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From: Julien Grall <julien.grall@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com,
	linux-kernel@vger.kernel.org,
	Julien Grall <julien.grall@citrix.com>,
	Stefano Stabellini <stefano.stabellini@citrix.com>,
	David Vrabel <david.vrabel@citrix.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 13/20] xen/events: fifo: Make it running on 64KB granularity
Date: Mon, 7 Sep 2015 16:33:51 +0100	[thread overview]
Message-ID: <1441640038-23615-14-git-send-email-julien.grall__46376.0806866505$1441640408$gmane$org@citrix.com> (raw)
In-Reply-To: <1441640038-23615-1-git-send-email-julien.grall@citrix.com>

Only use the first 4KB of the page to store the events channel info. It
means that we will waste 60KB every time we allocate page for:
     * control block: a page is allocating per CPU
     * event array: a page is allocating everytime we need to expand it

I think we can reduce the memory waste for the 2 areas by:

    * control block: sharing between multiple vCPUs. Although it will
    require some bookkeeping in order to not free the page when the CPU
    goes offline and the other CPUs sharing the page still there

    * event array: always extend the array event by 64K (i.e 16 4K
    chunk). That would require more care when we fail to expand the
    event channel.

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@citrix.com>

---
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>

    Note I haven't updated the suggestion to reduce the memory waste
    after David's email [1]. I can do it if necessary.

    Changes in v3:
        - Add David and Stefano's reviewed-by

    [1] http://lists.xen.org/archives/html/xen-devel/2015-07/msg04596.html
---
 drivers/xen/events/events_base.c | 2 +-
 drivers/xen/events/events_fifo.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index c49bb7a..00dd923 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -40,11 +40,11 @@
 #include <asm/idle.h>
 #include <asm/io_apic.h>
 #include <asm/xen/pci.h>
-#include <xen/page.h>
 #endif
 #include <asm/sync_bitops.h>
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
+#include <xen/page.h>
 
 #include <xen/xen.h>
 #include <xen/hvm.h>
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 1d4baf5..e3e9e3d 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -54,7 +54,7 @@
 
 #include "events_internal.h"
 
-#define EVENT_WORDS_PER_PAGE (PAGE_SIZE / sizeof(event_word_t))
+#define EVENT_WORDS_PER_PAGE (XEN_PAGE_SIZE / sizeof(event_word_t))
 #define MAX_EVENT_ARRAY_PAGES (EVTCHN_FIFO_NR_CHANNELS / EVENT_WORDS_PER_PAGE)
 
 struct evtchn_fifo_queue {
-- 
2.1.4

  parent reply	other threads:[~2015-09-07 15:38 UTC|newest]

