From patchwork Mon Nov 18 21:20:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13879090 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AA6C188CDC; Mon, 18 Nov 2024 21:20:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731964845; cv=none; b=YJeZM+NjpmKDFHrJiS1qitQeHZ1jQSJLU+WNmXFXERxz4HEKQz3uKaWrMcD6DHAhRLNq0nH9FBXGVL9lz+CS4DknHqV8RLJrTixxN7fNQd4JGJHGDsGRiFgrPKuWTDR885nKivqANh47oIrVbL98+2c4DTFY+o4u97q+Kj5SSj8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731964845; c=relaxed/simple; bh=YSMul3zw+HmB+qz3x/7fZ6XJUuiVCmfFxqBH5tPUNoM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DUN+jOP8gwmq4bhFeE8ihWnoUSnERrpxB5v32xHazc+aTvisVKx5/uyfHGFGnUh8CyqYzraB/ftWZ9R7oX1dyRXvxsRgZzRwJHW8Xcan6cHehEQpgcrTZgdrxPhxIYGZEvqzT0ujUBa62jU4qe5I/NDlZtp+D0Ks3NRQZU9kVEE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JojPLaEe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JojPLaEe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F13CAC4CECF; Mon, 18 Nov 2024 21:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731964845; bh=YSMul3zw+HmB+qz3x/7fZ6XJUuiVCmfFxqBH5tPUNoM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JojPLaEere5icSbYJqDCL1qv2ci2rMFxdhtdhCSAWdCbMwDZanK29K7Np+GIqFqQg IIikghJ+o99FQ3O3bu9M0gBPLepELMwmfMrEJLJff+2lmrMNq6SCEFrUC2taGN6coA 4F6osfeMAf18QeMA5SNYD7j30lh0lXTjeGxhZPL7n2PZRufyTC6a0y2qv9C5k1J021 pit7bc2BCwbusPFBOc+tSijPu0xnOQwRbjzHcgrlffb6gqVQvirtyOrc5kqALdKCc5 Q5Al3hYGCtFcpVUYptdGflseP+TgXWIoF8xHC19ZJQCNPoETdE/UluzjbWv08C3LE2 dseioyGxJ6VUg== From: cel@kernel.org To: Cc: , Jeff Layton , Chuck Lever Subject: [PATCH 5.15.y 05/18] NFSD: Replace nfsd_prune_bucket() Date: Mon, 18 Nov 2024 16:20:22 -0500 Message-ID: <20241118212035.3848-11-cel@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241118212035.3848-1-cel@kernel.org> References: <20241118212035.3848-1-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Chuck Lever [ Upstream commit a9507f6af1450ed26a4a36d979af518f5bb21e5d ] Enable nfsd_prune_bucket() to drop the bucket lock while calling kfree(). Use the same pattern that Jeff recently introduced in the NFSD filecache. A few percpu operations are moved outside the lock since they temporarily disable local IRQs which is expensive and does not need to be done while the lock is held. Reviewed-by: Jeff Layton Stable-dep-of: c135e1269f34 ("NFSD: Refactor the duplicate reply cache shrinker") Signed-off-by: Chuck Lever --- fs/nfsd/nfscache.c | 78 +++++++++++++++++++++++++++++++++++++--------- fs/nfsd/trace.h | 22 +++++++++++++ 2 files changed, 85 insertions(+), 15 deletions(-) diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index 938b37dc1679..e60313ce0fb6 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -117,6 +117,21 @@ static void nfsd_cacherep_free(struct svc_cacherep *rp) kmem_cache_free(drc_slab, rp); } +static unsigned long +nfsd_cacherep_dispose(struct list_head *dispose) +{ + struct svc_cacherep *rp; + unsigned long freed = 0; + + while (!list_empty(dispose)) { + rp = list_first_entry(dispose, struct svc_cacherep, c_lru); + list_del(&rp->c_lru); + nfsd_cacherep_free(rp); + freed++; + } + return freed; +} + static void nfsd_cacherep_unlink_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b, struct svc_cacherep *rp) @@ -259,6 +274,41 @@ nfsd_cache_bucket_find(__be32 xid, struct nfsd_net *nn) return &nn->drc_hashtbl[hash]; } +/* + * Remove