Date: Sun, 03 Dec 2017 04:59:39 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 223831] [patch] swap_pager.c to release multiple swap blocks at a time Message-ID: <bug-223831-8-57Xe2RVYqa@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-223831-8@https.bugs.freebsd.org/bugzilla/> References: <bug-223831-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D223831 --- Comment #3 from ota@j.email.ne.jp --- (In reply to Konstantin Belousov from comment #2) Indeed, 1st patch chunk failed and I overlooked it. Also, I missed offset initialization. To answer your question, I started with 2 reasons. #1 - I started looking at optimizing page-in cases and process exit cases w= here they had released 1 block at a time although swp_pager_freeswapspace() takes npages to free. This was the 3rd one. #2 - swp_pager_force_pagein() comment says "it doesn't work" and I wondered why. The reason I found is we need to call vm_page_grab for the number of pages we want to page in. Summing up, after I figured vm_page part, the code started working okay and based on my observation of "top", multi-block page-in was considerably fast= er - reading 1 block 32 times compare to 32 blocks a time. It looksvm_object_t = is locked during swapoff operation (while paging-in), too. During research, I found swap_pager_getpages() calls swap_pager_haspage() anyway and swap_pager_haspage() checks how many continuous blocks are behin= d.=20 So, I started researching from swap_pager_haspage() side instead of swblk s= ide. I had few questions like when to lock and how and when to increment vm_object_pip. I posted here for some feed backs. While checking patch failure against HEAD, I realized swp_pager_force_pagei= n() in HEAD had a change for (m->valid =3D=3D VM_PAGE_BITS_ALL) case. This cha= nge cleared some of my questions. I will update my changes and post a new one = for 11-STABLE and HEAD. --=20 You are receiving this mail because: You are the assignee for the bug.=
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