Thread overview: 143+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-07 15:33 [PATCH v4 00/20] xen/arm64: Add support for 64KB page in Linux Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 01/20] net/xen-netback: xenvif_gop_frag_copy: move GSO check out of the loop Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 02/20] arm/xen: Drop pte_mfn and mfn_pte Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 03/20] xen: Add Xen specific page definition Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 04/20] xen/grant: Introduce helpers to split a page into grant Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 05/20] xen/grant: Add helper gnttab_page_grant_foreign_access_ref_one Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 06/20] block/xen-blkfront: Split blkif_queue_request in 2 Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 07/20] block/xen-blkfront: Store a page rather a pfn in the grant structure Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 08/20] block/xen-blkfront: split get_grant in 2 Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 09/20] xen/biomerge: Don't allow biovec's to be merged when Linux is not using 4KB pages Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 10/20] xen/xenbus: Use Xen page definition Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 11/20] tty/hvc: xen: Use xen " Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 12/20] xen/balloon: Don't rely on the page granularity is the same for Xen and Linux Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 16:39   ` Stefano Stabellini
2015-09-07 16:39     ` Stefano Stabellini
2015-09-07 16:39   ` Stefano Stabellini
2015-09-07 15:33 ` [PATCH v4 13/20] xen/events: fifo: Make it running on 64KB granularity Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` Julien Grall [this message]
2015-09-07 15:33 ` [PATCH v4 14/20] xen/grant-table: " Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 15/20] block/xen-blkfront: Make it running on 64KB page granularity Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 16/20] block/xen-blkback: " Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 17/20] net/xen-netfront: " Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 18/20] net/xen-netback: " Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 16:57   ` Wei Liu
2015-09-07 16:57     ` Wei Liu
2015-09-08 11:07     ` Julien Grall
2015-09-08 11:07     ` [Xen-devel] " Julien Grall
2015-09-08 11:07       ` Julien Grall
2015-09-08 11:09       ` Wei Liu
2015-09-08 11:09         ` Wei Liu
2015-09-08 11:09       ` Wei Liu
2015-09-07 16:57   ` Wei Liu
2015-09-07 15:33 ` [PATCH v4 19/20] xen/privcmd: Add support for Linux " Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-07 15:33 ` [PATCH v4 20/20] arm/xen: Add support for " Julien Grall
2015-09-07 15:33 ` Julien Grall
2015-09-07 15:33   ` Julien Grall
2015-09-11 19:39 ` [PATCH v4 00/20] xen/arm64: Add support for 64KB page in Linux Julien Grall
2015-09-11 19:39 ` [Xen-devel] " Julien Grall
2015-09-11 19:39   ` Julien Grall
2015-09-14  8:56 ` Roger Pau Monné
2015-09-14  8:56   ` Roger Pau Monné
2015-09-14 10:40   ` Julien Grall
2015-09-14 10:40   ` Julien Grall
2015-09-14 10:40     ` Julien Grall
2015-09-14 11:04     ` Roger Pau Monné
2015-09-14 11:04       ` Roger Pau Monné
2015-09-14 11:21       ` Julien Grall
2015-09-14 11:21       ` Julien Grall
2015-09-14 11:21         ` Julien Grall
2015-09-14 12:08         ` Roger Pau Monné
2015-09-14 12:08         ` Roger Pau Monné
2015-09-14 12:08           ` Roger Pau Monné
2015-09-14 12:47           ` Julien Grall
2015-09-14 12:47           ` Julien Grall
2015-09-14 12:47             ` Julien Grall
2015-09-14 14:29             ` Roger Pau Monné
2015-09-14 14:29             ` Roger Pau Monné
2015-09-14 14:29               ` Roger Pau Monné
2015-09-14 14:46               ` Julien Grall
2015-09-14 14:46                 ` Julien Grall
2015-09-14 14:46               ` Julien Grall
2015-09-14 14:54               ` Stefano Stabellini
2015-09-14 14:54               ` Stefano Stabellini
2015-09-14 14:54                 ` Stefano Stabellini
2015-09-14 15:23                 ` Roger Pau Monné
2015-09-14 15:23                   ` Roger Pau Monné
2015-09-22 10:59                   ` Ian Campbell
2015-09-22 10:59                   ` Ian Campbell
2015-09-22 10:59                     ` Ian Campbell
2015-10-06  9:28                     ` Roger Pau Monné
2015-10-06  9:28                       ` Roger Pau Monné
2015-10-06 10:17                       ` Ian Campbell
2015-10-06 10:17                       ` Ian Campbell
2015-10-06 10:17                         ` Ian Campbell
2015-10-06 13:55                       ` Stefano Stabellini
2015-10-06 13:55                         ` Stefano Stabellini
2015-10-06 13:55                       ` Stefano Stabellini
2015-10-06  9:28                     ` Roger Pau Monné
2015-09-14 15:23                 ` Roger Pau Monné
2015-09-18 14:10           ` Julien Grall
2015-09-18 14:10             ` Julien Grall
2015-09-18 14:10           ` Julien Grall
2015-09-14 11:32       ` Arnd Bergmann
2015-09-14 11:32         ` Arnd Bergmann
2015-09-15 13:14         ` [Xen-devel] " David Vrabel
2015-09-15 13:14           ` David Vrabel
2015-09-15 13:24           ` Arnd Bergmann
2015-09-15 13:24           ` [Xen-devel] " Arnd Bergmann
2015-09-15 13:24             ` Arnd Bergmann
2015-09-15 13:14         ` David Vrabel
2015-09-14 11:32       ` Arnd Bergmann
2015-09-14 11:04     ` Roger Pau Monné
2015-09-14  8:56 ` Roger Pau Monné
2015-09-29 16:27 ` David Vrabel
2015-09-29 16:27 ` [Xen-devel] " David Vrabel
2015-09-29 16:27   ` David Vrabel
2015-09-29 16:33   ` Julien Grall
2015-09-29 16:33     ` Julien Grall
2015-09-29 16:36     ` David Vrabel
2015-09-29 16:36       ` David Vrabel
2015-09-29 16:36     ` David Vrabel
2015-09-29 16:33   ` Julien Grall

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