and return no more than @max expired entries in bucket @b. + * If @max is zero, do not limit the number of removed entries. + */ +static void +nfsd_prune_bucket_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b, + unsigned int max, struct list_head *dispose) +{ + unsigned long expiry = jiffies - RC_EXPIRE; + struct svc_cacherep *rp, *tmp; + unsigned int freed = 0; + + lockdep_assert_held(&b->cache_lock); + + /* The bucket LRU is ordered oldest-first. */ + list_for_each_entry_safe(rp, tmp, &b->lru_head, c_lru) { + /* + * Don't free entries attached to calls that are still + * in-progress, but do keep scanning the list. + */ + if (rp->c_state == RC_INPROG) + continue; + + if (atomic_read(&nn->num_drc_entries) <= nn->max_drc_entries && + time_before(expiry, rp->c_timestamp)) + break; + + nfsd_cacherep_unlink_locked(nn, b, rp); + list_add(&rp->c_lru, dispose); + + if (max && ++freed > max) + break; + } +} + static long prune_bucket(struct nfsd_drc_bucket *b, struct nfsd_net *nn, unsigned int max) { @@ -282,11 +332,6 @@ static long prune_bucket(struct nfsd_drc_bucket *b, struct nfsd_net *nn, return freed; } -static long nfsd_prune_bucket(struct nfsd_drc_bucket *b, struct nfsd_net *nn) -{ - return prune_bucket(b, nn, 3); -} - /* * Walk the LRU list and prune off entries that are older than RC_EXPIRE. * Also prune the oldest ones when the total exceeds the max number of entries. @@ -442,6 +487,8 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp) __wsum csum; struct nfsd_drc_bucket *b; int type = rqstp->rq_cachetype; + unsigned long freed; + LIST_HEAD(dispose); int rtn = RC_DOIT; rqstp->rq_cacherep = NULL; @@ -466,20 +513,18 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp) found = nfsd_cache_insert(b, rp, nn); if (found != rp) goto found_entry; - - nfsd_stats_rc_misses_inc(); rqstp->rq_cacherep = rp; rp->c_state = RC_INPROG; + nfsd_prune_bucket_locked(nn, b, 3, &dispose); + spin_unlock(&b->cache_lock); + freed = nfsd_cacherep_dispose(&dispose); + trace_nfsd_drc_gc(nn, freed); + + nfsd_stats_rc_misses_inc(); atomic_inc(&nn->num_drc_entries); nfsd_stats_drc_mem_usage_add(nn, sizeof(*rp)); - - nfsd_prune_bucket(b, nn); - -out_unlock: - spin_unlock(&b->cache_lock); -out: - return rtn; + goto out; found_entry: /* We found a matching entry which is either in progress or done. */ @@ -517,7 +562,10 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp) out_trace: trace_nfsd_drc_found(nn, rqstp, rtn); - goto out_unlock; +out_unlock: + spin_unlock(&b->cache_lock); +out: + return rtn; } /** diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index 276420ea3b8d..91e9921db725 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -1260,6 +1260,28 @@ TRACE_EVENT(nfsd_drc_mismatch, __entry->ingress) ); +TRACE_EVENT_CONDITION(nfsd_drc_gc, + TP_PROTO( + const struct nfsd_net *nn, + unsigned long freed + ), + TP_ARGS(nn, freed), + TP_CONDITION(freed > 0), + TP_STRUCT__entry( + __field(unsigned long long, boot_time) + __field(unsigned long, freed) + __field(int, total) + ), + TP_fast_assign( + __entry->boot_time = nn->boot_time; + __entry->freed = freed; + __entry->total = atomic_read(&nn->num_drc_entries); + ), + TP_printk("boot_time=%16llx total=%d freed=%lu", + __entry->boot_time, __entry->total, __entry->freed + ) +); + TRACE_EVENT(nfsd_cb_args, TP_PROTO( const struct nfs4_client *clp,