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https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
synced 2025-09-29 12:19:07 +10:00
f1221c8442
The damon_sample_wsse_start() can fail so we must reset the "enable"
parameter to "false" again for proper rollback.
In such cases, setting Y to "enable" then N triggers the similar crash
with wsse because damon sample start failed but the "enable" stays as Y.
Link: https://lkml.kernel.org/r/20250702000205.1921-3-honggyu.kim@sk.com
Fixes: b757c6cfc6 ("samples/damon/wsse: start and stop DAMON as the user requests")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
121 lines
2.4 KiB
C
121 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* working set size estimation: monitor access pattern of given process and
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* print estimated working set size (total size of regions that showing some
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* access).
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*/
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#define pr_fmt(fmt) "damon_sample_wsse: " fmt
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#include <linux/damon.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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static int target_pid __read_mostly;
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module_param(target_pid, int, 0600);
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static int damon_sample_wsse_enable_store(
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const char *val, const struct kernel_param *kp);
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static const struct kernel_param_ops enable_param_ops = {
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.set = damon_sample_wsse_enable_store,
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.get = param_get_bool,
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};
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static bool enable __read_mostly;
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module_param_cb(enable, &enable_param_ops, &enable, 0600);
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MODULE_PARM_DESC(enable, "Enable or disable DAMON_SAMPLE_WSSE");
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static struct damon_ctx *ctx;
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static struct pid *target_pidp;
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static int damon_sample_wsse_after_aggregate(struct damon_ctx *c)
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{
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struct damon_target *t;
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damon_for_each_target(t, c) {
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struct damon_region *r;
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unsigned long wss = 0;
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damon_for_each_region(r, t) {
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if (r->nr_accesses > 0)
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wss += r->ar.end - r->ar.start;
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}
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pr_info("wss: %lu\n", wss);
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}
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return 0;
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}
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static int damon_sample_wsse_start(void)
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{
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struct damon_target *target;
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pr_info("start\n");
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ctx = damon_new_ctx();
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if (!ctx)
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return -ENOMEM;
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if (damon_select_ops(ctx, DAMON_OPS_VADDR)) {
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damon_destroy_ctx(ctx);
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return -EINVAL;
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}
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target = damon_new_target();
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if (!target) {
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damon_destroy_ctx(ctx);
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return -ENOMEM;
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}
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damon_add_target(ctx, target);
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target_pidp = find_get_pid(target_pid);
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if (!target_pidp) {
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damon_destroy_ctx(ctx);
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return -EINVAL;
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}
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target->pid = target_pidp;
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ctx->callback.after_aggregation = damon_sample_wsse_after_aggregate;
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return damon_start(&ctx, 1, true);
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}
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static void damon_sample_wsse_stop(void)
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{
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pr_info("stop\n");
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if (ctx) {
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damon_stop(&ctx, 1);
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damon_destroy_ctx(ctx);
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}
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if (target_pidp)
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put_pid(target_pidp);
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}
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static int damon_sample_wsse_enable_store(
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const char *val, const struct kernel_param *kp)
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{
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bool enabled = enable;
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int err;
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err = kstrtobool(val, &enable);
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if (err)
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return err;
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if (enable == enabled)
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return 0;
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if (enable) {
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err = damon_sample_wsse_start();
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if (err)
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enable = false;
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return err;
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}
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damon_sample_wsse_stop();
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return 0;
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}
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static int __init damon_sample_wsse_init(void)
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{
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return 0;
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}
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module_init(damon_sample_wsse_init);
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