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Sridhar" Cc: hannes@cmpxchg.org, nphamcs@gmail.com, chengming.zhou@linux.dev, akpm@linux-foundation.org, linux-mm@kvack.org, herbert@gondor.apana.org.au, davem@davemloft.net, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, rientjes@google.com, willy@infradead.org, senozhatsky@chromium.org Subject: Re: [PATCH v1 7/8] mm: zswap: Optimally place members of struct zswap_pool, struct zswap_entry. Message-ID: References: <20261008182814.27450-1-kanchanapsridhar2026@gmail.com> <20261008182814.27450-8-kanchanapsridhar2026@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261008182814.27450-8-kanchanapsridhar2026@gmail.com> X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 738944000A X-Stat-Signature: jzabiqpatsxgjmb8wni4bnbi5ebqus87 X-HE-Tag: 1791992580-789814 X-HE-Meta: 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 apwbHCII gGwTAXccz2SheaZMsMJUt5aCPHCLTrnfd4shE4YpmZrpV3HJtgD8W6MPdctWHeiqmLYLPqw6srBlHyC1VdVUTFdRH8e9HXVUfNJjnbw0wWBo9WI0h3hHu0urN45FV0tabm4XsDykbXfVHtSgONekj7grfx87K42Kb1ck3WsTKcnQK6MfIzP1aAUG13Nx3PUinvd+ZBlBcAm+yX5JryyBXeGbyLWqG82a0XeLrJomEWufhJLpH6crSSU8NF24JdhkiXtmfIeX+Nx3B3xUPx5TYLW3Zl924wUOCywYww/Vgp+g8j+ZX5cSMiHh3KrPRZLT51ktkktHeAe5HNCK99nIVkc3yroq8udK5GV+LV1PF78IIxXY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Oct 08, 2026 at 11:28:13AM -0700, Kanchana P. Sridhar wrote: > Place and align the members of struct zswap_pool and struct zswap_entry > such that members used together in compress/decompress hot paths are > able to share the same cacheline. Minimize holes within these structs > while doing so. > > Signed-off-by: Kanchana P. Sridhar > --- > mm/zswap.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/mm/zswap.c b/mm/zswap.c > index 8ae67fd10522..ade84ac4076e 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -160,11 +160,11 @@ struct crypto_acomp_ctx { > struct zswap_pool { > struct zs_pool *zs_pool; > struct crypto_acomp_ctx __percpu *acomp_ctx; > - u8 compr_batch_size; > struct percpu_ref ref; > - struct rcu_work release_rwork; > - struct hlist_node node; > u8 idx; > + u8 compr_batch_size; > + struct hlist_node node; > + struct rcu_work release_rwork; compr_batch_size is added by this series, why not just add it before idx to begin with? > char tfm_name[CRYPTO_MAX_ALG_NAME]; > }; > > @@ -202,10 +202,10 @@ static struct shrinker *zswap_shrinker; > * logic if referenced is unset. See comments in the shrinker > * section for context. > * nid - NUMA node id of the page for which this is the zswap entry. > - * pool_idx - id of the zswap_pool that the entry's data is in. > * handle - zsmalloc allocation handle that stores the compressed page data > * objcg - the obj_cgroup that the compressed memory is charged to > * lru - handle to the pool's lru used to evict pages. > + * pool_idx - id of the zswap_pool that the entry's data is in. > */ > struct zswap_entry { > swp_entry_t swpentry; > @@ -214,10 +214,10 @@ struct zswap_entry { > bool referenced:1; > }; > int nid; > - u8 pool_idx; > unsigned long handle; > struct obj_cgroup *objcg; > struct list_head lru; > + u8 pool_idx; As mentioned previously, this needs to be packed with the length. > }; > > /* > -- > 2.39.5 >