From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7D0AE27B4E4; Fri, 10 Oct 2025 23:06:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760137610; cv=none; b=DLSOQpJLaxEezMPjJCOflmd8IXkbsDxjHoVcQT9rJgJhpwhBNHp+qEUMdPuqEyQQRN+r/ibT+B46xftclnN1KIiFd7xebijXLXoorcyXHGp+p5A3+LFWMRduYxPzIiIkzLUxWPo4/mFriYA9k3jYLP10WT4KF29XZoxmtD8goTg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760137610; c=relaxed/simple; bh=vP5QNSY1W31DnU2sT3J2iOCPuLZnuDapSlYjRFxK/n4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Otknbs9r/9tkPkvpAiUJTj6w72AZIK8zAqhxGI8Ix9TGUTMSApXmfPkfzdk6mY7fQhPiWavhYOzeN/f2SLaBqD7ieBK43FypZhRrVHMK0M3Yd4COKCvFztpHBYgaVCBxnVKkNc8PBLAkrniRUop34qzVO7ta0MkwiXITiGrb+pY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=TS8lkZH6; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="TS8lkZH6" Received: from [100.65.97.55] (unknown [20.236.11.102]) by linux.microsoft.com (Postfix) with ESMTPSA id B0DC4201601D; Fri, 10 Oct 2025 16:06:44 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B0DC4201601D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1760137605; bh=mwIFeJ1KKd5Sc2uIhclnh5A/XfzapTJ/Acz9suBhQ20=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TS8lkZH6I5W3fD+l1DI5DtiA8OibFFmYmowc7nJnvK0wZm4h0JjBXxEmaMVAkfPTM cE0QFG0LV1ZKkfyBbiKCq0FeNNFei8iPvTQoHwv1+ViLxgm9/jqKrlqf8mjENGFO8J FJfTIgsZ9rCtoAr/0OCsepPWE00AxRrHhxPk3p84= Message-ID: <5be44d00-2a34-49cf-828f-105c2e07874b@linux.microsoft.com> Date: Fri, 10 Oct 2025 16:06:43 -0700 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 3/5] Drivers: hv: Batch GPA unmap operations to improve large region performance To: Stanislav Kinsburskii , kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com Cc: linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org References: <175976284493.16834.4572937416426518745.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> <175976318688.16834.16198650808431263017.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> Content-Language: en-US From: Nuno Das Neves In-Reply-To: <175976318688.16834.16198650808431263017.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/6/2025 8:06 AM, Stanislav Kinsburskii wrote: > Reduce overhead when unmapping large memory regions by batching GPA unmap > operations in 2MB-aligned chunks. > > Use a dedicated constant for batch size to improve code clarity and > maintainability. > > Signed-off-by: Stanislav Kinsburskii > --- > drivers/hv/mshv_root.h | 2 ++ > drivers/hv/mshv_root_hv_call.c | 2 +- > drivers/hv/mshv_root_main.c | 28 +++++++++++++++++++++++++--- > 3 files changed, 28 insertions(+), 4 deletions(-) > > diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h > index e3931b0f12693..97e64d5341b6e 100644 > --- a/drivers/hv/mshv_root.h > +++ b/drivers/hv/mshv_root.h > @@ -32,6 +32,8 @@ static_assert(HV_HYP_PAGE_SIZE == MSHV_HV_PAGE_SIZE); > > #define MSHV_PIN_PAGES_BATCH_SIZE (0x10000000ULL / HV_HYP_PAGE_SIZE) > > +#define MSHV_MAX_UNMAP_GPA_PAGES 512 > + > struct mshv_vp { > u32 vp_index; > struct mshv_partition *vp_partition; > diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c > index c9c274f29c3c6..0696024ccfe31 100644 > --- a/drivers/hv/mshv_root_hv_call.c > +++ b/drivers/hv/mshv_root_hv_call.c > @@ -17,7 +17,7 @@ > /* Determined empirically */ > #define HV_INIT_PARTITION_DEPOSIT_PAGES 208 > #define HV_MAP_GPA_DEPOSIT_PAGES 256 > -#define HV_UMAP_GPA_PAGES 512 > +#define HV_UMAP_GPA_PAGES MSHV_MAX_UNMAP_GPA_PAGES > > #define HV_PAGE_COUNT_2M_ALIGNED(pg_count) (!((pg_count) & (0x200 - 1))) > > diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c > index 97e322f3c6b5e..b61bef6b9c132 100644 > --- a/drivers/hv/mshv_root_main.c > +++ b/drivers/hv/mshv_root_main.c > @@ -1378,6 +1378,7 @@ mshv_map_user_memory(struct mshv_partition *partition, > static void mshv_partition_destroy_region(struct mshv_mem_region *region) > { > struct mshv_partition *partition = region->partition; > + u64 gfn, gfn_count, start_gfn, end_gfn; > u32 unmap_flags = 0; > int ret; > > @@ -1396,9 +1397,30 @@ static void mshv_partition_destroy_region(struct mshv_mem_region *region) > if (region->flags.large_pages) > unmap_flags |= HV_UNMAP_GPA_LARGE_PAGE; > > - /* ignore unmap failures and continue as process may be exiting */ > - hv_call_unmap_gpa_pages(partition->pt_id, region->start_gfn, > - region->nr_pages, unmap_flags); > + start_gfn = region->start_gfn; > + end_gfn = region->start_gfn + region->nr_pages; > + > + for (gfn = start_gfn; gfn < end_gfn; gfn += gfn_count) { > + if (gfn % MSHV_MAX_UNMAP_GPA_PAGES) > + gfn_count = ALIGN(gfn, MSHV_MAX_UNMAP_GPA_PAGES) - gfn; > + else > + gfn_count = MSHV_MAX_UNMAP_GPA_PAGES; > + > + if (gfn + gfn_count > end_gfn) > + gfn_count = end_gfn - gfn; > + > + /* Skip if all pages in this range if none is mapped */ nit: comment grammar. Suggest "Skip all pages in this range if none are mapped" Looks good otherwise. Reviewed-by: Nuno Das Neves > + if (!memchr_inv(region->pages + (gfn - start_gfn), 0, > + gfn_count * sizeof(struct page *))) > + continue; > + > + ret = hv_call_unmap_gpa_pages(partition->pt_id, gfn, > + gfn_count, unmap_flags); > + if (ret) > + pt_err(partition, > + "Failed to unmap GPA pages %#llx-%#llx: %d\n", > + gfn, gfn + gfn_count - 1, ret); > + } > > mshv_region_invalidate(region); > > >