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b=Onb/X5BrLg4E4ya9P6ulS89sPP4Wf3LCW6Wvr0VaxdepBIEJ6oHsCTtcztCm87EjM irMxBSOse6pE15vyf1MZcQYCN6T2Xtvmsy1mng+bHPAd6yi9z+exFbFVufLywVrpR2 aIIaWYfG4Ch/cHncNLxLhynnGtyRVxQ0GiPxtmaL5Vxfb8PFTAUhjk73xln6imMnDR llK+1H9jIIuyRFbnvgEunMo+namHX+txHLpC/1/LVDaxaPtWwCTWSQyyJ8VJYLtsP0 Bz8Jsd9iDFItTMcviDCr4AhVTJOHFTp0cbpzTROESQmYCql3VU6bTZPTrD4pSwXffo Q+JWtYYMZzJ5w== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 01/14] mm/damon: accept parallel damon_call() requests Date: Sun, 6 Jul 2025 13:00:05 -0700 Message-Id: <20250706200018.42704-2-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250706200018.42704-1-sj@kernel.org> References: <20250706200018.42704-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: 585D9A0005 X-Rspamd-Server: rspam09 X-Stat-Signature: 51fjczufsdim1fys7i6xbu7f8p35gs15 X-HE-Tag: 1751832027-52215 X-HE-Meta: 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 xER2L5nW 805mXzPmWIKH88+Oa2bb7XgM25er2ahyXnaOizMKSTgJ05xTKXV3kWuVZarCZLXqRPebSC072Jbcl4YmyINKyc6xBgWlv9+1KWAckUMGlXFb7Le58Fn6Msd2xvvqCRTT/SVVjoxP6vSIATyw82ZsvnP1v8Zfs9FfWCfctvrkHQTBe3lS9Q5AF9fb4tM2zghOh6giXuJxJoD9kvkDLOlM22Eyl8Y0qZSlMdUdAOrxX9+X6Zlk9CIKFcsUzZ1CU7qTMY8bLf1ZtyJjNZpXnSEGx25MO9XDikqsVDJJ8oppin1SBe7CbaMtNhlrZmA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Calling damon_call() while it is serving for another parallel thread immediately fails with -EBUSY. The caller should call it again, later. Each caller implementing such retry logic would be redundant. Accept parallel damon_call() requests and do the wait instead of the caller. Signed-off-by: SeongJae Park --- include/linux/damon.h | 7 +++++-- mm/damon/core.c | 49 ++++++++++++++++++++++--------------------- 2 files changed, 30 insertions(+), 26 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index accd45f203cd..9176a1c7d5a8 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -673,6 +673,8 @@ struct damon_call_control { struct completion completion; /* informs if the kdamond canceled @fn infocation */ bool canceled; + /* List head for siblings. */ + struct list_head list; }; /** @@ -798,8 +800,9 @@ struct damon_ctx { /* for scheme quotas prioritization */ unsigned long *regions_score_histogram; - struct damon_call_control *call_control; - struct mutex call_control_lock; + /* lists of &struct damon_call_control */ + struct list_head call_controls; + struct mutex call_controls_lock; struct damos_walk_control *walk_control; struct mutex walk_control_lock; diff --git a/mm/damon/core.c b/mm/damon/core.c index 45c237ade8cf..01e62bdcdd67 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -533,7 +533,8 @@ struct damon_ctx *damon_new_ctx(void) ctx->next_ops_update_sis = 0; mutex_init(&ctx->kdamond_lock); - mutex_init(&ctx->call_control_lock); + INIT_LIST_HEAD(&ctx->call_controls); + mutex_init(&ctx->call_controls_lock); mutex_init(&ctx->walk_control_lock); ctx->attrs.min_nr_regions = 10; @@ -1353,14 +1354,11 @@ int damon_call(struct damon_ctx *ctx, struct damon_call_control *control) { init_completion(&control->completion); control->canceled = false; + INIT_LIST_HEAD(&control->list); - mutex_lock(&ctx->call_control_lock); - if (ctx->call_control) { - mutex_unlock(&ctx->call_control_lock); - return -EBUSY; - } - ctx->call_control = control; - mutex_unlock(&ctx->call_control_lock); + mutex_lock(&ctx->call_controls_lock); + list_add_tail(&ctx->call_controls, &control->list); + mutex_unlock(&ctx->call_controls_lock); if (!damon_is_running(ctx)) return -EINVAL; wait_for_completion(&control->completion); @@ -2379,11 +2377,11 @@ static void kdamond_usleep(unsigned long usecs) } /* - * kdamond_call() - handle damon_call_control. + * kdamond_call() - handle damon_call_control objects. * @ctx: The &struct damon_ctx of the kdamond. * @cancel: Whether to cancel the invocation of the function. * - * If there is a &struct damon_call_control request that registered via + * If there are &struct damon_call_control requests that registered via * &damon_call() on @ctx, do or cancel the invocation of the function depending * on @cancel. @cancel is set when the kdamond is already out of the main loop * and therefore will be terminated. @@ -2393,21 +2391,24 @@ static void kdamond_call(struct damon_ctx *ctx, bool cancel) struct damon_call_control *control; int ret = 0; - mutex_lock(&ctx->call_control_lock); - control = ctx->call_control; - mutex_unlock(&ctx->call_control_lock); - if (!control) - return; - if (cancel) { - control->canceled = true; - } else { - ret = control->fn(control->data); - control->return_code = ret; + while (true) { + mutex_lock(&ctx->call_controls_lock); + control = list_first_entry_or_null(&ctx->call_controls, + struct damon_call_control, list); + mutex_unlock(&ctx->call_controls_lock); + if (!control) + return; + if (cancel) { + control->canceled = true; + } else { + ret = control->fn(control->data); + control->return_code = ret; + } + mutex_lock(&ctx->call_controls_lock); + list_del(&control->list); + mutex_unlock(&ctx->call_controls_lock); + complete(&control->completion); } - complete(&control->completion); - mutex_lock(&ctx->call_control_lock); - ctx->call_control = NULL; - mutex_unlock(&ctx->call_control_lock); } /* Returns negative error code if it's not activated but should return */ -- 2.39.5