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[23.116.43.216]) by smtp.gmail.com with ESMTPSA id 00721157ae682-7cc991c9b64sm819827b3.1.2026.05.16.15.34.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 May 2026 15:34:52 -0700 (PDT) From: Ravi Jonnalagadda To: sj@kernel.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: akpm@linux-foundation.org, corbet@lwn.net, bijan311@gmail.com, ajayjoshi@micron.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, ravis.opensrc@gmail.com, bharata@amd.com Subject: [RFC PATCH 5/7] mm/damon: add sysfs binding and dispatch hookup for paddr_ibs operations Date: Sat, 16 May 2026 15:34:30 -0700 Message-ID: <20260516223439.4033-6-ravis.opensrc@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260516223439.4033-1-ravis.opensrc@gmail.com> References: <20260516223439.4033-1-ravis.opensrc@gmail.com> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Extend damon_ops_id enum to include DAMON_OPS_PADDR_IBS and add the corresponding 'paddr_ibs' name to the sysfs ops_names array so users can select AMD IBS-based PA-mode monitoring via /sys/kernel/mm/damon/admin/kdamonds//contexts//operations. Route ops that report accesses through the hardware-sampling ring (currently only DAMON_OPS_PADDR_IBS) through the existing kdamond_check_reported_accesses() drain path used for page-fault reports. A small helper damon_ops_is_hw_hotness() centralises the classification so any future paddr-family backend that also reports through the ring just adds a case here. This routing is bound to ops.id rather than to a separate per-context flag. A flag in damon_sample_control would have to be set by the ops .init callback after damon_select_ops() and would then need to be preserved by damon_commit_sample_control() across sysfs commits; deriving from ops.id avoids both pitfalls. Signed-off-by: Ravi Jonnalagadda --- include/linux/damon.h | 2 ++ mm/damon/core.c | 13 ++++++++++++- mm/damon/sysfs.c | 12 +++++++++--- 3 files changed, 23 insertions(+), 4 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 35cc3d42fcba8..16da528845d03 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -669,12 +669,14 @@ struct damos { * @DAMON_OPS_FVADDR: Monitoring operations for only fixed ranges of virtual * address spaces * @DAMON_OPS_PADDR: Monitoring operations for the physical address space + * @DAMON_OPS_PADDR_IBS: AMD IBS-based PA-mode monitoring * @NR_DAMON_OPS: Number of monitoring operations implementations */ enum damon_ops_id { DAMON_OPS_VADDR, DAMON_OPS_FVADDR, DAMON_OPS_PADDR, + DAMON_OPS_PADDR_IBS, NR_DAMON_OPS, }; diff --git a/mm/damon/core.c b/mm/damon/core.c index 03f9c671e8bc9..2aa031cbc70b7 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -73,6 +73,16 @@ static bool __damon_is_registered_ops(enum damon_ops_id id) return true; } +/* + * Returns true if the given ops id reports access samples through the + * hardware-sampling ring-buffer drain path (rather than its own + * .check_accesses callback). + */ +static bool damon_ops_is_hw_hotness(enum damon_ops_id id) +{ + return id == DAMON_OPS_PADDR_IBS; +} + /** * damon_is_registered_ops() - Check if a given damon_operations is registered. * @id: Id of the damon_operations to check if registered. @@ -4048,7 +4058,8 @@ static int kdamond_fn(void *data) ctx->passed_sample_intervals++; /* todo: make these non-exclusive */ - if (ctx->sample_control.primitives_enabled.page_fault) + if (ctx->sample_control.primitives_enabled.page_fault || + damon_ops_is_hw_hotness(ctx->ops.id)) max_nr_accesses = kdamond_check_reported_accesses(ctx); else if (ctx->ops.check_accesses) max_nr_accesses = ctx->ops.check_accesses(ctx); diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c index fc7256e522a69..261ccf0c61846 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1388,6 +1388,10 @@ static const struct damon_sysfs_ops_name damon_sysfs_ops_names[] = { .ops_id = DAMON_OPS_PADDR, .name = "paddr", }, + { + .ops_id = DAMON_OPS_PADDR_IBS, + .name = "paddr_ibs", + }, }; struct damon_sysfs_context { @@ -2023,7 +2027,8 @@ static int damon_sysfs_add_targets(struct damon_ctx *ctx, int i, err; /* Multiple physical address space monitoring targets makes no sense */ - if (ctx->ops.id == DAMON_OPS_PADDR && sysfs_targets->nr > 1) + if ((ctx->ops.id == DAMON_OPS_PADDR || + ctx->ops.id == DAMON_OPS_PADDR_IBS) && sysfs_targets->nr > 1) return -EINVAL; for (i = 0; i < sysfs_targets->nr; i++) { @@ -2072,8 +2077,9 @@ static int damon_sysfs_apply_inputs(struct damon_ctx *ctx, if (err) return err; ctx->addr_unit = sys_ctx->addr_unit; - /* addr_unit is respected by only DAMON_OPS_PADDR */ - if (sys_ctx->ops_id == DAMON_OPS_PADDR) + /* addr_unit is respected by only paddr-family ops */ + if (sys_ctx->ops_id == DAMON_OPS_PADDR || + sys_ctx->ops_id == DAMON_OPS_PADDR_IBS) ctx->min_region_sz = max( DAMON_MIN_REGION_SZ / sys_ctx->addr_unit, 1); ctx->pause = sys_ctx->pause; -- 2.43.0