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authorSeongJae Park <sj@kernel.org>2024-04-26 12:52:40 -0700
committerAndrew Morton <akpm@linux-foundation.org>2024-05-05 17:53:54 -0700
commit180d928e55a8160a421aa96b522dc317a6f52140 (patch)
tree65859f56537fe6ee72c8109c795c9340396dcd5c /mm
parent737019cf6ac5babb75645ad324aeead7bc04749d (diff)
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mm/damon/paddr: implement damon_folio_young()
Patch series "mm/damon: add a DAMOS filter type for page granularity access recheck". DAMON provides its best-effort accuracy-overhead tradeoff under the user-defined ranges of acceptable level of the monitoring accuracy and overhead. A recent discussion for tiered memory management support from DAMON[1] concluded that finding memory regions of specific access pattern with low overhead despite of low accuracy via DAMON first, and then double checking the access of the region again in a finer (e.g., page) granularity could be a useful strategy for some DAMOS schemes. Add a new type of DAMOS filter, namely 'young' for such a case. It checks each page of DAMOS target region is accessed since the last check, and filters it out or in if 'matching' parameter is 'true' or 'false', respectively. Because this is a filter type that applied in page granularity, the support depends on DAMON operations set, similar to 'anon' and 'memcg' DAMOS filter types. Implement the support on the DAMON operations set for the physical address space, 'paddr', since one of the expected usages[1] is based on the physical address space. [1] https://lore.kernel.org/r/20240227235121.153277-1-sj@kernel.org This patch (of 7): damon_pa_young() receives physical address, get the folio covering the address, and show if the folio is accessed since the last check. A following commit will reuse the internal logic for checking access to a given folio. To avoid duplication of the code, split the internal logic. Also, change the rmap walker function's name from __damon_pa_young() to damon_folio_young_one(), following the change of the caller's name and the naming rule that more commonly used by other rmap walkers. Link: https://lkml.kernel.org/r/20240426195247.100306-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240426195247.100306-2-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Tested-by: Honggyu Kim <honggyu.kim@sk.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/damon/paddr.c32
1 files changed, 19 insertions, 13 deletions
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 5e6dc312072c..25c3ba2a9eaf 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -79,8 +79,8 @@ static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
}
}
-static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
- unsigned long addr, void *arg)
+static bool damon_folio_young_one(struct folio *folio,
+ struct vm_area_struct *vma, unsigned long addr, void *arg)
{
bool *accessed = arg;
DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
@@ -111,38 +111,44 @@ static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
return *accessed == false;
}
-static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
+static bool damon_folio_young(struct folio *folio)
{
- struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
bool accessed = false;
struct rmap_walk_control rwc = {
.arg = &accessed,
- .rmap_one = __damon_pa_young,
+ .rmap_one = damon_folio_young_one,
.anon_lock = folio_lock_anon_vma_read,
};
bool need_lock;
- if (!folio)
- return false;
-
if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
if (folio_test_idle(folio))
- accessed = false;
+ return false;
else
- accessed = true;
- goto out;
+ return true;
}
need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
if (need_lock && !folio_trylock(folio))
- goto out;
+ return false;
rmap_walk(folio, &rwc);
if (need_lock)
folio_unlock(folio);
-out:
+ return accessed;
+}
+
+static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
+{
+ struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
+ bool accessed;
+
+ if (!folio)
+ return false;
+
+ accessed = damon_folio_young(folio);
*folio_sz = folio_size(folio);
folio_put(folio);
return accessed;