From: Arun KS <arunks@codeaurora.org> To: Juergen Gross <jgross@suse.com> Cc: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, boris.ostrovsky@oracle.com, akpm@linux-foundation.org, dan.j.williams@intel.com, mhocko@suse.com, vbabka@suse.cz, iamjoonsoo.kim@lge.com, gregkh@linuxfoundation.org, osalvador@suse.de, malat@debian.org, kirill.shutemov@linux.intel.com, jrdr.linux@gmail.com, yasu.isimatu@gmail.com, mgorman@techsingularity.net, aaron.lu@intel.com, devel@linuxdriverproject.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, xen-devel@lists.xenproject.org, vatsa@codeaurora.org, vinmenon@codeaurora.org, getarunks@gmail.com Subject: Re: [PATCH v3] memory_hotplug: Free pages as higher order Date: Thu, 27 Sep 2018 13:41:45 +0530 [thread overview] Message-ID: <21949851c3b2c82853588101f39f1207@codeaurora.org> (raw) In-Reply-To: <36488c0e-6bae-e277-2cdb-32d0dcc40065@suse.com> On 2018-09-27 12:41, Juergen Gross wrote: > On 27/09/18 08:58, Arun KS wrote: >> When free pages are done with higher order, time spend on >> coalescing pages by buddy allocator can be reduced. With >> section size of 256MB, hot add latency of a single section >> shows improvement from 50-60 ms to less than 1 ms, hence >> improving the hot add latency by 60%. >> >> Modify external providers of online callback to align with >> the change. >> >> Signed-off-by: Arun KS <arunks@codeaurora.org> >> --- >> Changes since v2: >> reuse code from __free_pages_boot_core() >> >> Changes since v1: >> - Removed prefetch() >> >> Changes since RFC: >> - Rebase. >> - As suggested by Michal Hocko remove pages_per_block. >> - Modifed external providers of online_page_callback. >> >> v2: https://lore.kernel.org/patchwork/patch/991363/ >> v1: https://lore.kernel.org/patchwork/patch/989445/ >> RFC: https://lore.kernel.org/patchwork/patch/984754/ >> >> --- >> drivers/hv/hv_balloon.c | 6 ++++-- >> drivers/xen/balloon.c | 18 ++++++++++++++--- >> include/linux/memory_hotplug.h | 2 +- >> mm/internal.h | 1 + >> mm/memory_hotplug.c | 44 >> ++++++++++++++++++++++++++++++------------ >> mm/page_alloc.c | 2 +- >> 6 files changed, 54 insertions(+), 19 deletions(-) >> > > ... > >> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c >> index e12bb25..010cf4d 100644 >> --- a/drivers/xen/balloon.c >> +++ b/drivers/xen/balloon.c >> @@ -390,8 +390,8 @@ static enum bp_state >> reserve_additional_memory(void) >> >> /* >> * add_memory_resource() will call online_pages() which in its turn >> - * will call xen_online_page() callback causing deadlock if we don't >> - * release balloon_mutex here. Unlocking here is safe because the >> + * will call xen_bring_pgs_online() callback causing deadlock if we >> + * don't release balloon_mutex here. Unlocking here is safe because >> the >> * callers drop the mutex before trying again. >> */ >> mutex_unlock(&balloon_mutex); >> @@ -422,6 +422,18 @@ static void xen_online_page(struct page *page) >> mutex_unlock(&balloon_mutex); >> } >> >> +static int xen_bring_pgs_online(struct page *pg, unsigned int order) >> +{ >> + unsigned long i, size = (1 << order); >> + unsigned long start_pfn = page_to_pfn(pg); >> + >> + pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, >> start_pfn); >> + for (i = 0; i < size; i++) >> + xen_online_page(pfn_to_page(start_pfn + i)); > Hi, > xen_online_page() isn't very complex and this is the only user. > > Why don't you move its body in here and drop the extra function? > And now you can execute the loop with balloon_mutex held instead of > taking and releasing it in each iteration of the loop. Point taken. Will incorporate them. Regards, Arun > > > Juergen
prev parent reply other threads:[~2018-09-27 8:11 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-27 6:58 Arun KS 2018-09-27 7:09 ` Oscar Salvador 2018-09-27 8:09 ` Arun KS 2018-09-27 7:11 ` Juergen Gross 2018-09-27 8:11 ` Arun KS [this message]
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