linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Vlastimil Babka <vbabka@suse.cz>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Christoph Lameter <cl@linux.com>,
	David Rientjes <rientjes@google.com>,
	Pekka Enberg <penberg@kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mel Gorman <mgorman@techsingularity.net>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Jann Horn <jannh@google.com>, Vlastimil Babka <vbabka@suse.cz>
Subject: [RFC 18/26] mm, slub: call deactivate_slab() without disabling irqs
Date: Tue, 25 May 2021 01:39:38 +0200	[thread overview]
Message-ID: <20210524233946.20352-19-vbabka@suse.cz> (raw)
In-Reply-To: <20210524233946.20352-1-vbabka@suse.cz>

The function is now safe to be called with irqs enabled, so move the calls
outside of irq disabled sections.

When called from ___slab_alloc() -> flush_slab() we have irqs disabled, so to
reenable them before deactivate_slab() we need to open-code flush_slab() in
___slab_alloc() and reenable irqs after modifying the kmem_cache_cpu fields.
But that means another irq might have assigned a new c->page so we have to
retry the whole check.

The remaining callers of flush_slab() are the IPI handler which has disabled
irqs anyway, and slub_cpu_dead() which will be dealt with in the following
patch.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 0f58859165bf..01422c757f9b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2722,8 +2722,8 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	freelist = c->freelist;
 	c->page = NULL;
 	c->freelist = NULL;
-	deactivate_slab(s, page, freelist);
 	local_irq_restore(flags);
+	deactivate_slab(s, page, freelist);
 
 new_slab:
 
@@ -2792,18 +2792,31 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		 */
 		goto return_single;
 
+retry_load_page:
 	local_irq_save(flags);
-	if (unlikely(c->page))
-		flush_slab(s, c);
+	if (unlikely(c->page)) {
+		void *flush_freelist = c->freelist;
+		struct page *flush_page = c->page;
+
+		c->page = NULL;
+		c->freelist = NULL;
+		c->tid = next_tid(c->tid);
+
+		local_irq_restore(flags);
+
+		deactivate_slab(s, flush_page, flush_freelist);
+
+		stat(s, CPUSLAB_FLUSH);
+
+		goto retry_load_page;
+	}
 	c->page = page;
 
 	goto load_freelist;
 
 return_single:
 
-	local_irq_save(flags);
 	deactivate_slab(s, page, get_freepointer(s, freelist));
-	local_irq_restore(flags);
 	return freelist;
 }
 
