On Wed, Nov 8, 2023 at 11:46 AM Chris Li <chrisl@xxxxxxxxxx> wrote: > > Hi Nhat, > > Sorry for being late to the party. I want to take a look at your patches series. > However I wasn't able to "git am" your patches series cleanly on current > mm-stable, mm-unstable or linux tip. > > $ git am patches/v5_20231106_nphamcs_workload_specific_and_memory_pressure_driven_zswap_writeback.mbx > Applying: list_lru: allows explicit memcg and NUMA node selection > Applying: memcontrol: allows mem_cgroup_iter() to check for onlineness > Applying: zswap: make shrinking memcg-aware (fix) > error: patch failed: mm/zswap.c:174 > error: mm/zswap.c: patch does not apply > Patch failed at 0003 zswap: make shrinking memcg-aware (fix) Ah that was meant to be a fixlet - so that on top of the original "zswap: make shrinking memcg-aware" patch. The intention was to eventually squash it... But this is getting a bit annoyingly confusing, I admit. I just rebased to mm-unstable + squashed it all again, then sent one single replacement patch: [PATCH v5 3/6 REPLACE] zswap: make shrinking memcg-aware Let me know if this still fails to apply. If not, I'll send the whole thing again as v6! My sincerest apologies for the troubles and confusion :( > > What is the base of your patches? A git hash or a branch I can pull > from would be > nice. > > Thanks > > Chris > > On Mon, Nov 6, 2023 at 10:32 AM Nhat Pham <nphamcs@xxxxxxxxx> wrote: > > > > Changelog: > > v5: > > * Replace reference getting with an rcu_read_lock() section for > > zswap lru modifications (suggested by Yosry) > > * Add a new prep patch that allows mem_cgroup_iter() to return > > online cgroup. > > * Add a callback that updates pool->next_shrink when the cgroup is > > offlined (suggested by Yosry Ahmed, Johannes Weiner) > > v4: > > * Rename list_lru_add to list_lru_add_obj and __list_lru_add to > > list_lru_add (patch 1) (suggested by Johannes Weiner and > > Yosry Ahmed) > > * Some cleanups on the memcg aware LRU patch (patch 2) > > (suggested by Yosry Ahmed) > > * Use event interface for the new per-cgroup writeback counters. > > (patch 3) (suggested by Yosry Ahmed) > > * Abstract zswap's lruvec states and handling into > > zswap_lruvec_state (patch 5) (suggested by Yosry Ahmed) > > v3: > > * Add a patch to export per-cgroup zswap writeback counters > > * Add a patch to update zswap's kselftest > > * Separate the new list_lru functions into its own prep patch > > * Do not start from the top of the hierarchy when encounter a memcg > > that is not online for the global limit zswap writeback (patch 2) > > (suggested by Yosry Ahmed) > > * Do not remove the swap entry from list_lru in > > __read_swapcache_async() (patch 2) (suggested by Yosry Ahmed) > > * Removed a redundant zswap pool getting (patch 2) > > (reported by Ryan Roberts) > > * Use atomic for the nr_zswap_protected (instead of lruvec's lock) > > (patch 5) (suggested by Yosry Ahmed) > > * Remove the per-cgroup zswap shrinker knob (patch 5) > > (suggested by Yosry Ahmed) > > v2: > > * Fix loongarch compiler errors > > * Use pool stats instead of memcg stats when !CONFIG_MEMCG_KEM > > > > There are currently several issues with zswap writeback: > > > > 1. There is only a single global LRU for zswap, making it impossible to > > perform worload-specific shrinking - an memcg under memory pressure > > cannot determine which pages in the pool it owns, and often ends up > > writing pages from other memcgs. This issue has been previously > > observed in practice and mitigated by simply disabling > > memcg-initiated shrinking: > > > > https://lore.kernel.org/all/20230530232435.3097106-1-nphamcs@xxxxxxxxx/T/#u > > > > But this solution leaves a lot to be desired, as we still do not > > have an avenue for an memcg to free up its own memory locked up in > > the zswap pool. > > > > 2. We only shrink the zswap pool when the user-defined limit is hit. > > This means that if we set the limit too high, cold data that are > > unlikely to be used again will reside in the pool, wasting precious > > memory. It is hard to predict how much zswap space will be needed > > ahead of time, as this depends on the workload (specifically, on > > factors such as memory access patterns and compressibility of the > > memory pages). > > > > This patch series solves these issues by separating the global zswap > > LRU into per-memcg and per-NUMA LRUs, and performs workload-specific > > (i.e memcg- and NUMA-aware) zswap writeback under memory pressure. The > > new shrinker does not have any parameter that must be tuned by the > > user, and can be opted in or out on a per-memcg basis. > > > > As a proof of concept, we ran the following synthetic benchmark: > > build the linux kernel in a memory-limited cgroup, and allocate some > > cold data in tmpfs to see if the shrinker could write them out and > > improved the overall performance. Depending on the amount of cold data > > generated, we observe from 14% to 35% reduction in kernel CPU time used > > in the kernel builds. > > > > Domenico Cerasuolo (3): > > zswap: make shrinking memcg-aware > > mm: memcg: add per-memcg zswap writeback stat > > selftests: cgroup: update per-memcg zswap writeback selftest > > > > Nhat Pham (3): > > list_lru: allows explicit memcg and NUMA node selection > > memcontrol: allows mem_cgroup_iter() to check for onlineness > > zswap: shrinks zswap pool based on memory pressure > > > > Documentation/admin-guide/mm/zswap.rst | 7 + > > drivers/android/binder_alloc.c | 5 +- > > fs/dcache.c | 8 +- > > fs/gfs2/quota.c | 6 +- > > fs/inode.c | 4 +- > > fs/nfs/nfs42xattr.c | 8 +- > > fs/nfsd/filecache.c | 4 +- > > fs/xfs/xfs_buf.c | 6 +- > > fs/xfs/xfs_dquot.c | 2 +- > > fs/xfs/xfs_qm.c | 2 +- > > include/linux/list_lru.h | 46 ++- > > include/linux/memcontrol.h | 9 +- > > include/linux/mmzone.h | 2 + > > include/linux/vm_event_item.h | 1 + > > include/linux/zswap.h | 27 +- > > mm/list_lru.c | 48 ++- > > mm/memcontrol.c | 20 +- > > mm/mmzone.c | 1 + > > mm/shrinker.c | 4 +- > > mm/swap.h | 3 +- > > mm/swap_state.c | 26 +- > > mm/vmscan.c | 26 +- > > mm/vmstat.c | 1 + > > mm/workingset.c | 4 +- > > mm/zswap.c | 430 +++++++++++++++++--- > > tools/testing/selftests/cgroup/test_zswap.c | 74 ++-- > > 26 files changed, 625 insertions(+), 149 deletions(-) > > > > -- > > 2.34.1 > >
