linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Vlastimil Babka <vbabka@suse.cz>
To: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@linux.com>,
	David Rientjes <rientjes@google.com>,
	Pekka Enberg <penberg@kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Mike Galbraith <efault@gmx.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mel Gorman <mgorman@techsingularity.net>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Jann Horn <jannh@google.com>, Vlastimil Babka <vbabka@suse.cz>
Subject: [PATCH v5 32/35] mm, slub: make slab_lock() disable irqs with PREEMPT_RT
Date: Mon, 23 Aug 2021 16:58:23 +0200	[thread overview]
Message-ID: <20210823145826.3857-33-vbabka@suse.cz> (raw)
In-Reply-To: <20210823145826.3857-1-vbabka@suse.cz>

We need to disable irqs around slab_lock() (a bit spinlock) to make it
irq-safe. The calls to slab_lock() are nested under spin_lock_irqsave() which
doesn't disable irqs on PREEMPT_RT, so add explicit disabling with PREEMPT_RT.

We also distinguish cmpxchg_double_slab() where we do the disabling explicitly
and __cmpxchg_double_slab() for contexts with already disabled irqs.  However
these context are also typically spin_lock_irqsave() thus insufficient on
PREEMPT_RT. Thus, change __cmpxchg_double_slab() to be same as
cmpxchg_double_slab() on PREEMPT_RT.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 59722a4bb546..3286defe4857 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -380,12 +380,12 @@ __slab_unlock(struct page *page, unsigned long *flags, bool disable_irqs)
 static __always_inline void
 slab_lock(struct page *page, unsigned long *flags)
 {
-	__slab_lock(page, flags, false);
+	__slab_lock(page, flags, IS_ENABLED(CONFIG_PREEMPT_RT));
 }
 
 static __always_inline void slab_unlock(struct page *page, unsigned long *flags)
 {
-	__slab_unlock(page, flags, false);
+	__slab_unlock(page, flags, IS_ENABLED(CONFIG_PREEMPT_RT));
 }
 
 static inline bool ___cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
@@ -429,14 +429,19 @@ static inline bool ___cmpxchg_double_slab(struct kmem_cache *s, struct page *pag
 	return false;
 }
 
-/* Interrupts must be disabled (for the fallback code to work right) */
+/*
+ * Interrupts must be disabled (for the fallback code to work right), typically
+ * by an _irqsave() lock variant. Except on PREEMPT_RT where locks are different
+ * so we disable interrupts explicitly here.
+ */
 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 		void *freelist_old, unsigned long counters_old,
 		void *freelist_new, unsigned long counters_new,
 		const char *n)
 {
 	return ___cmpxchg_double_slab(s, page, freelist_old, counters_old,
-				      freelist_new, counters_new, n, false);
+				      freelist_new, counters_new, n,
+				      IS_ENABLED(CONFIG_PREEMPT_RT));
 }
 
 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
-- 
2.32.0


  parent reply	other threads:[~2021-08-23 15:01 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-23 14:57 [PATCH v5 00/35] SLUB: reduce irq disabled scope and make it RT compatible Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 01/35] mm, slub: don't call flush_all() from slab_debug_trace_open() Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 02/35] mm, slub: allocate private object map for debugfs listings Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 03/35] mm, slub: allocate private object map for validate_slab_cache() Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 04/35] mm, slub: don't disable irq for debug_check_no_locks_freed() Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 05/35] mm, slub: remove redundant unfreeze_partials() from put_cpu_partial() Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 06/35] mm, slub: unify cmpxchg_double_slab() and __cmpxchg_double_slab() Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 07/35] mm, slub: extract get_partial() from new_slab_objects() Vlastimil Babka
2021-08-23 14:57 ` [PATCH v5 08/35] mm, slub: dissolve new_slab_objects() into ___slab_alloc() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 09/35] mm, slub: return slab page from get_partial() and set c->page afterwards Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 10/35] mm, slub: restructure new page checks in ___slab_alloc() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 11/35] mm, slub: simplify kmem_cache_cpu and tid setup Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 12/35] mm, slub: move disabling/enabling irqs to ___slab_alloc() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 13/35] mm, slub: do initial checks in ___slab_alloc() with irqs enabled Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 14/35] mm, slub: move disabling irqs closer to get_partial() in ___slab_alloc() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 15/35] mm, slub: restore irqs around calling new_slab() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 16/35] mm, slub: validate slab from partial list or page allocator before making it cpu slab Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 17/35] mm, slub: check new pages with restored irqs Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 18/35] mm, slub: stop disabling irqs around get_partial() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 19/35] mm, slub: move reset of c->page and freelist out of deactivate_slab() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 20/35] mm, slub: make locking in deactivate_slab() irq-safe Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 21/35] mm, slub: call deactivate_slab() without disabling irqs Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 22/35] mm, slub: move irq control into unfreeze_partials() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 23/35] mm, slub: discard slabs in unfreeze_partials() without irqs disabled Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 24/35] mm, slub: detach whole partial list at once in unfreeze_partials() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 25/35] mm, slub: separate detaching of partial list in unfreeze_partials() from unfreezing Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 26/35] mm, slub: only disable irq with spin_lock in __unfreeze_partials() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 27/35] mm, slub: don't disable irqs in slub_cpu_dead() Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 28/35] mm, slab: make flush_slab() possible to call with irqs enabled Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 29/35] mm: slub: Move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 30/35] mm: slub: Make object_map_lock a raw_spinlock_t Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 31/35] mm, slub: optionally save/restore irqs in slab_[un]lock()/ Vlastimil Babka
2021-08-23 14:58 ` Vlastimil Babka [this message]
2021-08-23 14:58 ` [PATCH v5 33/35] mm, slub: protect put_cpu_partial() with disabled irqs instead of cmpxchg Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 34/35] mm, slub: use migrate_disable() on PREEMPT_RT Vlastimil Babka
2021-08-23 14:58 ` [PATCH v5 35/35] mm, slub: convert kmem_cpu_slab protection to local_lock Vlastimil Babka
2021-08-23 15:11 ` [PATCH v5 00/35] SLUB: reduce irq disabled scope and make it RT compatible Sebastian Andrzej Siewior

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210823145826.3857-33-vbabka@suse.cz \
    --to=vbabka@suse.cz \
    --cc=akpm@linux-foundation.org \
    --cc=bigeasy@linutronix.de \
    --cc=brouer@redhat.com \
    --cc=cl@linux.com \
    --cc=efault@gmx.de \
    --cc=iamjoonsoo.kim@lge.com \
    --cc=jannh@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mgorman@techsingularity.net \
    --cc=penberg@kernel.org \
    --cc=rientjes@google.com \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).