon Sep 17 00:00:00 2001 From: Mina Almasry Date: Fri, 2 Dec 2022 14:35:31 -0800 Subject: mm: add nodes= arg to memory.reclaim The nodes= arg instructs the kernel to only scan the given nodes for proactive reclaim. For example use cases, consider a 2 tier memory system: nodes 0,1 -> top tier nodes 2,3 -> second tier $ echo "1m nodes=0" > memory.reclaim This instructs the kernel to attempt to reclaim 1m memory from node 0. Since node 0 is a top tier node, demotion will be attempted first. This is useful to direct proactive reclaim to specific nodes that are under pressure. $ echo "1m nodes=2,3" > memory.reclaim This instructs the kernel to attempt to reclaim 1m memory in the second tier, since this tier of memory has no demotion targets the memory will be reclaimed. $ echo "1m nodes=0,1" > memory.reclaim Instructs the kernel to reclaim memory from the top tier nodes, which can be desirable according to the userspace policy if there is pressure on the top tiers. Since these nodes have demotion targets, the kernel will attempt demotion first. Since commit 3f1509c57b1b ("Revert "mm/vmscan: never demote for memcg reclaim""), the proactive reclaim interface memory.reclaim does both reclaim and demotion. Reclaim and demotion incur different latency costs to the jobs in the cgroup. Demoted memory would still be addressable by the userspace at a higher latency, but reclaimed memory would need to incur a pagefault. The 'nodes' arg is useful to allow the userspace to control demotion and reclaim independently according to its policy: if the memory.reclaim is called on a node with demotion targets, it will attempt demotion first; if it is called on a node without demotion targets, it will only attempt reclaim. Link: https://lkml.kernel.org/r/20221202223533.1785418-1-almasrymina@google.com Signed-off-by: Mina Almasry Acked-by: Michal Hocko Acked-by: Shakeel Butt Acked-by: Muchun Song Cc: Bagas Sanjaya Cc: "Huang, Ying" Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Roman Gushchin Cc: Tejun Heo Cc: Wei Xu Cc: Yang Shi Cc: Yosry Ahmed Cc: zefan li Signed-off-by: Andrew Morton --- mm/memcontrol.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 54 insertions(+), 13 deletions(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2c7a91689fef..ff65bc23be13 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -63,6 +63,7 @@ #include #include #include +#include #include "internal.h" #include #include @@ -2392,7 +2393,8 @@ static unsigned long reclaim_high(struct mem_cgroup *memcg, psi_memstall_enter(&pflags); nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, - MEMCG_RECLAIM_MAY_SWAP); + MEMCG_RECLAIM_MAY_SWAP, + NULL); psi_memstall_leave(&pflags); } while ((memcg = parent_mem_cgroup(memcg)) && !mem_cgroup_is_root(memcg)); @@ -2683,7 +2685,8 @@ retry: psi_memstall_enter(&pflags); nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages, - gfp_mask, reclaim_options); + gfp_mask, reclaim_options, + NULL); psi_memstall_leave(&pflags); if (mem_cgroup_margin(mem_over_limit) >= nr_pages) @@ -3503,7 +3506,8 @@ static int mem_cgroup_resize_max(struct mem_cgroup *memcg, } if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, - memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP)) { + memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP, + NULL)) { ret = -EBUSY; break; } @@ -3614,7 +3618,8 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) return -EINTR; if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, - MEMCG_RECLAIM_MAY_SWAP)) + MEMCG_RECLAIM_MAY_SWAP, + NULL)) nr_retries--; } @@ -6418,7 +6423,8 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, } reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high, - GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP); + GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP, + NULL); if (!reclaimed && !nr_retries--) break; @@ -6467,7 +6473,8 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, if (nr_reclaims) { if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max, - GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP)) + GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP, + NULL)) nr_reclaims--; continue; } @@ -6590,21 +6597,54 @@ static ssize_t memory_oom_group_write(struct kernfs_open_file *of, return nbytes; } +enum { + MEMORY_RECLAIM_NODES = 0, + MEMORY_RECLAIM_NULL, +}; + +static const match_table_t if_tokens = { + { MEMORY_RECLAIM_NODES, "nodes=%s" }, + { MEMORY_RECLAIM_NULL, NULL }, +}; + static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); unsigned int nr_retries = MAX_RECLAIM_RETRIES; unsigned long nr_to_reclaim, nr_reclaimed = 0; - unsigned int reclaim_options; - int err; + unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP | + MEMCG_RECLAIM_PROACTIVE; + char *old_buf, *start; + substring_t args[MAX_OPT_ARGS]; + int token; + char value[256]; + nodemask_t nodemask = NODE_MASK_ALL; buf = strstrip(buf); - err = page_counter_memparse(buf, "", &nr_to_reclaim); - if (err) - return err; - reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE; + old_buf = buf; + nr_to_reclaim = memparse(buf, &buf) / PAGE_SIZE; + if (buf == old_buf) + return -EINVAL; + + buf = strstrip(buf); + + while ((start = strsep(&buf, " ")) != NULL) { + if (!strlen(start)) + continue; + token = match_token(start, if_tokens, args); + match_strlcpy(value, args, sizeof(value)); + switch (token) { + case MEMORY_RECLAIM_NODES: + if (nodelist_parse(value, nodemask) < 0) + return -EINVAL; + break; + default: + return -EINVAL; + } + } + while (nr_reclaimed < nr_to_reclaim) { unsigned long reclaimed; @@ -6621,7 +6661,8 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf, reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_to_reclaim - nr_reclaimed, - GFP_KERNEL, reclaim_options); + GFP_KERNEL, reclaim_options, + &nodemask); if (!reclaimed && !nr_retries--) return -EAGAIN; -- cgit v1.2.3-70-g09d2