-- 
2.31.1


  parent reply	other threads:[~2021-05-24 23:42 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-24 23:39 [RFC 00/26] SLUB: use local_lock for kmem_cache_cpu protection and reduce " Vlastimil Babka
2021-05-24 23:39 ` [RFC 01/26] mm, slub: allocate private object map for sysfs listings Vlastimil Babka
2021-05-25  8:06   ` Christoph Lameter
2021-05-25 10:13   ` Mel Gorman
2021-05-24 23:39 ` [RFC 02/26] mm, slub: allocate private object map for validate_slab_cache() Vlastimil Babka
2021-05-25  8:09   ` Christoph Lameter
2021-05-25 10:17   ` Mel Gorman
2021-05-25 10:36     ` Vlastimil Babka
2021-05-25 11:33       ` Mel Gorman
2021-06-08 10:37         ` Vlastimil Babka
2021-05-24 23:39 ` [RFC 03/26] mm, slub: don't disable irq for debug_check_no_locks_freed() Vlastimil Babka
2021-05-25 10:24   ` Mel Gorman
2021-05-24 23:39 ` [RFC 04/26] mm, slub: simplify kmem_cache_cpu and tid setup Vlastimil Babka
2021-05-25 11:47   ` Mel Gorman
2021-05-24 23:39 ` [RFC 05/26] mm, slub: extract get_partial() from new_slab_objects() Vlastimil Babka
2021-05-25  9:03   ` Christoph Lameter
2021-05-25 11:54   ` Mel Gorman
2021-05-24 23:39 ` [RFC 06/26] mm, slub: dissolve new_slab_objects() into ___slab_alloc() Vlastimil Babka
2021-05-25  9:06   ` Christoph Lameter
2021-05-25 11:59   ` Mel Gorman
2021-05-24 23:39 ` [RFC 07/26] mm, slub: return slab page from get_partial() and set c->page afterwards Vlastimil Babka
2021-05-25  9:12   ` Christoph Lameter
2021-06-08 10:48     ` Vlastimil Babka
2021-05-24 23:39 ` [RFC 08/26] mm, slub: restructure new page checks in ___slab_alloc() Vlastimil Babka
2021-05-25 12:09   ` Mel Gorman
2021-05-24 23:39 ` [RFC 09/26] mm, slub: move disabling/enabling irqs to ___slab_alloc() Vlastimil Babka
2021-05-25 12:35   ` Mel Gorman
2021-05-25 12:47     ` Vlastimil Babka
2021-05-25 15:10       ` Mel Gorman
2021-05-25 17:24       ` Vlastimil Babka
2021-05-24 23:39 ` [RFC 10/26] mm, slub: do initial checks in ___slab_alloc() with irqs enabled Vlastimil Babka
2021-05-25 13:04   ` Mel Gorman
2021-06-08 12:13     ` Vlastimil Babka
2021-05-24 23:39 ` [RFC 11/26] mm, slub: move disabling irqs closer to get_partial() in ___slab_alloc() Vlastimil Babka
2021-05-25 16:00   ` Jann Horn
2021-05-24 23:39 ` [RFC 12/26] mm, slub: restore irqs around calling new_slab() Vlastimil Babka
2021-05-24 23:39 ` [RFC 13/26] mm, slub: validate partial and newly allocated slabs before loading them Vlastimil Babka
2021-05-24 23:39 ` [RFC 14/26] mm, slub: check new pages with restored irqs Vlastimil Babka
2021-05-24 23:39 ` [RFC 15/26] mm, slub: stop disabling irqs around get_partial() Vlastimil Babka
2021-05-24 23:39 ` [RFC 16/26] mm, slub: move reset of c->page and freelist out of deactivate_slab() Vlastimil Babka
2021-05-24 23:39 ` [RFC 17/26] mm, slub: make locking in deactivate_slab() irq-safe Vlastimil Babka
2021-05-24 23:39 ` Vlastimil Babka [this message]
2021-05-24 23:39 ` [RFC 19/26] mm, slub: move irq control into unfreeze_partials() Vlastimil Babka
2021-05-24 23:39 ` [RFC 20/26] mm, slub: discard slabs in unfreeze_partials() without irqs disabled Vlastimil Babka
2021-05-24 23:39 ` [RFC 21/26] mm, slub: detach whole partial list at once in unfreeze_partials() Vlastimil Babka
2021-05-24 23:39 ` [RFC 22/26] mm, slub: detach percpu partial list in unfreeze_partials() using this_cpu_cmpxchg() Vlastimil Babka
2021-05-24 23:39 ` [RFC 23/26] mm, slub: only disable irq with spin_lock in __unfreeze_partials() Vlastimil Babka
2021-05-24 23:39 ` [RFC 24/26] mm, slub: don't disable irqs in slub_cpu_dead() Vlastimil Babka
2021-05-24 23:39 ` [RFC 25/26] mm, slub: use migrate_disable() in put_cpu_partial() Vlastimil Babka
2021-05-25 15:33   ` Jann Horn
2021-06-09  8:41     ` Vlastimil Babka
2021-05-24 23:39 ` [RFC 26/26] mm, slub: convert kmem_cpu_slab protection to local_lock Vlastimil Babka
2021-05-25 16:11   ` Vlastimil Babka

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=20210524233946.20352-19-vbabka@suse.cz \
    --to=vbabka@suse.cz \
    --cc=bigeasy@linutronix.de \
    --cc=brouer@redhat.com \
    --cc=cl@linux.com \
    --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=peterz@infradead.org \
    --cc=rientjes@google.com \
    --cc=tglx@linutronix.de \
    --subject='Re: [RFC 18/26] mm, slub: call deactivate_slab() without disabling irqs' \
    /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

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).